FAQs about Suspensions


  • Progressive springs.
  • Spring rates for different series.
  • Spring rate equation.
  • How do I replace the strut tower lower spring?
  • Should I replace only the rear anti-sway bars?
  • Approach to suspension performance modifications.
  • Can I use a generic balljoint tool?
  • I bought a rear bushing kit and I have bushings left over, what happened?
  • Are there any trick to installing rear springs?
  • Questions about 242GT springs.
  • What do the ball joints do and what are the symptoms when they wear out?


  • Progressive Springs.

    From: John_E_Werner.Wbst311@xerox.com
    Subject: Re: progressive springs
    To: volvo-net@me.rochester.edu

    >So Roman is right on the money with his wire diameter measurements to
    >determine the k for different springs. (N, D, and G don't change in volvo
    >springs, only small d, the diameter.)

    Actually, that should read: "(N, D, and G don't change in_most_stock_ volvo springs, only the diameter.)" Volvo used to make, and still has some supply of, progressive springs. They were available for everything from the 120 to the 200 series cars. The 120 series are no longer available (I am looking for a set for my 122 if anyone has any leads). The 140 series springs, both front and rear, are still stocked. I have not checked on the 200 series ones. The cost of the springs is a bit more then any other brands I have seen.

    The springs actually change wire diameter and the number of coils per unit length (i.e. the coils get close together), making d and N both functions of x, the displacement. The result is a reasonably soft spring at stock height, and an almost rock hard spring near full compression.

    The biggest problem is ording them. They are no longer listed in teh parts catalogs. They are in the Volvo R-Sport catalogs and on the shelves in the Volvo wharehouse. It helps to be on good terms with a volvo parts guy. To give you an idea of how fast the set are being bought, I order a set of rear springs for a 140 from my local dealer, Best Motors. They arrived on a standard stock order in about a week. The next time the Volvo Sales Reps were through here, Rochester, NY, they reportedly asked them who this John Werner person who is ording all of these old parts was.

    -- John

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    Spring rates for different series.

    Date: Tue, 8 Oct 91 09:01:58 EDT
    From: Roman Ford <ford@me.rochester.edu>
    To: jxs18@po.cwru.edu
    Subject: Re: spring rates

    Morning Jerry,

    I've been doing some research on spring rates for the different models, so I'll share some of the info cause you didn't mention whether you bought your strut asmby at a junkyard, or new. 240's generally run a lower spring rate than 260's and this can be measured with a micrometer. Measure the thickness of the spring, and then count the number of turns total in the spring, being careful to count all of them - when they are installed in the strut it is sometimes difficult to feel the pigtails. This however, is not so important as the thickness, because I found that all the stock springs I looked at were all the same length.

    240 sedan, wagon, and turbo (US model) 13.5mm to 13.8mm

    All 240 except the 1979 GT are sprung quite softly, and later ones have even softer springing (thinner spring)

    260 V6, diesel 14.1mm

    260's have a substantially higher spring rate in front.

    As you can see, if you got a spring from a 240, it's not going to work properly. BTW spring rate is directly related the thickness and coil diameter, but because of the strut the coil diameter is constant, the only variable is the thiichness. Oops, number of active coils is also in the equation, but this too I found to be constant on stock springs.

    I have a neat nomogram for spring calculations for anyone that wants it to help with choosing new springs.

    So, Jerry, the pulling problem sounds kinda like a balance problem in the rack, although you didn't mention anything about messing with it. There is a cap on the rack, not the flat one but the one under it, that has a bearing inside. You make up a tool to move the bearing (this is in the Haynes manual and it really works) until it takes the same force to move the steering wheel all the way to one lock as it does all the way to the other lock.

    P.S. when measuring springs, don't measure undercoating on them (does this seem obvious? Don't mean to insult your intelligence)

    roman

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    Spring rate equation.

    From: Tim Takahashi <tim@me.rochester.edu>
    To: wiegman@orion (Herman L. N. Wiegman)
    Subject: spring rate equation

    OK. From shigley...

    k = d^4 G / (8 D^3 N)
    

    d^4 G

    k= -------

    (8 D^3 N)

    where d = diameter of the wire

    G = Bulk Modulus (material property)

    D = Diameter of the spring

    N = Number of turns

    So.... yes... cutting the springs makes them "stiffer." But not by much.

    tim


    Date: Thu, 30 Nov 1995 22:14:22 -0800 (PST)
    From: tim@sr71.arc.nasa.gov ((28.8)Timothy Takahashi)
    To: swedishbricks , Scott Allard
    Subject: Re: F 240 Susp. springs again

    Somebody was asking about front spring stiffnesses, I'll repost (an edited) copy of some calculations made by Scott Allard.

    -tim

    >From: Scott Allard (scotta@dgs.dgsys.com)
    >To: swedishbricks (swedishbricks@me.rochester.edu)
    >Subject: F 240 Susp. springs again

    >OK. So I took Tim's data on spring diameters and all, combined with the
    >spring rate formula (thanks to the Klaver Klan), checked Haynes for more
    >data, and this is what I got.

    > Rate, lb-in. Rate, n-m
    >FRONT 242/244/245 117 13
    >FRONT 242GT 148 17
    >REAR 242/244 114 13
    >REAR 245 120 14

    In terms of spring rate per "axle" the spring rates add (springs in parallel). So the effective front spring rate on a 200 series is typically 230 lbf/in and the rear spring rate 230-240 lbf/in.

    N.B. : The R-Sport catalog claims the GT springs are 35% stiffer, though by Scotts calculations they are only 27% stiffer.

    Either way, the combination of stiffer front springs and large R-Sport rear sway bar works nicely.

    -tim

    ---------------------------------------------------------------------------
    Timothy Takahashi EMAIL : tim@sr71.arc.nasa.gov
    M/S 247-2 (AA/AAL) PHONE : 415-604-4976
    NASA Ames Research Center U. Rochester Alum
    Moffett Field, Ca. 94035 & Swedishbrick Enthusiast

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    How do I replace the strut tower lower spring?

    Date: Wed, 2 Sep 92 07:17:18 -0400
    From: emf@coos.dartmouth.edu (Eric Friets)
    To: swedishbricks@me.rochester.edu
    Subject: strut seats repaired

    I replaced the strut tower lower spring seat yesterday. Here's the procedure:

    jack up car, remove wheel
    remove tie-rod end, sway bar connection, brake line bracket
    loosen strut top nut, inside engine bay
    remove 3 nuts holding strut/spring assembly to tower
    lower unit out (it hinges on the A arm)
    compress spring, remove upper spring seat
    remove strut (I replaced them while I was there...)
    cut old spring seat off 10mm above the weld
    (it is welded to the tube that goes down
    to the axle/brake/ball joint setup)
    clean up, paint, rustproof
    slide new seat on; it aligns by a small tab in the
    old drain hole
    reassemble

    It took about 3 hours for one side, which was broken. The other side is not broken, but I will do it anyway, since its rusted, winter is coming, and I put a new strut cartridge on one side.

    The worst part is cutting the old seat off. I used a powered hacksaw (really a small bandsaw), made by Milwaukee, which is bulky and heavy, but cuts a lot faster than I do by hand...

    The parts (two seats, left and right) were $46 at list price from the local Volvo dealer. They come with good instructions.

    Thanks to those who sent advice. Volvo's solution to this common problem is good. The rust that caused the problem is almost completely cut off with the old seat, so I think this is better than installing a used strut assembly. The labor is probably about the same, maybe less, and the result is probably a little better. And I doubt you could get *two* used struts for $46...

    Eric Friets

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    Should I replace only the rear anti-sway bars?

    Date: Thu, 30 Jan 1992 10:33:10 PST
    From: Frank_Bov.Wbst311@xerox.com
    Subject: Re: Replacing only the Rear Anti-Sway Bars on 745
    To: volvo-net@me.rochester.edu

    Bill and all,

    There may be a very good reason why IPD strongly recommends against installing a rear anti-sway bar without upgrading the front bar. The car will tend to be more tail happy, with a (possibly strong) tendency to spin at the limit.

    For a bunch or reasons I won't go into, most cars, including Volvos, are designed to understeer at the limit. As drivers, we are accustomed to that sort of handling. If you start changing the front / rear balance, the handling characteristics can change dramatically.

    All cars understeer at the start of a turn. While you can make a car so tail happy it understeers everywhere, the problems usually occur at the transition from understeer to oversteer. If you're not trained to handle it, or it occurs suddenly, you can end up off the road facing backwards. Don't ask how many times I've spun looking for the limit on the track or at an autocross. They key is balance, where all four tires contribute equally to getting you around corners. Stiffening one end or the other alone usually hurts handling in my experience.

    And, of course, there is the basic question: Why didn't Volvo put one there in the first place? I seem to recall that our '85 245 has a rear bar; I know our '81 244 does. Maybe the 745's are harder to control when loaded, or at high speed (higher speed also shifts the handling balance toward oversteer). Consider the penny wise / pound foolish school of thought: buying the set won't cost that much more compared with the cost of the car and the potential dangers of capricious handling. Plus, I'll bet the pair are cheaper when purchased together, instead of singly.

    Well, that's my 2 cents worth. Hope this make sense. I _have_ been know to ramble . . .

    Frank

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    Approach to suspension performance modifications.

    Date: Wed, 14 Apr 93 09:50:22 EDT
    From: wiegman@orion (Herman L. N. Wiegman)
    To: mhs2z@adminsun.ee.virginia.edu
    Subject: suspension tuning

    Max, [and fellow suspension freek netters]

    You now know what the enthusiast feels after installing the sway bars.. "hmm.. Not bad, but not a great difference.. " Most normal Volvo owners are impressed with the more controlled feel. (makes you wonder why VCNA doesn't up their sway bar rates... they have upgraded the sway bars over the 1975~1982 period but not after that??)

    I think that the 745 will never handle as nicely as the Prelude. Simply, the 745 tips the scales 800 pounds more than the Honda.

    Assuming that you have decent 60 series or 55 series HR or VR tires, the next step for you will be to upgrade the shocks to Bilsteins. That makes the cornering a bit more crisp. (Koni's and Tokiko's are also acceptable, but are not of the same quality..i.e. they don't last 100kmiles like the Bilsteins.)

    After swaybars and shocks have been added and you are still interested in more "corner throwing" performance, I would recommend the lowering coils. These come with a price in ride smoothness and winter driving performance.

    APPROACH TO SUSPENSION PERFORMANCE MODIFICATIONS

    [herm's point of view.. what do the other "corner throwing" netters' think?]

     0) OBTAIN MORE AGGRESIVE ALIGNMENT AND INSPECT ALL BUSHINGS:
    

    Most older 'bricks' can be freshened with a good set of bushings and more negative camber and a slight toe-in setting.

    1) UPGRADE THE QUALITY OF THE TIRES:

    Includes snow and summer sets for the Northern netters. HR rated tires are the most 'bang for the buck.' See Tire Summary.

    2) UPGRADE THE QUALITY OF THE SHOCKS:

    Turbo Gas, Bilstein's, Koni's or simply better quality than what the brick has presently. ( could have non OEM brand )

    3) ADD STIFFER ANTI-SWAY BARS:

    This step adds performance equipment to your car.. the last three steps are less invasive and replace components which normally wear. Front sway bars should be stiffer than the rear bars... A smaller front sway bar is dangerous/unstable.

    4) CONSIDER LOWERING COILS:

    This step is for the crazy folks who like to Autocross or play boy/girl-racer on their way to work. Not recommended for pot-hole ladened streets or for winter driving.

    5) MODIFY THE FRONT CONTROL ARMS/SUSPENSION GEOMETRY:

    The front control arms usually limit the practical camber/caster which is available to the suspension tuner. In order to overcome the natural King Pin angle, an aggresive Caster (4~6*) must be implemented. The top of the strut tower can be modified to accept a camber/caster adjustment plate (for Datsun 240Z's). This is the ultimate setup for autocross or track.

    6) MODIFY THE REAR CONTROL ARMS/SUSPENSION GEOMETRY:

    I have seen a DeDion type Panhard rod in the rear of a 240T. Pretty slick... how 'bout a "Z" bar???

    herm

    p.s. back to the lab for me.. awaiting the 5:00PM e-mail responses...

    Herman L.N. Wiegman -> wiegman@orion.crd.ge.com
    General Electric - Corporate R&D, Schenectady NY
    - the Flying Dutchman in the DSP Swedish Brick -


    Date: Wed, 18 Aug 93 11:33:44 PDT
    From: megatest!bldg2fs1!sfisher@uu2.psi.com (Scott Fisher)
    To: anabhan@midway.uchicago.edu
    Subject: Suspension Tuning 101

    > P.S. Last night I drove a really nice 764T with the IRS. It put power down
    > out of corners much better than the 740's live axle, but it was too soft.
    > Lotsa understeer and it dove like frisky porpoise under braking.Would the
    > IPD bars help?

    They ought to help with the understeer, but not with the dive. That's a function of suspension geometry and spring rates at either or both ends of the car.

    If you want to fix understeer, here's a list in increasing order of cost:

    1. Pump the front tires higher. Cost: Free. This will reduce the amount that the tire rolls over under cornering loads. If you drove this car on a dealer's lot, it's probably 20 to 25 pounds too low all around - they go for that boulevard ride every time. Start with the maximum printed on the sidewall and move up in 2-lb increments from there till you can't observe a change in the car's behavior (or you dislike the way the car behaves), and then back off two pounds.

    Tradeoffs: On the plus side, this will sharpen steering response even at small movements of the wheel (say, tracking a lane on the freeway). It might also help fuel economy, but not as much as pumping all four tires up to the higher pressure will. On the minus side, it will make your car ride a little more roughly, and can increase noise and feedback from the steering wheel. In a small open sports car, these are all either features or no-ops (you can't hear road noise when the wind is whipping past your ears at 65 mph); in a luxo-Brick full of crabby in-laws, well, you be the judge. :-)

    2. Add negative camber. Cost: Depends. If you've got good tools, you can do this yourself for only labor and (maybe) some shims. Negative camber is when the tops of the tires are closer than the bottoms (so that they look knock-kneed from the front). Not all cars are tunable for more negative camber, and not all manuals tell you how to do it, but keep reading. In a pinch, you can usually have a good shop do it for you for under $50 per "axle".

    How much to add depends on your abilities, budget, and intended use. If you are approaching this systematically with sweat equity and little capital, try 1/4-degree increments till you like the way the car drives. If you're approaching this with a big budget and no patience, dial in all the negative camber the car will stand and then see how many weeks it takes to wear the insides of your tires down to the cords. You will feel a remarkable difference with as little as 1.2 degrees of negative camber.

    Trade-offs: What this does is change the static angle of the front tires so that when the chassis leans in a corner, the tires are closer to vertical. On the plus side, this keeps them more flat on the ground and the superior traction this affords (compared to being slightly tilted) makes them stick better. On the minus side, if you spend most of your time just motoring around town, you will wear out the inside edges of your front tires because they're tilted when the car goes straight ahead. And the cost is about $50 for most good shops, but of course this jumps dramatically if you end up wearing out a set of tires in 6000 miles instead of 30,000.

    3. Add anti-roll bars. This will have a far greater impact on the way you perceive your car's handling at anything greater than parallel-parking speeds than anything else I've discussed so far. We've been through them several times on the list, so the quick recap is that an anti-roll bar lifts up the inside tire, which makes the car want to fall back down onto it. This keeps the car flatter in a corner, but it reduces the overall downforce on that end of the car (because it's lifting the tire, and thanks to Phil Ethier of the britcars list for that analogy). There's also some weird stuff that happens on some cars when you mix anti-roll bars with (um) overly conservative front suspension geometry, but as a general rule, add a stiffer bar to the end *opposite* from the one you're having trouble with. If the car plows, stiffen the rear; if the tail wants to come out, stiffen the front.

    Trade-offs: This has no effect on linear bumps -- meaning that on the one hand, the car won't handle any stiffer when you hit an expansion strip, but on the other, it won't resist dive and squat (the way the nose comes up like a powerboat when you tromp on the gas). It also is the most expensive item so far, running up to a couple hundred dollars for sway bars at both ends of new cars. Note also that you will almost certainly want to add a bar to both ends, and that if so you will either want to trust your bar supplier or do a lot of reading and calculation of load rates.

    3a. You can also tune anti-roll bars by bushing material. Most stock anti-roll bars use soft rubber bushings that offer a lot of compliance to light loads. Bushings of polyurethane, Carsan, or nylatron (different varieties of synthetics with differing degrees of stiffness) will reduce anti-roll bar preload. Solid metal bushings will eliminate preload, but will be VERY noisy and will ultimately grind your anti-roll bar into powder unless lubricated every time you drive the car. This is not much incremental effort for a race team, which might well lap the valves every race, but it's probably more than anyone but John Werner wants to do on this list. Trade-offs: Cheap, but a fair amount of labor; can be used to fine-tune existing bars. You can also tune the end link bushings so that the bar doesn't hook up for the first few fractions of an inch of roll, for instance, which can change the response curve of the anti-roll bar. There's a lot you CAN do: the hard part is deciding what you SHOULD do. :-)

    That's all for now. Hope this is beneficial to some of you!

    --Scott


    Date: Wed, 18 Aug 1993 12:38:28 PDT
    From: werner.wbst311@xerox.com
    Subject: Re: Suspension Tuning 101
    To: megatest!bldg2fs1!sfisher@uu2.psi.com

    >2. Add negative camber....
    >What this does is change the static angle of the front tires
    >so that when the chassis leans in a corner, the tires are closer to
    >vertical.

    The effects of negative camber are really only helpful in highspeed, low steering angle corners. If the wheel are turned sharply, the camber has little to do with the angle of the tire to the ground. CASTER now comes into effect, and adding positive caster can help slow speed, high steering angle corners at the cost of heavyness of steering.

    BTW: Many new cars have no adjustments for Caster and Camber. The struts only fit one way and you can not adjust them. It makes life for many of us 'hot rodders' a little more of a pain. It also can get into some big problems when the frame gets bent.

    >3. Add anti-roll bars.

    Consider the trade offs very carefully when you make the wheels non-independent from side to side. For race tracks, a big, solid bar is great, but it hinders when the going is rough. Most people setting up for off-road (backwoods rallying) actually go to smaller sway bars. This allows the tires to stay on the ground over the really rough stuff. A big sway bar is no help when your tires are off the ground. (The same goes for steering when the car is off the ground, but that is a rally story for another time....)

    4. Springs

    Stiffer springs will help the car from leaning nearly as much in the corners. The drawbacks are that ride quality goes down as you start to feel every pebble in the road. You may also loose some ground clearance if the springs are also designed to lower the car. (Can you afford that extra 1"?) On the other end of the spectrum, there are also springs which will raise the car. (Get a hold of the Heavy Duty, Volvo R-Sport front springs for a 140...). Both lowering and raising will due interesting things to the suspension geometry and may introduce their own problems.

    The best solution in the springs department for street use are Progressive springs. Typically, at stock weight, the car is a normal ride high and will have a slightly softer feel. When you load it up, the springs get stiffer and the car will sink less then before. This even helps in corners where body roll is trying to make one side of the car sink.

    --John


    Date: Wed, 18 Aug 93 13:27:26 PDT
    From: megatest!bldg2fs1!sfisher@uu2.psi.com (Scott Fisher)
    To: anabhan@midway.uchicago.edu
    Subject: Re: Suspension Tuning 101

    Whoops. In my suspension article, I said:

    3a. You can also tune anti-roll bars by bushing material. Most stock anti-roll bars use soft rubber bushings that offer a lot of compliance to light loads. Bushings of polyurethane, Carsan, or nylatron (different varieties of synthetics with differing degrees of stiffness) will reduce anti-roll bar preload. Solid metal bushings will eliminate preload, but will be VERY noisy and will ultimately grind your anti-roll bar into powder unless lubricated every time you drive the car.

    "Preload" in both cases should be "twisting." What happens is that if the bushings are soft, they will compress as the car rolls and makes the anti-roll bar twist in their mounts. This means that the only thing resisting the car's lean is the rubber in the bushings. By going to a firmer material, you eliminate the time it takes for the bars to start resisting lean.

    "Preload," for the edification of anyone who's still with me on this, is when you dial in -- intentionally or otherwise - an amount of twist to the anti-roll bar when the car is flat. For example, if you put a longer end link at one side of the car than at the other, you will make the car slightly out of balance by preloading the anti-roll bar in this way. This is a trick used by racing car tuners to fine-tune the amount of weight on each corner of the car; the easiest way to understand how it works is to consider a car racing on a circle track, where it only turns left, and you therefore want to put as much weight as possible on the left side of the car to keep it from leaning over onto the right wheels, but it's applicable on road-racing cars as well, to compensate for such imbalances as having the driver on one side of the centerline.

    And that's a bigger imbalance for some of us than for others... :-)

    --Scott "I said imbalance, not UNbalanced" Fisher


    Date: Thu, 19 Aug 93 12:29:41 PDT
    From: megatest!bldg2fs1!sfisher@uu2.psi.com (Scott Fisher)
    To: damouth@wrc.xerox.com
    Subject: Re: Suspension Tuning 101, Lesson 2

    >    > This keeps the car flatter in a corner, but
    >    > it **reduces the overall downforce on that end of the car** (because it's
    

    CLUE COMING: --------------------------> ^^^^^^^^^^^^^^^^^^^^^^

    > > lifting the tire, > ARRRRGGGh!!!! > I hope you were kidding! If not, I know someone who wants to talk to > you about your neat antigravity invention - you'll be rich overnight.

    If we all drove one-ended cars, you'd have a point. But even motorcycles have a front and a back (if the side-to-side part is done by the rider). (Do you live in the Bay Area? I'll take you out for a ride and show you what I mean. Wish I still had the Lotus Cortina, that was the best car for demos like this because the inside front tire would squeal on corner entry, then get quiet when I got on the gas. A little reflection made it apparent that this was because I was lifting that tire off the ground under power...)

    The weight doesn't disappear, it just moves around a lot. It not only moves from side to side, but it moves from front to back and back to front, depending on whether you're braking or accelerating. One of the best descriptions I've read recently likened weight transfer in a moving car to water in a roasting pan, sloshing not only from side to side but front to back.

    Why the anti-sway bar figures into this is that it changes the velocity at which this stuff happens and the rate at which this stuff happens, and these two changes are relatively independent. If you corner hard enough to lift the tire (see above), not all the weight from that lifted tire goes to the outside of that same end of the car (see above). Some of it -- even if you assume a steady-state condition, and I am almost prepared to argue that such conditions do not exist except in the imagination of first-year physics students, and certainly never on a race-track -- is going to be transferred to the other end of the car simply by virtue of the fact that the chassis is fairly stiff (particularly on our bricks).

    And by the way, by "lift the tire" I don't exclusively mean picking the tire up in the air like the inside rear of a GTI, though of course that is the extreme example (except maybe for John's example of making the whole car fly, something most of us pavement racers generally try to avoid :-). I'm talking about the shift of weight off, say, the inside front tire as the car starts accelerating out of a corner with the wheels still turned, or the shift off the inside rear corner as you brake (or just get off the gas) with the wheels turned. Or even the shift off both insides if you have unbalanced anti-roll bars, which is what this whole lurid diatribe started off to explain was such a bad idea unless you know what you're doing.

    The net result is that the weight is transferred *across* the car by the anti-sway bar, but *forward or backward* in real life by the car's chassis, under the influence of velocity, acceleration or deceleration, and the car's natural weight distribution. Nose-heavy cars tend to unweight the rear end even in the semi-mythical steady-state corner, simply because there's more weight up front; tail-heavy cars, such as the 911, tend to unweight the front more in a relatively steady corner because there's more weight in the rear, but the 911 is a pathological example worthy of lots more study; I'll be happy to demonstrate to anyone who wants me to take your 911 around a track at speed for you :-).

    The result of this biaxial transfer is that you typically - now read carefully --

    reduce the overall downforce on one end of the car because when it reduces the weight on the inside tire, it transfers the weight not only across the car but also to the other end of the car.

    That's the missing link. Each end of the car is attached, pretty firmly on modern cars, to the opposite end.

    (This stuff gave me *fits* when I was first trying to understand it. It gives everyone fits. Wait till I start talking about the friction circle... :-)

    > Meanwhile, I'd like to sell you this need set of boot straps that you
    > can lift yourself up with ....

    Naw, I have those on my computer!

    --Scott "Didn't even mention weight change when the passenger upchucks" Fisher


    Date: Sun, 22 Aug 93 21:41:42 EDT
    From: Tim Takahashi <tim@me.rochester.edu>
    To: megatest!bldg2fs1!sfisher@uu2.psi.com (Scott Fisher),
    Subject: Re: More About Suspensions

    On Aug 22, 3:58pm, Scott Fisher wrote:

    } Subject: More About Suspensions
    } > Oh oh! I can hear Tim grumbling in the background already.
    } Um, I'm *not* screwed up on this.
    }
    } 1. The fact that there are springs at both ends of the cars means that
    } a transfer of weight at one end implies (through the car's frame)
    } a transfer of weight at the other. In practice, this means that
    } adding an anti-roll bar to only one end of the car will *still*
    } affect the opposite end's grip, because the curve of roll angle to
    } vehicle speed will be different due to the change in front-rear
    } weight transfer during cornering.

    } 2. Stiffer springs (or anti-roll bars) will change....everything about
    } the way it handles.

    "Doc" Tim will now grumble....

    Scott is correct. In fact the suspension geometry (which controls the effective "roll centers" of the chassis) is very different between 140/160 series cars and 240/260 series cars. The 7xx/9xx cars are equally different depending on the rear suspension configuration "Larsson" axle vs. IRS.

    Now, from experience, I can tell you a bit about the 200 series. I've driven many of them, and have found the subjective handling to be all over the place - some are crisp, others mushy, some understeerers some oversteerers. The differences boil down to a few basic things :

    1. Tires (and wheels)
    2. Dampers (Shocks)
    3. Anti-roll bars
    4. Springs
    5. Alignment

    >From experience, you can run 1/16" toe-out on a 200 series without effecting straight line stability. In fact, I'd really reccomend it.

    Tires, well enough has been said, but I can compare two cars :

    1979 4-door sedan, stock springs, 15x7" rims, Bilsteins, IPD bars,

    205/60HR15 Continentals

    1985 Turbo wagon, IPD lowering springs, turbo alloys, Bilsteins, IPD bars,

    205/60HR15 BFGoodrich Comp T/A HR4

    The turbo wagon should have sharper turn-in and reflexes, but the sedan has more grip and sharper turn-in.

    Suspension :

    1987 4-door sedan, stock springs, stock rims, stock shocks, stock bars

    205/70HR14 Continentals

    1978 245DL wagon, stock springs, stock rims, Bilsteins, stock bars

    205/70HR14 Continentals

    The sedan understeers, the wagon oversteers. Shocks or align?????

    Align :

    My 1979 v6 sedan. before align : 5/16" toe-out

    after align : 1/16" toe-in

    Before has sharper turn in, after has softer turn-in.

    Of course, most cases are comparing apples and oranges, for as Scott has pointed out. EVERYTHING makes a difference. In the case of the 87 sedan, which my father drives, it baffles me why it understeers so much (yet with him at the wheel, wears tires evenly). I'll have to drag it up to Rochester and have the alignment checked out my my mechanic.

    Grumbling over.....

    "Doc"

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    Can I use a generic balljoint tool?

    From: alfred@nyquist.bellcore.com (Alfred Kwan 21342)
    Subject: Re: Balljoint tool = picklefork?
    To: maj@frame.com (Michael Jue)
    Date: Thu, 22 Apr 1993 10:48:15 -0400 (EDT)

    Micheal:

    > It's been a long time since I had to disassemble the front end of
    > a car and am wondering about some things...
    > On most of my other cars, when I played with the suspension system,
    > I always used a ball joint separator (aka picklefork) to
    "break"
    > the joint apart. What I need to know is, can a generic picklefork be
    > used on the front susp. of my 740T? (Looks like it but want to make
    > sure I have the right tool on hand and don't need a "special version".)

    For all the 240s and my 528i, I had very good luck with 2 J.C. Whitney tools - "deluxe heavy-duty lever type ball joint & tie rod end remover 81-2149, around $15 and "screw type ball joint remover 88-1770B around $10. I highly recommend the first one. I replaced the tie rods and the center track rod on my 528i with this tool. The old fashion ball joint fork just can't remove the center track rod. It's great for 240s on front struts replacement. The ball joint fork usually cracks the grease boots. And I don't have to beat the tie rods out with a hammer. That usually kills the top threads. Well, you get the idea, I like this tool.

    > (BTW, when I did the shocks and bars on this car, I did it using
    > the ol' "force down the control arm/strut ass'y so that it hangs
    > out of the wheel well method"...no separation of the ball joint.)
    > Secondly, when re-installing, has anyone come up with any better/
    > easier ways of pressing the ball joint back together other than
    > raising the floor jack underneath the joint?

    I usually use a big channel-lock to squeeze them back together. Not so hard, just let friction do the job. I usually can find enough room on the side for the channel-lock and still have room for the hex nut.

    Good Luck

    Alfred

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    I bought a rear bushing kit and I have bushings left over, what happened?

    Date: Fri, 7 May 93 09:36:19 EDT
    From: wiegman@orion (Herman L. N. Wiegman)
    To: LAPEDIS_RON@tandem.com
    Subject: Re: rear-end bushings

    RonL, [ and other netters with aging 240's, I hope this is helpful. ]

    > Anyway, the problem duJour is that I bought their rear-bushing
    > kit and had my Volvo dealer install them. When they were done, 8
    > bushings were left over including 4 torgue rod bushings...

    Many Volvo shops do not replace the PANHARD ROD BUSHINGS (2). This is a rod which locates the rear axle on the horizontal axis. These bushings normally don't decay.. not unless you play boy racer or tow large, 4-legged animals in a trailer over farm roads (sorry Eben [& Rupert], I had to put that in).

    Two other bushings which are seldom changed are the LEADING, REAR TRAILING ARM BUSHINGS. These are the bushings under the rear seats. They locate the arching points of the traling arms. They are a pain to replace and usually do not fail in the same way that the MAIN TRAILING ARM BUSHINGS do.

    The TORQUE ROD BUSHINGS are probably the second most problematic, especially on Turbo cars. There are three different lengths of torque rods and Tim T. can fill you in on improvements to acceleration and "axle hop."

    I like the ipd torque rod bushings. They are polyeurethane and come in two peices (two halves per bushing). This makes them a breeze to install.

    Here is some great ASCII art to locate the bushings...

             TOP View of rear suspension arms and bushings:
    

    Passngr. Trailing Arm O-------[_] []

    Passngr. Torque Rod O------| /

    ,|.|

    Differential--> | || Panhard Rod (axle to frame)

    `|'|

    Drvr. Torque Rod O------| / Rear of car ->

    Drvr. Trailing Arm O-------[ ]

    Note: rear Torque Rod bushing is not visable from below, it is on "top" of the axle.

    > After 3 months the 2 trailing arms bushings shredded and it's
    > another 3 hours labor to replace them; this time with Volvo
    > parts. The mechanic says they ripped apart due to a curved metal
    > piece molded into the rubber. This piece apparently stressed and
    > took out the rest of the bushing.

    The Main Trailing Arm Bushing does have two paranthesis like metal peices in the rubber center. The area between the "(" ")" metal tabs (on top and bottom) are void of rubber.. this makes for more road isolation. The bushing must be ORIENTED CORRECTLY OR THE BUSHING WILL FAIL. I beleive that the bushings that IPD sent you last time were good quality bushings (I have two on my 245). I also think that they were installed incorrectly.

    > should IPD pay for the replacement parts and
    > labor since it was only 90 days?

    I would recommend the new Solid bushings, but I would also recommend that you talk with the dealer service manager. It sounds like his monkeys did your bushings in. See if you can get the labor out of them (unlikely because the parts were not OEM.. OR maybe they were Volvo parts! ask ipd.)

    best of luck,

    herm

    Herman L.N. Wiegman -> wiegman@orion.crd.ge.com
    General Electric - Corporate R&D, Schenectady NY
    - the Flying Dutchman in the DSP Swedish Brick -

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    Are there any trick to installing rear springs?

    Date: Wed, 6 Oct 93 13:31:17 EDT
    From: nick@meaddata.com (Nick Gough)
    To: swedishbricks@me.rochester.edu, bausman@mcc.com, maj@frame.com
    Subject: Re: Installing Rear Springs

    > From maj@frame.com Wed Oct 6 13:21:10 1993
    > > From bausman@mcc.com Tue Oct 5 17:19:52 1993
    > > Are there any "tricks" to this installation? The IPD guys
    > > say it is very staightforward, simply pulling the lower
    > > shock bolts to release all tension on the old springs,
    > > remove them, and install the new ones.
    > Marv,

    > Uh, maybe I'm missing something here or the 2xx series is very
    > different from the 700 series? But wouldn't it be safer to use
    > a spring compressor rather than letting the sucker pop out from
    > it's own tension? Pow!!

    True, to a degree.

    I didn't use a spring compressor when I put 740 springs on my 760 rear end & pitched the worn out Nivomats. After lowering the axle (car was on stands), with the shocks out, the springs were a piece of cake to get out & install. Just had to be carefull when seating them to the towers, so they would stay in place, whilst putting load back on them, prior to putting on the new shocks.

    I'd never handle McPhearson struts in this manner, though, as the springs are under a lot of load & can fly off do a lot of damage to you or your surroundings.

    Use a spring compressor, if you have any concerns, no matter how slight, just to be safe.

    Nick

    > I know it's pretty straight forward on my 700...
    > Take off tension from the spring with a compressor, unbolt lower
    > spring perch/shock mounts and drop 'em out. (Use a floor jack to
    > lever the suspension back upon install.)
    > -maj


    Date: Wed, 13 Oct 1993 1:30:29 -0400 (EDT)
    From: STEVE (516) 282-3018 <GINELL@bnlsbc.nsls.bnl.gov>
    To: SWEDISHBRICKS@me.rochester.edu
    Subject: REAR SPRING REPLACEMENT ON 200 SERIES

    There has been some discussion on the net regarding how to replace the REAR springs on the 200 series and the statment that spring compressors are needed.

    1) NO spring compressors are needed for the replacement of the rear springs.

    To replace springs:

    ********

    KEEP ALL BODY PARTS (IE LEGS, HANDS,ETC) AWAY FROM UNDER THE REAR AXEL ASSEMBLY

    ********

    1) jack sided to be replaced up and place on jack stands, remove tire
    2) place small bottle jack (hydralic jack) under rear section of trailing arm (allow enough space for the spring to decompress) I use the area near the end where the bolt spring bolt is attached ---but leave room for a wrench
    3) remove either the top or bottom shock mounting bolt (bottom is prefered) (adjust bottle jack so the shock is not under tension)
    4) slowly lower the bottle jack to remove compression from the spring
    5) when the top of the spring comes away from the top cushion the spring is loose (Check by moving about)
    6) remove the lower spring mounting bolt (place liquid wrench on it once you remove the tire that way you will not sheer it)
    7) NOTE how lower spring pigtail is oriented, remove the spring by either pulling out or treading out.
    8) insert the new spring and attach the lower mounting bracked (leave it just loose enough so that the bottom of the spring can seat as tension is applied)
    9) jack up the trailing arm making sur that the spring seats its self on the top
    10) reattach the shock and tighten down
    11) lower bottle jack and remove
    12) tighten the lower spring mounting bracket bolt and check that the spring is seated correctly (like it was before you monkeyed with it)
    13) remount tire and remove jack
    14) tackle other side

    Time to replace springs 1 hour

    good luck.

    Steve -

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    Questions about 242GT springs.

    Date: Thu, 30 Nov 1995 17:59:50 -0800 (PST)
    From: tim@sr71.arc.nasa.gov ((28.8)Timothy Takahashi)
    To: swedishbricks@me.rochester.edu, "J. M. Reiter" (kassad@u.washington.edu)
    Subject: Re: 242GT Spring Question
    Joel writes :

    >I've been able to track down a set of 242GT springs (all four corners)
    >at a local car yard for a reasonable price and the following questions
    >come to mind:

    > + how much stiffer are they really? I seem to remember someone saying
    > they were 35% stiffer but I can't remember for sure

    The front springs are indeed 35% stiffer, the rears look completely normal.

    > + is there some way to test the springs to assure their lineage?

    Should be visually thicker up front.

    > + should I try to get the GT sway bars at the same time or will the
    > bigger ipd units be better performers?

    The stiff front springs are matched with a set of R-sport antisway bars. 21mm in the front and 23mm in the rear in 1979 (the 1978 cars have smaller bars). The iPd setup has a 25mm (1") in the front and 22mm (7/8") in the rear. The different sway bars give different handling characteristics.

    I would describe the 242gt setup as having higher limits, and a more neutral handling balance, but with more body roll than a set of stock springs with the iPd bars. The reduction in understeer (due to the big rear bar vs. a big front bar) is important to me....

    > + for the GT drivers in the crowd, if I pay below $200 for all four
    > springs do you think my bang/buck ratio greater than one?

    $200 for the R-sport (1979 242GT) suspension kit (front springs + both sway bars) gives a similar increment of performance change as $200 for iPd sway bars.

    One thing I would not reccomend is the R-sport front springs PLUS the iPd sway bars.... much too much front roll stifness will make for a flat cornering car, but with significant limit understeer.

    -tim
    ---------------------------------------------------------------------------
    Timothy Takahashi EMAIL : tim@sr71.arc.nasa.gov
    M/S 247-2 (AA/AAL) PHONE : 415-604-4976
    NASA Ames Research Center U. Rochester Alum
    Moffett Field, Ca. 94035 & Swedishbrick Enthusiast

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    What do the ball joints do and what are the symptoms when they wear out?

    Subject: Re: Two "Newbie" Questions
    Date: Wed, 3 Jan 1996 15:52:15 -0800
    From: mjue@infoseek.com (Michael Jue)
    To: Alec Isaacson , Swedishbricks@me.rochester.edu

    At 4:31 PM 1/3/96, Alec Isaacson wrote:
    >I feel kinda embarassed here, but I have to ask.

    >What do my '84 760 turbo's ball joints do, what are the symptoms when
    >they wear out, and what causes them to wear out?

    Ball joints are typically what they sound like: a metal ball pressed into a socket, usually filled with grease. A ball joint is used to join together two moving components that don't necessarily move in the same direction, hence the ball design to allow for compound movement (other than just up-down or side-to-side). In your case, the ball joints in question connect the lower "control arm" to the bottom of your strut housing. The control arm is an up-down motion as it pivots about [usually] two connections to the frame/subframe. The strut housing moves up-down (in tune with the spring/shock assembly) and pivots with the direction of wheel travel.

    As you can imagine, throughout the life of the vehicle, the ball joints are subjected to much abuse despite being "encased" in grease. Because Volvo (and many other) designs specify "permanent" lubrication joints (that is, no fittings for periodic relubrication), the grease does eventually wear down or leak and what you are left with is metal-metal contact. It's this friction that wears out the components.

    What you can expect from worn ball joints:

    o       Steering looseness (slop)
    o       Vibration
    o       "Clunking"
    o       Inability to retain alignment settings
    o       Unstableness at highway speeds
    o       ...and virtually any sensation "out of the ordinary"
    

    In other words, it's hard to isolate as any of these could be attributable to any number of other worn/broken components such as shocks, bushings, springs, etc.

    The only "sure" way to check and/or eliminate ball joints as the cause of the maladies is to disassemble them and measure them with calipers, micrometers, or whatever you have that will measure down to thousandths. Just like brake rotors, there is a certain amount of "runout" that can be tolerated until it's time to actually replace them.

    Fortunately, ball joints are amongst the easiest of the front end components to replace.

    Hope that helps.

    Drive safely,

    Mic
    '87 744T - 178k
    VNCC Member #26

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