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Discussion Starter #1
Now that this 94 FWB I'm working on has had the control arms replaced and a proper alignment I can start looking at other issues with the suspension and steering.

Ever since we've had this car we've noticed that the steering's tendency to return to center is very weak and after a certain point reached early in turning the wheels is basically non-existent. Now that the suspension is aligned to spec, it hasn't gotten any better. I don't remember whether this was the case with the one I drove not many years after it was made - is this normal for the platform and if so, is there anything other than a non-factory-spec alignment to be done about it?
 

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I'd be leaning toward a steering box adjustment at this point. Maybe a steering damper issue?

http://www.impalassforum.com/vBulletin/17-suspension/803217-steering-returnability-after-new-ball-joints-experts-needed.html

Did they/you replace the nuts that secure the upper control arms and may have been loosened during the Alignment process? If not, check that they did not back out and you lost shims. These nuts really should be replaced as part of the alignment. They loosen up after a use or 2 and won't hold their position and keep the shims from falling out.
 

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The stock settings for the caster is probably the issue. You can increase the caster by removing shims from the front stack, and adding the same amount to the rear on both sides. Moving 0.030 (1/32 inch) from the front to the back will give you almost 1/2 degree of increased caster. It will not upset the rest of your alignment, although you could have your toe checked just to verify that. There is a thread about improved alignment specs on the forum. Often there are thick shims in the stack, and you can put thinner ones in, and/or move them from front to back to achieve your desired settings. Measure, and write down the size of the stack and keep the shims together, so you do not mix them up, or forget what the original was, in case you want to go back to that. A little dab of different color paint on each stack of shims, also helps identify the original location. Most of the shims have the size stamped on them, but you should have a calipers, or micrometer to measure them just in case.


The return is generally weak on the B and D body cars, and the caster determines the desire for the wheels to return to straight. The more you have the more you get.
 

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You mentioned you had an alignment done, and you don't appear the type to have used a 'toe-n-go' chain.

That said, I'll offer my FWs have had the squishiest and most vague overall steering of any car out there, including my wife's Tribute!

Now years back when trying to cure cloverleaf jerkover I did not feel appreciable difference when unplugging the Variable Effort boost potentiometer, thus sending system into fulltime/full boost (it's at the firewall). There's a very detailed thread on the differences between CHEV-Buick-Cady pumps (Joel?), and for a car that's already had previously "wrong repairs" it may be yours had an incorrect replacement.

Not much else except box and caster points above.
 

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Discussion Starter #5
I'd be leaning toward a steering box adjustment at this point. Maybe a steering damper issue?

http://www.impalassforum.com/vBulletin/17-suspension/803217-steering-returnability-after-new-ball-joints-experts-needed.html

Did they/you replace the nuts that secure the upper control arms and may have been loosened during the Alignment process? If not, check that they did not back out and you lost shims. These nuts really should be replaced as part of the alignment. They loosen up after a use or 2 and won't hold their position and keep the shims from falling out.
The nuts were checked before and after and were still nice and tight. The problem existed before the alignment as well.
 

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Discussion Starter #6
You mentioned you had an alignment done, and you don't appear the type to have used a 'toe-n-go' chain.
Yes, I used a local specialist shop - all they do is suspension and brakes.

FYI, the newer alignment rigs are no longer able to align the FW or the equally-fender-obscuring-tire early B-bodies. The newer laser alignment rigs do not fit under the rear fenders and require special adapters in order to work - which most shops didn't purchase.

That said, I'll offer my FWs have had the squishiest and most vague overall steering of any car out there, including my wife's Tribute!
Yeah, I've driven worse but they're usually older American rigs from the 70s.

Now years back when trying to cure cloverleaf jerkover I did not feel appreciable difference when unplugging the Variable Effort boost potentiometer, thus sending system into fulltime/full boost (it's at the firewall). There's a very detailed thread on the differences between CHEV-Buick-Cady pumps (Joel?), and for a car that's already had previously "wrong repairs" it may be yours had an incorrect replacement.
We already unplugged the potentiometer and got a noticeable improvement.

Not much else except box and caster points above.
One thing we're looking at doing is replacing this Saginaw box with one from another car that doesn't have variable ratio and does have better feel/feedback. It's looking like one from a Jeep ZJ Grand Cherokee is the best candidate, but that's something for another time.
 

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Discussion Starter #7
The stock settings for the caster is probably the issue. You can increase the caster by removing shims from the front stack, and adding the same amount to the rear on both sides. Moving 0.030 (1/32 inch) from the front to the back will give you almost 1/2 degree of increased caster. It will not upset the rest of your alignment, although you could have your toe checked just to verify that. There is a thread about improved alignment specs on the forum. Often there are thick shims in the stack, and you can put thinner ones in, and/or move them from front to back to achieve your desired settings. Measure, and write down the size of the stack and keep the shims together, so you do not mix them up, or forget what the original was, in case you want to go back to that. A little dab of different color paint on each stack of shims, also helps identify the original location. Most of the shims have the size stamped on them, but you should have a calipers, or micrometer to measure them just in case.


The return is generally weak on the B and D body cars, and the caster determines the desire for the wheels to return to straight. The more you have the more you get.
That doesn't sound like a particularly fun way to adjust caster... What's the stock alignment caster spec?
 

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That doesn't sound like a particularly fun way to adjust caster... What's the stock alignment caster spec?
I agree with fred . they did not do the caster properly or at all.

toe and go ! thats what IMO they did. I doubt they even have the shims .

I do my own alignments did the first one back in 1996. had a right drift . also had to set toe vehicle drifted too much tires must point in not out .......it does not take much ...

when I replace my tires all 4 look exactly the same ... the passenger side is a PITA.
 

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I picked up a lightly used camber/caster gauge a few years ago, on ebay, for about $66. It has the magnet mount for the hub. I can set my camber and caster at home. I also made a set of toe gauges, and they work with a couple of tape measures. The camber/caster gauges have paid for themselves a few times over. After the first alignment, they are free. A good, and I mean complete, alignment costs about $130 here in FL. I can do the same quality of alignment in my driveway.
 

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Spec caster is 3.5 degrees. The "improved" setting is 4 degrees. The difference is 1/32 inch shim removed from the front, and added to the back stack.
 

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Discussion Starter #11
I agree with fred . they did not do the caster properly or at all.

toe and go ! thats what IMO they did. I doubt they even have the shims .
Ummmm, pretty sure they did have the shims, as I saw them personally. Also, this was an old family firm that is known to specialize in older vehicles and 'problem' alignments. Put another way, this shop still has headlight aiming apparatus and alignment gear dating back to the 1950s in addition to modern laser gear.

Also pretty sure they did all three - camber and toe were visibly far out after replacing three out of four front control arms when we sent the car over; they corrected that, which would not be possible with toe-n-go. The car was in alignment before the suspension work and the problem was evident before we spun a single wrench.
 

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Discussion Starter #12
Spec caster is 3.5 degrees. The "improved" setting is 4 degrees. The difference is 1/32 inch shim removed from the front, and added to the back stack.

Wow... that camber spec is pretty crap. Little wonder the return to center is so poor. I know they were trying to reduce steering effort on these cars, but that's ridiculous.

What's the maximum adjustment range for this system?
 

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Ummmm, pretty sure they did have the shims, as I saw them personally. Also, this was an old family firm that is known to specialize in older vehicles and 'problem' alignments. Put another way, this shop still has headlight aiming apparatus and alignment gear dating back to the 1950s in addition to modern laser gear.

Also pretty sure they did all three - camber and toe were visibly far out after replacing three out of four front control arms when we sent the car over; they corrected that, which would not be possible with toe-n-go. The car was in alignment before the suspension work and the problem was evident before we spun a single wrench.
typically in today's world of alignments they give a spec sheet before / after......

so compare these # to what they did. caster left 3.25 deg caster right 3.75 deg
Camber left and right 0 degrees

TOE .o8 degrees total TOE .16 degrees steering wheel angle 0 degrees..............

this is from the GM manual .

If I did this changing on all the front end parts I would put back in the shims as they were. I would set the toe so it is a bit more on the toe .

as the springs and rubber components take a set after about 1000 miles then recheck the alignment .

Now if an alignment was done to correct damaged bushings / parts [bent] then you will need 2 alignments one after the work then 1000 miles later.

That's my IMO...
 

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I am looking at the alignment chart in my FSM, and the camber is supposed to be +0.8 deg. and neutral caster is 3.5 deg. Both of these are + or- 0.5 deg. Toe is +0.16 deg., and plus or minus 0.2 deg.


To adjust for the crown of the road, you can put more caster on one side. A quarter of a degree of camber will achieve the same results and still be within specs. I did not specify which side, because some of our readers are from countries who drive on the left side of the road, and would do the opposite of those who drive on the right side. 1/2 degree more total caster will not hurt the performance of the steering.
 

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I am looking at the alignment chart in my FSM, and the camber is supposed to be +0.8 deg. and neutral caster is 3.5 deg. Both of these are + or- 0.5 deg. Toe is +0.16 deg., and plus or minus 0.2 deg.


To adjust for the crown of the road, you can put more caster on one side. A quarter of a degree of camber will achieve the same results and still be within specs. I did not specify which side, because some of our readers are from countries who drive on the left side of the road, and would do the opposite of those who drive on the right side. 1/2 degree more total caster will not hurt the performance of the steering.
slight differences with your manual .. the GM HELMS is what I have . camber is zero .that is how I set them tires wear perfect .
 

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Discussion Starter #16
typically in today's world of alignments they give a spec sheet before / after......
Yes, they did. It promptly got lost in the papers on my desk and I haven't found it since.

If I did this changing on all the front end parts I would put back in the shims as they were.
This was done at the time we put the suspension back together.

as the springs and rubber components take a set after about 1000 miles then recheck the alignment .
Wasn't aware that was a thing on this suspension - we'll keep that in mind.

Now if an alignment was done to correct damaged bushings / parts [bent] then you will need 2 alignments one after the work then 1000 miles later
The latest alignment was done after replacing the control arms with bushings and ball joints completely. We'd had one done when the car was first purchased.
 

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Yes, they did. It promptly got lost in the papers on my desk and I haven't found it since.



The latest alignment was done after replacing the control arms with bushings and ball joints completely. We'd had one done when the car was first purchased.
doing an alignment with the parts worn out, now it explains the wheels being so messed up after the new parts installed .. yes this alignment changes as the springs take a set . and other parts .

this is something I have done since 1967 on this type GM platform .. after about 1000 miles I have to tweek the alignment , then the way I drive I rarely have to re do it.. I also grease every 6 months ..
 
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