I have a base 84 c4, all the bushing look good. I put Z52 Bilstien shocks new tire and 17 inch 90 wheels. It seems to sit too high, rides somewhat bouncy. When I pull the steering wheel back and forth at speed it seems unstable. Could the Z52 shocks be causing some of this? Here is the alignment, it looks off. No negative camber. This other pick seems to be what is all over the internet on what it should be. Any help would be greatly appreciated.

 

I don't have the Factory Service Manual for an early C4, but my FSM for the 96 C4 says it should have 0.5 degrees camber plus/minus 0.5. It's different geometry than your C4, but if the factory spec is the same for an 84 then your current settings are within spec. However, if it were mine, I would want some negative camber in there, but that's for performance reasons rather than road comfort. You're probably right where I'd want my toe settings to be. You could add a teeny bit of toe in up front to make it feel more stable, but overall there is nothing in these settings that should make it feel unstable.

That won't change your ride height, though. Not sure what Z52 shocks really are, but if they are the replacement spec for an early C4 then they shouldn't because causing problems. That said, if your old shocks were blown and had lost all their gas charge, then the car might be been sitting lower on them, and now it's back to new stock ride height.

Did you loosen the control arm bolts where the bushings are? If so, did you set the car back down to regular ride height before tightening them? If not, that could account for the ride height and the unstable feeling. Did you make sure each new shock compresses and extends the way you'd expect before installing? This one seems very unlikely, but a seized shock would definitely cause these symptoms.

 

I got rid of the Bilstein and KB shocks - same issue. I went with Monroe - ride is much better. We have a concrete road that is washboard and it settled the car down.

I lowered mine but run 30 and 40 serries tires,

 

very nice! What springs or products did you use to lower it? Ty

 

OP did you change the springs or remove a bunch of stuff from the engine bay (a/c compressor, air pump, emissions gear)? Doing that could effect ride height. I also like to alignment spec set to 86-87s. Basically doubles your caster and makes highway driving easier.

 

Stock springs nothing removed. Ill get it figured out sooner or later. Ty for asking.

 

This ^^^. I didn't know how much caster is available in the 84-87 C4s, but 3 degrees isn't very much and I meant to suggest bumping it up to 5-6 degrees if possible.

 

The 84s even with base suspension have were some of the stiffest springs..Shocks dampen the action of the spring and by themselves don't support the vehicle
Prior to staggered wheels in 93, 88-92 owners complained about the 275 40s following irregularities in the road surface. It can be similar to driving on expanded metal decking, depending on road. With the alignment I don't care for the right rear not matching the left rear particularly the toe in. The rear is so easy to adjust, toe in should match. In the alignment guys eyes all green is good. How much play in steering when steering? Since you replaced bushings the various arms are to be torqued at ride height. Which is a royal pain with out a drive on rack of some kind. Sometimes there can be enough binding in the bushings it will nit allow vehicle to fully settle. What are the ride heights the arrows for jack on rockers?

 

I did it about 14 years ago.
I used lowering blocks in the front.

 

Generally I agree. However, a few things about toe:

• Unequal toe doesn't do anything except crab the car and put the steering wheel off center. Because the car is steerable, toe always corrects to straight and it can't cause a pull.
• Rather than unequal toe causing instability, it's toe out that causes dartiness and a feeling of instability, especially in the rear. But he has toe in at the rear, so no worries there.
• With 0.09 deg total rear toe in, that's less than 1/16" total toe in, and the difference between left and right is less than 1/64". I don't think there's anything for the OP to worry about here.

 

I don't like the unnecessary crabbing as you call it and it shouldn't be there. The other part is when you do a 4 wheel alignment, the rear is done first. The front alignment toe is based on the rear toe.
Twichyness can be tires, worn steering gear mounts, steering gear, rag joint, or column.im giving the alignment tech the benefit of the doubt the tie rods aren't worn. That is why I asked about play.in steering.

 

Again I agree. However, in the OP's case it would not even be measurable. We're talking about less than 1/64" differential between left and right rear toe.

 

"All green is ood enough is good for you" whatever BTW it is out of spec when you look at Thrust Angle.
Most people will drive cars that are grossly misaligned as long as vehicle doesn't try to change lanes, and some still won't care

 

Negative, Ghost Rider. The thrust angle spec on a 96 C4 straight from the Factory Service Manual is +/- 0.1 degree. I'm sure the spec on an 84 is similar. His measured thrust angle is 0.02 degrees: waaaaaay within spec. If it were five times worse it would still be in spec! And to put this into even better perspective, his thrust angle means that the front wheels are tracking 0.03351" off center with the rears, or about 1/32". That's it. You won't see/feel/detect that in the steering wheel angle or handling of the car at all. There is more variation than that in four tire carcasses. There's also more play in the steering box. There may even be more play in the alignment machine.

To call the OP's car "grossly" misaligned is...grossly misleading. You're making a huge deal about nothing. Again, I agree that the ideal thrust angle is zero, but 0.02 degrees of thrust angle isn't causing the OP's problems, and he would sound insane going back to the shop that did the alignment and complaining about that much thrust angle. He doesn't need to spend time worrying about that.