C2 rear suspension problem

[Stan E.]

When I mash the throttle on my C2 Duntov 300 HP,M21,W/3:36 it bottoms out the rear and seems to move over to the right. Could the strut rod bushings do this? Or? Thanks for your imput.

[Duke W.]

Re: C2 rear suspension problem

...not a lot here to work with. It could be almost anything associated with the rear suspension, including the tires.

You need to get the car up in the air and do a thorough inspection of the spring, bushings, links, U-joints, tires, and measure rear alignment including per wheel toe.

If you can't do this, find a competent alignment shop with four wheel alignment equipment.

Duke

[Stan E.]

Re: C2 rear suspension problem

Duke, Done all of that.

[Bill W.]

Re: C2 rear suspension problem

Stan, Try the quick and easy first. Switch the rear tires side to side. If the car goes the other way you have found your problem. Make sure tire press. is equal also. Give us more info. Bill

[Duke W.]

Re: C2 rear suspension problem

...or swap the front with the rear tires.

What are the rear alignment settings? The rear toe must be checked on a four wheel alignment machine to ensure that the total toe is split evenly between both sides. For example, the total reading could be zero, but one side is plus 1/8", and the other is minus1/8". This will definitely cause the car to yaw under hard acceleration!

As far as "bottoming" is concerned, is it really "bottoming" as evidenced by the rear suspension hitting the bump stops? Using a little grease on the bump stop is an easy test.

The basic suspension design has poor anti-squat characteristics, so it's common for C2/3s to pitch up noticeably on hard acceleration, which is a combination of front lift and rear squat.

The C4 and C5 rear suspension designs have much better anti-squat characterisitics, as does the C1.

Duke

[Stuart F.]

Re: C2 rear suspension problem

It would help to know what tires you are using, i.e. radial or bias ply. Also, we assume you have a posi unit and it is working properly, i.e. do the old gravel shoulder test.

Stu Fox

[Stuart F.]

Re: C2 rear suspension problem

I was reminded that there may be some younger members who may not know what I meant by a "gravel shoulder test". Back in the day when positractions were rare, a quick test drive in a car to determine whether it had posi, and if it was working properly was to position the rear wheels on dissimilar surfaces, i.e. one on the shoulder of the road and the other on the road. Then with a tempered burst of off line acceleration, you check to see if the left wheel kicks in to help the right wheel which is spinning in the gravel or does it just go along for the ride (typical of an open rear end or a failed posi).

Trust this will explain what I meant, but perhaps someone else can explain it more technically than this old backyard mechanically inclined fart.

Stu Fox

[William C.]

Re: C2 rear suspension problem

Worn stub axle in the differential will also cause the problem if it always goes in the same direction on acceleration, check the in-out travel of the stub axles.