I am having a problem with the rear camber bolts loosing under load especially on the track. I end up with severe toe in and positive camber. Is anyone else having this problem? If so what is a good fix?

Blair

 

Before every race or autocross torque down those bolts to
150 ft-lbs.

Another thing people have done is get the super high temp high strength loctite and put it on the threads, then tighten down to 150 ft-lbs.

Regular loctite wont do the job.

Alex

 

Yep, had the same problem. Service manual says something like 85ft-lbs for those fasteners. I started upping the torque until they held. It took 125ft-lbs to keep them in place for me.

The issue wasn't so much the nuts loosening, it was that the forces from the rear suspension were overcoming the clamping force of the nut/bolt.

I marked them once I get the camber where I wanted it, so if they ever move I'll know right away and can put them back where they were.

 

Thanks for the advice guys but as I see it there is a flaw in the "system" Has anyone brought this to GM's attention. I thought maybe the bushing was compressing thus letting the bolt come loose just long enough to allow the problem to happen.


[Modified by myyellowZ06, 11:15 PM 7/12/2002]

 

Actually,

its because of the cam bolt. When you dial in max negative camber at the rear, the cam bolt is towards the outside. The range of travel in normally has is an arc. From the factory, it comes at the top of the arc, and in this position it has the most resistance to sideways forces. When you max the camber out, you are putting the cam bolt in the worst position for side to side forces to act upon it and move it.

Usually, you can get much more camber on the right rear of the car, so that cam bolt usually gets adjusted far from totally towards the outside, while the drivers side rear cam bolt is usually maxed out (for racing applications).

OF the cam bolts that Ive seen come loose, its always the rear driver side one because of the above.

Even at 150 ft-lbs of torque, I find I have to re-tighten them often.


BTW, GM knows about this and the wandering front control arms, but wont do anything about it because the community of people that actually race their cars is small (ie, to do a production wide change would take big bucks). GM is not willing to spend the money.

Alex

 

That's exactly what I do...

 

I think the torque is 147 on the front and 107 on the rear bolts.

Can someone confirm?

I had this same thing happen before I got the torque specs correct. No problem ever since. Cross my fingers!!

 

So far I have been lucky enough to have the problem fixed (twice) by the dealership. I believe the car is most fun when pushed to the limits at lapping days (non competion :) but it sure is a pain fixing it all the time. Also what brake pads are people using when they decide to "push the car" I still use the factory pads and rotors but get extreme brake dust on the wheels. Even just driving the car on the street my front rims are never clean for more than 60 ft.

 

We had this problem right out of the box last year and by my best recollection the factory spec is approx. 106 ft-lb front & rear (bolts are the same size). We torqued to 120 ft-lb (freshly calibrated) after that and never had it happen again. I'm a bit shocked to hear 150 ft-lb being used, that's significantly over the OE spec. Would be concerned with the bolt stretching and loosening over time. It's pretty much a 2 person job to do it right; one person to hold the std. wrench on the bolt head and keep it from rotating and the other person with the torque wrench on the nut tightening it down. They'll come loose on the front too, so best to tighten them all. Use a parts paint marker to make an alignment mark from the cam head to the subframe, this will serve as an indicator to check for cam head movement.

Also, not only does the rear wheel go positive camber but it will toe in big time on that side. You'll have to string the car or do a 4 wheel alignment to get the chassis squared up again. If you have the paint mark like I suggested you can at least get it adjusted close enough to get by in an emergency situation, like in the middle of competition.

Regarding the lower front control arm bushing situation, don't bother with fixing it. The bushings will just do the same thing again and the front wheels will keep toeing in significantly during the settling process. The fix as I see it is to use hard plastic spacer (delrin, uhmw, etc.) bushings between the control arm and the subframe, but this wouldn't be considered legal for many motorsport classes unless specified by the manufacturer.

Mark

 

Mark,

I read in a 99 Coupe's Service Manual 127 front 107 rear give or take a couple of foot pounds.

I asked the question on the forum and someone responded in the 140 range front and 107 rear.