90Z51

When I had my 99 FRC aligned everything was great until it came time to set my rear camber. The plan was for about -1.5º in the front and a similar amount in the rear. Well, the right rear was fine and then we moved over to the left rear and were only able to get -.9º with the adjustment maxed out. The only thing that we could think of that would cause something like this is if the bushings on the left side were worn out. The bushings are all the original factory bushings, with about 90,000 miles on them. Looking at the ones on the left side, they don't look particularly bad.

I don't mind replacing the bushings in the rear suspension if that's the problem. I just figured I'd ask here to see if this is a common issue with C5s, or if mine is just odd.

acrace

How much adjustability did you have in the right rear? May be that the rear cradle isn't centered. I had a similar issue (although not nearly that extreme) and Danny Popp adjusted it as part of a set-up.

90Z51

The right rear could easily go to -2, the cam bolt has a lot further it can go. Can you tell me more about the rear cradle not being centered?

96CollectorSport

If the cradle is off an extreme amount you will find that you have much more adjustment on one side than the other.

wtknght1

If it's a 99 and you haven't replaced the bushings yet (and have done quite a bit of track stuff), the rear bushings are certainly worn. But, the camber difference is probably due to the cradle and just differences in the alignment machine and the car's frame itself.

But, if you're going to put -1.5 in the front, I wouldn't put -1.5 in the back. As a general rule, you want about half the neg camber in the back as you put in the front (assuming the suspension and such is still basically stock). Also, when you crank in a bunch of neg camber in the back, you can actually lose some traction coming off the corners (oversteer) because the tire is riding too much on the inside part...so you get wheel spin. As the car straightens out, you want a nice flat tire surface to put down the power. A bunch of neg camber will/can hurt that.

If you're running -1.5 in front, try about -.7 or .8 in the back and see how it does. Tighten those concentric bolts down HARD too!!!!!! Or better yet, call Gary Hoffman at Hardbar and get his camber plates for the rear end and scrap those damn concentric bolts!!

90Z51

Thanks for the rear camber acvice. I could certianly use some extra traction accelerating out of turns.

Is this the kit from Gary that you are talking about?
http://hardbarusa.com/hardbar/produc...products_id=41

Also, is the procedure to adjust the cradle in the FSM?

Thanks.

wtknght1

Yep, that's the kit. He can send you several plates and you can adjust it as much or as little as you need to. That makes it really easy and super accurate!

Adjusting the rear cradle - there are pins that it fits into so you can't adjust it much, but I've seen as much as .5 from just moving the rear cradle a little bit. Do it at the alignment shop so you can see the change from one position to another.

JVetthead

The way I adjust the cradle is to crank both adjusters all the way out, then loosen the 4 cradle bolts and move cradle to the side with least camber.. till camber measures even or close to it...

acrace

90Z51 - if you're saying that one side can go to more than 2 deg neg and the other side is max'ed out at 0.9, it really points to cradle adjustment. I haven't done it (had it done) but did look at it. JVetthead sounds like he's got a good procedure.

davidfarmer

1. Common problem, subframes are rarely centered. The don't really need to be for most cars

2. You don't need more than 1.5 max in the rear

3. GM Camber plates will give you and extra 0.2deg or so in the rear.