Can't hold camber

[Campbell]

Hi,

I need some suggestions on what to do next, I race an ITB Scirocco (84) and I try to keep 3.5 neg camber on the driver front. I would always start the weekend that way and as the weekend progress the car would push more and more. When I would get home I would find the camber less than 2 neg. So for this weekend I drilled a 3/16" hole 1/2" into the strut/knuckle assembly between the two camber bolts and put in a 3/16" pressure pin to keep the camber locked at 3.5 neg. Well the car drove okay - but when I got home the camber was down to 2.5 neg!! it appears the knuckle arm didn't move at all in the strut bracket. The top of the strut (camber plate) didn't move either. Do you think it is a bent control arm? ball joint? (my ball joints are riveted in). How do I check or do you have any other suggestions. Thanks

[Knestis]

You don't say specifically but if you are using narrow-shank "crash bolts" to adjust your camber, is it possible that the pin you put in is simply acting as a pivot, around which your upright/strut connection is rotating? Is it possible that you whacked the front corner enough to bend the upright casting?

Kirk

[Joe Craven]

Check your inner control arm bushings, ball joint, etc. for play.

[Bill Miller]

Well, here's my take. The first thing you need to do is get new ball joints. If the ones you have are riveted in, they're the original ones that came on the car when it was new. That means they're ~ 20 years old!

Now, to your camber problem. I always try and make sure that I check the camber w/ the car in the same spot all the time. The key is, the car needs to be level. Another thing you need to do is 'bounce' the suspension before you check it, to settle everything. You also need to make sure the wheels are pointed straight ahead when you take your readings.

I seriously doubt it's a bent control arm, as you probably wouldn't be able to get it to where you wanted it to be to begin with. Plus, that wouldn't account for the change in reading. You can put a staight edge across the control arm to see if it's bent. It certainly could be a bad ball joint (see above comments).

If you're able to get -3.5 deg. of camber out of the thing, you've got to be using crash bolts already. Most I've seen w/ a stock setup is -1.75 deg.

Now, are you sure you have the eccentric washered bolt in the right hole? Is it on top?

Before I started drilling holes in the knuckles, etc., I'd use some paint/nail polish/etc. to paint 'joints' to see if something was actually moving.

Lastly, are you sure of the repeatability of the readings of your camber gauge? We chased a similar problem on a short track car, and tire pressures. We had two gauges (both Longacre), but it turned out one was off by 5#! Makes a big difference when you're running in the 20# range.

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MARRS #25 ITB Rabbit GTI
SCCA 279608

[Campbell]

I think the camber gauge is stable and I check the camber in the same spot, in the same way to try to have good repeatability. I'm not sure what a crash bolt is.. I use two of the bottom bolts and can get extra camber because I elongated the top hole. I also use washers the size of the bolt head to maximize adjustment. It doesn't seem that anything slipped, I will check it again with bouncing though although that is not something I normally do. I haven't messed with ball joints before is there a way to check them? I try moving the tire and it is tight on the knuckle assembly with just a little wobble where the Bilsteins come out of the strut housing. I will check and see if the a arm is straight. I didn't hit anything this weekend although I do go off track once, hit someones rear bumper skin and got back on the track without any hard bouncing or smacking. I am stumped, 1 degree of camber is a lot to lose.. thanks for your thoughts.

[Campbell]

Oh, to replace the ball joint that is riveted in do I break or drill out the rivets or get a new a arm? I take it the new ball joints would fit in the rivet holes okay? thanks

[racer_tim]

If your using the bottom bolts, without the ecentric one on top, most likely the strut is moving around the top bolt. You'd be suprised hoe much force is exerted on the strut assembly.

Go back to the stock ecentric bolts in the top strut mounting holes. The are eleptical for a reason.

Or, somehow eliminate all the adjustment in the upper strut bolt assembly, and adjust by the camber plate.

Just drill out the rivets and install the new ball joints with grade 8 hardware, with self locking nuts.

I don't think that your seeing your variances in the ball joints, but like Bill said, they are pretty old. I know, if it's not broke, then don't fix it, but racing puts lots more strain on suspension parts than just driving around town.

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Tim Linerud
San Francisco Region SCCA
#95 LP GP Wabbit
http://linerud.myvnc.com/racing/index.html

[This message has been edited by racer_tim (edited May 26, 2003).]

[joeg]

I tried "locking" the top of the strut without a proper camber plate and bent the strut.

Lots of force up there!

[Bill Miller]

Well, I have to agree w/ Tim on this one. If you're not using the 'correct' upper strut bolt (the one w/ the captured eliptical washer on the bolt end, and another eliptical washer on the nut end, you're going to get movement. Those washers are there for a reason, to provide interference so the strut housing can't "slide" against the knuckle mounting point.

"Crash bolts" are designed to give more adjustment, and are named such becuase you need more adjustment to correct the results of a 'crash'.

On VW's, I'm a much bigger fan of putting proper camber plates in at the top than I am of elongating the top sturt mounting hole (where it attaches to the knuckle).

As far as the ball joints go, yes, you drill out the rivets. What I do is drill out enough of the head so that I can cut it off w/ a chisel, and then use a punch to drive the rest of the rivet back out of the hole. Most new ball joints should come w/ bolts and lock nuts.

I don't know what you're running for control arm bushings, but if you're running the stock, rubber ones, you may want to consider a new set of control arms w/ Delrin or urethane bushings. That way you can just bolt up the new ball joints and not worry about drilling out the old ones. Take the old control arms and put them in your parts box for spares. But, I would still suggest changing those ball joints as they're 20 years old.

Another question I'd have, is how often are you changing front hubs? This is a known weak point w/ VW's, especially A1 chassis cars as they have the smaller diameter hubs/bearings. As a rule of thumb, I change these ~every 6 races. They do fail, and I figure it's cheaper to change them out than have one fail. I just have a spare set of knuckles that I have fresh bearings/hubs in, and when I change them, I just get new stuff pressed into the old ones.

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MARRS #25 ITB Rabbit GTI
SCCA 279608

[Campbell]

I only have 2 races on my current hubs - I change them evey 8 races and have a back up set like Bill has. By drilling and pinning the knuckle arm into the strut bracket there isn't any play - Looking at it it appears there hasn't been any shifting or movement at all. I set the bottom to give 3.5 degrees with the top (in a camber plate) right in the middle so I could add or decrease camber as needed from the top. Gosh I think something bent due to the pounding it takes on that corner. The other side remained unchanged through the weekend at 1 3/4 degrees (I pinned it as well). Nothing seems obvious, isn't that the way it always is!! thanks

[Campbell]

Well I have taken everyones advice and got a new control arm and ball joint from BSI. I pulled off my old control arm and it has a urethane? hard white plastic like material with a metal tube in it in the front and a white plastic rear bushing. I want to reuse the front bushing but don't understand how it was installed (I bought the car already built). Are they one piece? it is larger than the housing on each end - how do I get it out? any help would really be appreciated!! (and is really needed) thanks

[Mark LaBarre]

They are a 2 piece set up. One is inserted from each side until it hits the larger collar. They probably wont come out without a big fight. Try carefully cutting the sleeve on the arb apart with a die or side grinder.
Mark

[Campbell]

Thanks, I was able to get the bushing out - it was a two piece unit, they turned out with channel locks. Putting the new arm on took a little longer than I thought, it is a really tight fit on that front bushing. When I drop the car I will check the camber but I don't think the control arm was it.. but I think it was good to change it and the ball joint anyway.

[Bill Miller]

From what you've described, you already had Delrin bushings in the control arm. I also doubt that it's the control arm. It may be the ball joint, but probably not the control arm. I'd still look to the pinch bolts on the strut as the cause.

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MARRS #25 ITB Rabbit GTI (sold)
SCCA 279608