TD in DC

At my last track outing, I heard a noise from the right rear of the car, and it now appears that the right rear tire has a greater negative camber than the left rear tire. Is it possible to adjust the rear camber without affecting toe, or should I just give up and take it to an alignment shop?

Also, are there any good step by step resources on how to align the rear suspension of a 944? Thanks.

924RACR

Do you have the toe adjustment tool? Even with, it's challenging.. BTDT. The rear suspension is miserable to deal with. Do you have a camber gauge and toe plates or the like?

Skip Wolfe

Yes.

As 924RACR stated, the rear suspension is tough to get right. Local Porsche race prep shop charges $240+ for a 4 wheel alignment and the McPherson front setup is a piece of cake (I can do it with toe plates and a camber gauage) so most of that labor is for the rear.

TD in DC

Nope, I got nothing. OK, thanks for the advice.

What could cause one side to increase camber like that? Is this a frequent problem? Oddly, I heard the noise in a high speed right hand turn (T9 at Summit Point) and it is as if it happened when the rear passenger side was dragging across the pavement . . .

Carrera GT

Have you checked the torque on all the suspension adjustment fasteners?
If you've had an alignment done recently, you should be able to have them re-do the car for a nominal fee.
For what it's worth, the triangular structures of rear multi-link suspension mean caster, camber and toe will move in concert: caster will change camber, camber will change toe.
If your car is basically okay and you're on a budget, you can reset the camber to "match" the other side, then reset the toe using string.
You can buy the adjuster nut pretty cheaply from any of the Web sites with Porsche stuff (choose a Rennlist sponsor ...) or your local dealer can get it pretty quickly if they don't happen to have one in stock. If you also don't have the wrenches, well, forget it. : )

Oddjob

The toe and camber really need to be set at the same time. I would say that if you try to adjust the camber only, without readjusting/checking the toe, you probably changed the toe without knowing.

The only thing that would cause the rear camber to change significantly (enough that you can see with the naked eye) is if the adjustment bolts were loose; or if you hit something hard enough that it moved the suspension (like driving over a curb); or if a suspension bushing failed, but that would have other symptoms too.

If the camber did get thrown off, I would also assume that the toe went south also, so you really should get it checked by an alignment shop.

There are ways to do-it-yourself, home alignment jobs, but you really need to start off with a known alignment spec. As in: if I know the car has -2.5 deg camber, and I want -2.8, you can do that in the garage (but you have to watch and screw around with the toe also - so its a pain). But if I want -2.5, and I have no idea what the camber is currently set at, and I dont know if the toe is correct or not - no way to easily do that at home.

Carrera GT, the old 944 guys dont have the 993 type multilink rear suspenison, so no caster adjustment on the back - thank god.

M758

rear toe is critical on these cars. Too little and you can spin easily under braking.

As for the toe adjuster.. I bought one, but found it hard to use on my lowered car. I could not get enough toe-in from it. So I adjusted stuff without it.

Probably best to take the car to a shop and have them do a proper corner balance and aligment. PM me if you want to some settings to use.

Oddjob

The little toe tool does work ok for mid-range alignment specs, but I agree that its limited when going extreme for the track setups; it just doesnt work that well.

Getting toe-in with a lot of neg. camber is hard. Ive found that its nearly impossible to get 0.10 deg or higher toe-in with anything near or above -2.5 deg camber.

I had to use a tie down ratchet strap to pull the control arm forward (to set toe-in) to get the toe I wanted with the camber I wanted. Anchored the ratched strap to front bar of my roll cage (with door open) and to one of the wheel studs on the trailing arm, and started cranking away - finally pulled the trailing arm forward enough to get some toe-in.

924RACR

Agreed - some good tips on the toe-in tricks! I'm getting the toe-in I need with the tool, but only just barely... think I have maybe 1/4" total (as measured with my toe plates), but both adjusters are maxed out.

TD - I wouldn't be surprised if you had some bolts that sprang loose, allowing your settings to slip. No doubt the car felt like A$$ once that happened? I've made that mistake before. I find that while I can get it straight and where I want on an alignment rack, I can't get access to the bolts (from below) enough to tighten them completely; I have to remove the tire (thereby removing the alignment head and eliminating my measurements) and hit them with an impact (carefully!).

Wrenches required - I like 2 19mm wrenches, the toe tool, 24mm wrench for the toe tool, 27mm wrench for the camber eccentric. Also add another 24mm wrench or socket/ratchet and a 36mm wrench to adjust ride height, if needed. The Paragon set of 4 oil line wrenches has the 27 and 36, plus 30 and 32mm...

TD in DC

It didn't handle that badly, but the timing of the incident was truly unfortunate. I have a provisional NASA racing license. In order to run our PCA Club race, I was told that the easiest way was to get a check out ride during a recent DE. So, I did.

On the first and second laps of the checkout ride, the camber slipped at T9 at Summit Point. On the second lap, I was tempted to pit in (pit in is shortly after T9), but I decided it would be dangerous to try to get over since there was traffic. During a recent DE, I had a front A-arm snap so I have become very, very wary of mechanical failures and I take "noises" and "feelings" very seriously. So, I told the check out driver that I was going to slow way down because the car was not right and that I was going to pit in during the next lap. He said ok. So I back way off and start letting several cars by. I mean, what is the point of holding people up if you are not willing to drive at 8-9/10s and you are planning to pit in, particularly in a n/a 944 in the black group? When we got in, the check-out instructor told me that I was not aggressive enough and he thought that I was too slow for the club race? I protested and reminded him that I told him I had a mechanical problem and was pitting in. He said he was not saying no or yes to me, but that we could ride again, perhaps at the next DE.

I found the situation to be extremely frustrating. So I put the car up on jacks, found what I thought the problem was, and determined that I was not about to have any catastrophic failures. Then we went out again. I wasn't about to wait for another DE. This time, I drove much more closely to my normal style of driving. When we came back in, he told me that perhaps I was too aggressive. I explained that I had driven that way only because he thought I was too passive. In any event, he gave me some good tips and signed me off for the race. If I can get my car fixed in time (bodywork), I will be racing.

I have been considering buying the longacre alignment tools so that I can monitor my own alignment and save on repeated shop costs. Do you guys think this is a good idea, or is it simply too hard to do a good self alignment that it is not worth it?

aribop

Am I correct in thinking the only way to adjust rear camber is by way of the eccentric bolt that effects rear suspension height?

M758

I have a camber gauge and used home made plates to set toe. Works pretty well. I have hard corner balance once at shop and once a friend who had scales. That is it in many years of use, but I do check the front end adjust it myself.

In my experience the cars don't change very much. You would be just find a camber gauge and a tape measure for most of the work. Maybe have shop reset everything once every couple years.

Oddjob

The ride height adjustment on the rear spring plate is not the same as the alignment adjustment. The 3 bolts, used to adjust alignment, attach the trailing arm to the spring plate - not the two big height adj. bolts (one eccentric) forward on the spring plates. For the alignment bolts, one is an eccentric and is also the attachment point for the swaybar drop link. The other two are just tightening bolts.

924RACR

I'm happier using my tools at home than the high-end Jim Beam alignment rack I have access to at work. I don't find it does a good enough job with our rear suspension, though it's money on the front.

It takes a while, but with practice you can get decent at it.

Oddjob

How are you guys checking the thrust angle at home?

Also, do you have a trench, hoist, or other means of adjusting while the car is on the ground (weight on the suspension)? Or do you lift the car, make adjustments, then set it back down, let it settle, and re-measure?