So as step one in an overall suspension R&R for my 88 S4, I've replaced the dampers (front and rear), all rubber parts in the coilover assemblies and replaced the front suspension lower ball joints. Most of the fasteners were replaced, and all fasteners were torqued to spec per the WSMs. We followed the WSM procedures (not that they are all that verbose) and literally double-checked all the observed torque specs on all fasteners.

The lower ball joints are new Porsche branded items. The dampers are new Sachs (replacing OE Boge). All the replaced rubber parts in the coilover ***'y are new Porsche-branded parts. OE springs were in good shape and re-used.

I have not yet touched the upper A-arms (I intend to do an engine out R&R this fall, and it's much easier to replace the uppers when the engine is out).

With new lower ball joints, the car has a completely random alignment — so obviously I need to deal with that, and I am aware of the need to let the suspension settle before alignment.

Here's the issue for which I'm seeking advice: when I drive the car slowly around just to test that everything is behaving, I have noticed a sensation almost like 'scrubbing' when making a turn. It's hard to describe, but it a very slight sensation in the steering similar to what you would feel with a car that has really tight turning radius pushing against the tires -- where the tires are occasionally scrub against the steering angle for an instant and then seem to 'spring' back onto track.

The incident of this is infrequent, and seems to be only while turning. The car tracks perfectly straight when pointed in straight. To be cautious, I have driven it enough to see if there's a trend (other than while turning) to when it happens.

Do we think this is just a result of random (i.e., no) alignment, or is it indicative that we've assembled something improperly?

Obviously I need to drive the car to get it to settle, but I want to make sure I'm not going to break something.

 

I'll be interested in responses as I've just done the same thing, and got the same results. Tyres scrub on full lock turns, I've not had an alignment done yet but set the lower ball joint eccentrics to the same position as the old ones.

 

Until the normal ride height is restored, you can't say how it will ride. Ride height affects all the alignment parameters. Toe could be off significantly as a result of the lower balljoint replacement, but depending on how you did the damper swap (such as removing the lower control arm from the body mounts), camber and caster could be off, and ride height as well, if you were not careful to get the compressed spring length the same as before. I measure the spring length before and after swapping them onto new dampers, so as to preserve the original ride height. You can drive the car 75-100 miles or pull the suspension down, with some variation on the procedure described in the shop manual, to settle it and verify your ride height. Many alignment specialists insist on jacking the car up to do their own inspection of the suspension components. If so, you either have to drive the car again or have them pull down the front suspension to settle it to your known ride height before doing the alignment. I have verified that it does take 75-100 miles for the front suspension to settle (mine dropped about half way after 35 miles). The rear settles immediately, not having the same lower control arm bushing arrangement as the front. I've also verified with ride height measurement that pulling the front down by the swaybar while on alignment plates can get the front settled back down after jacking.

 

You need to have a wheel alignment done before you can fault find other issues.

 

"Eccentrics set to same..."

As they were on worn parts.

 

I was wondering, did you follow the WSM on tightening the rear LCA clamps?
Otherwise follow Bill ***** suggestions

 

I'd go after a few adjustments right away, at least camber and a rough caster adjustment. These are a bit interactive thanks to the way the lower balljoints connect to the control arm with the two cams.

Caster is the angle of inclination fore and aft for a line through the lower and upper balljoint centers. For the S4, you'll end up with the caster adjusted pretty close to minimum. So adjust the CASTER cam so that the balljoint is as far to the REAR as possible. Do both sides.

Camber is the angle of inclination side to side for the WHEEL. The top of the wheel is closer to the centerline of the car than the bottom. Using a carpenter's bubble-level and a couple same-thickness spacer blocks against the rim edge, use a couple bungee cords to hold the level and the blocks together, with the blocks sitting on the rim edge top and bottom. I use a drill bit added to the space at the top and some trig to calculate the angles, but for your initial settings you can use a common 3/16" bit and be safe. So the top of the wheel is leaning in, and the drill bit is added between the top of the wheel and the bubble level. Adjust the CAMBER cam until the bubble shows the level is straight up and down. Both sides need to be the same of course.

There are several ways to get initial toe-in set. MK suggests that you use a stick pressed against the side of the tire, and make a paint or magic-marker line on the floor where the stick lands. You get to press on the stick so that the pressure against the tire is even at both contact points, and have the end of the stick on the ground so you can make a mark. Use a yardstick or a longer layout ruler, and put a tape mark on the floor as far as you can comfortably reach with whatever stick length you have available. Put tape down at the same distance ahead of and behind the center of the wheel, where the end of the stick will land. Make marks on the tape where the stick lands on both pieces of tape. Do the same on the other side. Your goal is to have the two front marks a little closer together than the two rear marks, for toe-in. These are rough settings since the toe will change (go towards toe-out) as the car settles. I'd start with somewhere around 1/4" difference with the tape marks 30" apart (15" in front of and 15" behind the wheel center) on each side. Go drive the car some, then come back and measure/adjust again. After the car has done its initial settling (first ten miles or so) the 1/4" difference will save the inside edges of your tires from scrubbing off as you put the rest of the settling miles on it.

During this settling time you'll probably be tweaking the ride height adjusters so the cars settled height is where you want it. Since you cleaned and lubricated the sleeves, you'll be able to adjust them without lifting the car again. Height djustments take some 'settling' time too.



Follow the group's guidance and have a good pro wheel alignment done as soon as the car is at your target ride height and isn't changing anymore.

 

If I understand your question correctly, I don't think I disassembled that deep.

Only work on the rear was replacing the damper and spring and the rubber parts in the damper/spring ***'y. Did not remove the control arm to change the control arm bushings at this time — that's a future project. So the rear control arms were untouched, other than removing the bearing pin (through shock and wheel carrier) to free the lower end of the shock. And that pin was reused with new locknuts torqued per WSM.

Did disconnect the rear stabilizer from the LCA for easier movement of the LCA, but after installing the rebuilt damper/spring assy the stabilizer was reconnected (one bolt per side) and torqued to spec.

This project started as a simple shock replacement, and picked up some WYIT items. The rubber parts I was referring to in the original post are just those in the damper/spring ***'y (the coilover mounts, and other vibration isolating pieces in damper/spring ***'y). At the front, WYIT expanded to the lower ball joints, as they were pretty easily dealt with at the same time.

 

Thanks — that seems reasonably straightforward.



I did indeed clean and lubricate those dang sleeves. Tangentially, I gave up trying to get the rear sleeves off of the old dampers and bought replacements at a reasonable price from Mark.


That is exactly my plan. I have already booked an appointment at Stokes Tire in Santa Monica per the advice posted elsewhere here. In fact, my initial question was just this: can I drive it around enough to settle the car to get it there for professional alignment?

Thanks a ton for the help and advice.

 

I wasn't expecting the alignment to be correct by setting the eccentrics as per the old ones, merely not 180° out or somewhere near.
For the torque setting I left front LCA and rear big pin half tightend drove a few times to adjust the ride height to 175mm all around, it settles quicker, then torqued with weight on wheels.

Booked in for a Hunter alignment.

 

Look to the right as you head up the 405 and pick out our former hacienda on the hill, overlooking Glendale and the LA basin. Alignment and other clinics were fairly regular events. Coming up on two years gone, have yet to have any clinics here at the new digs. I'll get to it one of these days.

 

If you do, and there's enough advance notice, I'll try to make a road trip to my house in Astoria via Bend.

Thanks again.

 

ahh my wording may be off,
I was talking about the front lower control arm rear clamps,
these are torqued after the car is driven a mile or so.

so I am not talking about any part of the rear suspensions.

 

Oh, got it. Now I know what you're referring too. In our case didn't touch them. As I said, just did the coilovers and lower ball joints. Those can be done without removing the lower control arm. My plan is to do the bushings and upper ball joints (via rebuilt control arms) at once, as phase two.

For now, I've dealt with the worn out components of the suspension and I will refocus my time resources on fuel lines, flex plate and the non-functioning AC. We'll come back to the remaining suspension work in a few months.

 

FWIW on swapping out the front shocks, if you did significant prying down of the LCAs then its possible that the rubber bushings bonded to the pivots could have been damaged IE sheared off.