MK19

Hi,
My '03 SL rear is to be leaning to the right in the rear. I can visually see it and placing a sprit level on the trunk lid confirms what I see. This is the case weather ABC is activated, or if it's been parked for several days (ruling out blocking valve or strut leakage. I've adjusted the height with DAS to 27.5" as measured at the center of each rear wheel arch and it stays there after its parked. Is it possible that the wheel arches are off by maybe 1/2" or more? It has had paint on the LR quarter panel, but there's no indication of any significant repair work either around the edges or from inside of the wheel well (liner removed of course), or from inside if the truck (liners removed).

I imagine the dealers, using the MB body inclination tool might set it up differently, but I'm a few hundred miles from a dealer and I doubt the local Indy's would have that tool as none specialize in MB.

Any insights would be appreciated.

MikeJ65

The rear height calibration is easy and you don't need the special level. You can use any electronic level to measure the half-shaft angles. The front is different because there is not a surface to put a level on. The 'angle' is only defined by the cones of the special tool on different width sections of the control arm.

If the quarter was hung incorrectly, there is obviously no simple correction for the arch height, but the car will look and drive better if the ride height and suspension are at least correctly calibrated and aligned. I would probably take it to a good alignment shop that will work with you and attempt to align it after correcting height. The first step in alignment is checking ride height by the suspension angles. The tech might ignore the instruction or not have the tool, but it is step 1.

g0rsq

Sorry I do not understand this!

Are you saying that both rear arches are at 27.5" to the ground, but the car still leans?

If that is the case then the only possible cause is the bodywork or chassis is not symetrical on each side, so effectively yes one rear arch is off by 1/2" or more!

MK19

g0rsq - its seems as you may be correct. It's certainly possible that the car is either bent, or less likely the factory boy tolerances aren't that tight. But, I've been all over it, and having done my share of paint and body work, there's no apparent damage. As I said, the LR quarter was repained, but it was done so well that I hadn't a clue and only caught it with my paint meter. Deck lid is factory, except for a re-paint if the lower, license plate panel, any damage appears to be quite minor. Carfax is clean.

MikeJ65 - thanks as always, I don't know why I didn't think to check the axel angles, and I'll do that next and report back in a few days.

MK19

MikeJ65
I got to the rear axle angle measurements today and what I find is a bit implausible:
LF Rear -2.4 degrees
R Rear 0 degrees
It won't raise higher that to get to 0 degrees.
This makes me wonder if the suspension bushings are gone? I was in there not long back replacing the rear strut boots and nothing looked way off base.......
Kind of tough to get a great measurement but these are close.
I note that the angle settings in the Calibration page are -2.4 to - 1.4 degrees or -1.9 degrees nominal. My gauge is rated at +/- 0.2 degrees.

Using the digital inclinometer on the deck lid I can get it level with the Rt side frt. and rear wheel opening's 1/2" higQuick Replyher than the left.

Perplexed.
MK

MikeJ65

Ignoring everything else, that half shaft angle just tells you the position of the diff vs the wheel hub, which should correspond to wheel well height. It would seem to indicate that either your diff or subframe is not square to the body.

MK19

I'll be looking that over closely next week. Will advise.

g0rsq

Once again I do not understand how if the distance from the top of the arch to the ground is equal on both sides, but the car is "leaning"! How is the OP measuring the "lean"

If I was looking at this problem I would suggest double checking the measurements.

Car is on Flat Level ground (all four corners). (Ground MUST be level at least across width of car)
Wheels are correct size, and tires inflated correctly.

Measure both distance from the arch top to the center of each wheel, and arch top to the ground. Are the two rears equal, and the two fronts equal for both measurements?

Open the boot (trunk) lid and place a sturdy (2x2 or 4x4) wooden beam across opening. Use this to place a spirit level and check level of rear (check the level is accurate by trying in one direction, then rotate level 180deg and check in other direction should be the same). Then measure the distance from the wood ends to the ground. Are these measurements equal? Is the spirit level showing the car is level?

Do the same with the wood through the rear windows sitting on the window opening.

If the height of the arches to the ground are identical (or from the ends of the wood to the ground), then the car MUST be level, unless there is significant distortion in the body.

Suspension, sub-frames, drive-shafts have absolutely nothing to do with the issue.

MK19

g0rsq, MikeJ;
Well, I tried g0's method, checking level floor, tire inflation and it confirms what my eye is seeing, rear leaning down on right side, about 0.8 degrees.
I forced it to level using Level Adjustment.....resulting in about 1" difference in left/right arch heights.
But the as I move to finish calibration by plugging in the axel angles (-7.8 degrees frt, -1.9 rear), I get a message that the "level signals are not within a valid range" and so can't complete the adjustment and lock in the levels.

The rear struts are original to the car and I'm wondering if one is faulty.........although no faults are registers. They move to the Level Adjust commands all right. No leaks etc.

I'd default to a dealer visit, but it's 4 hours away. Frustrated for sure.
MK

g0rsq

If you are observing as you describe, there is only one reason....Nothing to do with the suspension, or subframes.

Do some more measurements:-

Top of wheel arch to some fixed point on the body above the arch, such as the bottom of the window. Top of the arch to the rear corner of trunk lid. points on rear bumper to ground..etc. .You are looking for some asymmetry.of the body

If your observations are correct there must be some

I find it difficult to believe there is this level of asymmetry, but nothing else can explain your measurements.

MK19

Can't see anything amiss with the rear suspension, struts, bushings etc. The carriers are all in place and tight (likely factory tight) and the Diff too.

Measured a number of features from left to right and they're all tape measure equal.

????????

MK19

Update:
In attempting the Adaptations to level, the car, I began getting weird reactions as in sometimes the commanded corner wouldn't move at all, and other times a single tap on a function key would result consistently in more than an inch change up or down. So, I took all four corners to the lowest heights and incrementally took it back up from there, one tap ant a time and that at least took the adaptations back to normal (1/4 to 1/2 " change per tap). And, when I had it fully bottomed out, I measured the fender arch heights all around and found the right side to be about 1/2" lower that the left, both front and rear. I probably should have taken it to max height and measured it there too.