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Old 06-05-2019, 08:16 AM   #16
JGood
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Things to keep in mind:

The trailing arm has a 100% preset sweeping motion. Disregarding normal bushing deflection, the trailing arm will always move up and down along the same axis. The spring and shock are the only things that resist this movement. The spring is the only thing that will impact static ride height (the shock simply impacts how fast the spring compresses/rebounds while driving). This trailing arm motion is also not straight up and down, due to it's subframe mounting locations. As it moves up and down, the camber and toe are also impacted. What this means, is that if the ride height is different side-to-side, so will the camber and toe (assuming you have 100% straight/equivalent trailing arms). The side that is 'lower', would have more negative camber. That said, with alignment results, we can likely still get a pretty good idea of what's going on. If the camber and toe are both in the expected range for the given ride heights, you likely aren't looking at a trailing arm issue. If it's bent enough to cause that much of a ride height difference, 99.9% chance it would noticeably impact camber/toe too.

It may be helpful to take that spring spacer with you, and also get results with that installed to level the car, in addition to without (if the shop is willing).

Assuming you don't have bent trailing arms, you have checked that you have new, *equal sized* spring pads, top and bottom, on both sides?

Are you on 100% level ground? You'd be surprised the minimal amount of slope that can impact static ride height. Simple test would be to just turn the car around in that spot and re-measure.
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Old 06-05-2019, 09:06 PM   #17
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Measured it on level ground, then remeasured 180 in the same place.

All spring pads verified with a caliper to be new and matching.

One thing the shop did do was place one of the rear springs upside down and I drove on it that way for a couple days.

Here's the report without spacer. I made another appt for alignment (I have firestone lifetime alignment) tomorrow but I am not sure I can make it. Will try.

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Old 06-06-2019, 02:50 AM   #18
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Was the handbrake on when you were measuring? I find mine seems to look uneven with the hand brake on as the handbrake causes the car to squat slightly.

Mine sits slightly lower on the driver's side too, but as it's RHD it's the opposite side to you guys, with the handbrake off it's not noticeable. Maybe it's deliberate to help deal with road camber?
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Old 06-06-2019, 05:03 AM   #19
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Curiously, your rear alignment is dead even on both sides. There's a few things strange about that, especially given the ride height difference, but either way I think we can eliminate a bent trailing arm/subframe from the equation.

Regarding the handbrake, it can indeed cause the trailing arm to "hang up" and effectively raise the ride height, but only if it is applied while the car is jacked up and then lowered, or still moving, or if the car is on a hill. This is the same as if you would have it in gear, as well. If the car is on flat level ground, in neutral, and able to roll freely, applying the hand brake will do nothing at all to the car other than hold it in place.

You can swap springs/pads upside down with no issues, so disregard that.

How many miles do you have on it since you first noticed this? Are the rear trailing arm bushings poly or rubber?

You are 100% sure it was not like this prior, you measured?

Do you have the car partially disassembled, or any additional non-factory weight? (missing spare tire, smaller battery, amp/subs, etc...)

Has there been any repair work done to the chassis in the spring mounting area? The upper spring perch is just a plate of steel welded to the sheet metal... are both sides rust-free and unmodified? Same with the quarter panel lips that you are measuring too?

Disconnect a rear swaybar link and re-check, just to eliminate that. With fixed length links, there will definitely be some preload on it, which will impact ride height on both sides.
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Last edited by JGood; 06-06-2019 at 05:23 AM.
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Old 06-06-2019, 07:21 AM   #20
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To clarify, when I said to play with the spring pads, what I meant was that most BMWs in my experience don’t sit completely evenly. You will have to use asymmetrical spring pads, or coilovers if you want the ride height to be exactly the same side to side.

Note that this is not something that I would advise messing with for the sake of handling.
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Old 06-06-2019, 03:18 PM   #21
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Jgood- I wasn't able to make it to the alignment shop today but I did just get home and get the car up on jackstands in the rear to inspect all of the above-mentioned areas. I made another appointment for tomorrow 10AM to get it aligned with the spacer in.

Re: your questions I'd say about 200 miles total from when I first noticed it. It wasn't leaning like that when I first bought the car last Novemebr (stance is the first thing I check on any car, even if I don't want to buy it) that is for sure, although it was on H&R Sports with Bilstein HD's at the time - I have since swapped to IE3 and Koni Single Adjustables and I think I noticed the lean shortly after that.

RTABs are poly.

There is an amp and sub but they are centrally mounted in the trunk, with the sub poking out through the ski pass - I will remove these today just to cancel them out.

There has been no work done to the chassis, spring mounting areas, or the upper perch. Both sides are rust free and unmodified.

Fender lips have been rolled at some point in the car's past but the lean is noticeable from the rear of the car which makes me not care about the fenders until it looks even from the back. For what it's worth looking eyelevel at the fender lips I don't see anything which would make me think the lip is throwing me off.

I have disconnected the sway bar completely before but I will do it again tonight because I have done a lot of work since the last time I experimented with that.

nrubenstein - I don't know many E30 owners but the two I do personally know have cars that sit perfectly even in the back. I chase down other E30s I see on the road not to say 'hello' but to look and see if they have a lean. None of them have a lean. I don't believe the E30 lean to be a natural thing but, hey, maybe some years were even and some were not...

Here's a bunch of pics in the next post:
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Old 06-06-2019, 03:20 PM   #22
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6 of them...

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Old 06-06-2019, 03:21 PM   #23
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And another 6...

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Old 06-06-2019, 03:24 PM   #24
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Are these pics with that extra spacer back in?... because I see a spacer on the driver side

The gap between the subframe and the body looks different on the two sides.
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Old 06-06-2019, 03:26 PM   #25
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Ya, that's the spacer. Was just trying to show the unmodified upper perch in that pic.

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Old 06-06-2019, 03:29 PM   #26
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once again, is the shop again to blame for this?... or is it camera tricks?
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Old 06-06-2019, 03:30 PM   #27
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advanced photo skills here
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Old 06-06-2019, 03:36 PM   #28
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Closeups of L&R subframe bushings

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Old 06-20-2019, 12:31 PM   #29
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Hi Guys,

Sorry for the lag but work finally took its claws out of me long enough to get another alignment done with the spacer in. Here are the results:

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