88 535i suspension

Hi, I have a tough question about my 88 535i suspension.
I get a problem where I can feel the tracking slowly changing while I drive, a few hours it will be one way (maybe bad), then it will be another way
(good tracking like a new car). Often it will change from the previous day after backing out of my driveway in the morning. My mechanic can't find anything loose with the steering or suspension, the bushings are all good, and it is properly aligned. One thing I notice is if I try to alter the front alignment (one end of a tie-rod) very slightly, the tracking of the car dramatically deteriorates. I also notice if the car is not perfectly aligned, the front rotors used to pulsate considerably before I replaced the front brakes. With bang on alignment the rotors were smooth. I thought the wheel bearings were loose, but my mechanic checked them OK.
Any Ideas what is going on here?
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Your mechanic IS missing something. Having driven a 88 528e for 5 years, and reading lots, and dong my own work. I encounterd the following issues
Worn idler arm bushing. This will effect toe in/out as the rh front wheel can move back and forth in relation to the left. Steering was a bit vague. Replace idler arm.
Rear subframe bushings fell apart. Car did not track straight; constantly all over the road. Especially around turns where the rear end will have a mind all it's own.
Front upper control (thrust) arm bushings fell apart. Not real noticable except under braking, you could feel a clunk and the car nose would dive to one side or the other. If your rotors are slightly warped, this will exacerbate the problem and greater shimmy will be felt.
Worn ball joints, so I replaced the entire lower control arms with new bushings (original bushings were not bad though).
I did not have issues with the rear "dogbones", but others have.
Lots of archived info on http://bimmer.roadfly.org/bmw/forums/e28 / about the e28 suspension.
This all took place between 120-150k miles.
Cheers, Howard
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Don't forget to have your tires checked for balance and "roundness"....
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I've had it checked by several mechanics, and none could find anything. The steering wheel is tight. Trailing arm bushings, subframe bushings, and dogbones in the back have been replaced. Control arms in the front all look good. Something is moving slowly, not visible from prying and pushing with the car in the air.
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Michael Harvey wrote:

anything.
Are these guys *thoroughly familiar* with the E28?

Well, that's often the problem. They _always_ *look good*. These things have to be tested with the suspension loaded and using a prybar or a Big Damn Screwdriver and even then, you may not *see* much of anything. However, this is most likely the problem. Hit the MyE28.com Tech Forum and see what other responses you might get, but I'm betting on thrust arm bushings. If they're old, they're *probably* bad. If you're replacing them, you should *probably* spend a few extra bucks/euros/pounds and put in some more robust ones. The machined 750iL parts are closest to stock in performance while still lasting much longer than the originals.

As I mentioned above, did you try it with the car's suspension loaded? If not, it's worth a shot (Use an alignment rack.). -- C.R. Krieger (BT, DT)
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The thrust arm bushings are 750's from my mechanic who got a whole bunch of them cheap somewhere. He replaced them a few years ago, around the time I started experiencing this trouble.
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Interesting, you should find out who is the mfr of these 750i bushings that your mechanic got "cheap somewhere". OE 750i bushings are made by Boge (green insert) and OE control arms are made by lemforder. Anything else is sub-par and could mean you may need to replace them (again!)....
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I asked my mechanic. He said the thrust arm bushings are made by lemforder, not Boge. They have a green insert. If these are optimal bushings, I probably would be wasting money to replace them.
I knew a race car suspension shop (H&R Suspension) who had an unusual technique for locating moving components. They would do this: 1) Take alignment readings on the ground. 2) Raise the car off the ground, then drop it down, and roll it a bit. 3) Take alignment readings again on the ground. The difference in the two readings would show the locale of the movement. This shop used to be near me but they were too busy to fit me in. Then they moved to Florida taking all the equipment. I still haven't found anyone else that can do it. Please let me know if anyone knows of a similar kind of shop in the Toronto, Canada area. When I asked my mechanic he said this technique is not valid because the components have not had a chance to settle in after dropping the car down for the second readings. I thought rolling it a bit would settle it in.
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Is it an E28 or E34? The rear subframe to axle carrier links are often worn out and overlooked on E34's. They can make the back end wander.
Steve
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Almost sure it is E28, but not authoritative. Anyways, I know I've replaced all the rubber at the back.
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I've also replaced the dogbones. Basically everything in the back.
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