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Wheels shuddering, feels like ABS, but not.

3K views 24 replies 15 participants last post by  Shires 
#1 · (Edited)
Hi guys, I've got something odd going on with my 03 530i . When I am rolling though our office parking lot, I usually park in the last spot on the row and like most parking lots this one is made of concrete that has been made into large slabs. Over the years along with ground shift, some slabs are higher up than others so there are slight ledges on the lots surface, almost like mini drop offs. They feel like you're driving over a tiny bump. When I say ledge, I mean like 1 - 1.5" (inches) at most. I usually come in at a normal parking lot speed and make a left to get into the spot...not a full left turn, more of a lean to the left to get my car aligned at a 45 degree angle. If you drew a circle, I would be driving from the 6 o'clock towards the 12 o'clock and then bank left to park at 10 o'clock. As soon as I hit that one inch ledge, it feels like my ABS kicks in but if feels much more violent so I had a friend watch while I did it again and he said my entire wheel starts shaking and bouncing as if its detached somehow. All the lugs are tight, the springs and shocks look good. I never have problems going over bumps, its only on this left leaning turn that goes over a slight ledge in the road. One guy told me its my "bush's". He's british so I don't know what that means here...bushings ?

Any ideas ? I think i'm going to take a look at the wheel bearings to see if that are letting the wheel move in and out horizontally.
 
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#2 ·
Did your friend tell you which wheels were being affected???? Jack the car up on the side of the offending wheel/wheels and grab the wheel on each side. Try to shake the wheel in all directions. It should not move at all. If you have play then my guess would be that you have bad wheel bearings or bad control arms.
 
#4 ·
You can find lots of opinions on that problem in this forum, but not any real solutions. It may very be an issue with the bushings, but it happens to new and old cars both. I've never read a post that included a visual from the outside though while it was going on, so you've added to our tribal knowledge there. Thanks.
 
#7 ·
I've had two E39 530i's and both of them have done this. My current car ('03 530i sport pkg, 55k miles) does this and I took it in while it was under warranty but the dealer could find no fault from both a visual inspection as well as reading brake codes. I'm going to replace my thrust arm bushings this weekend (hopefully) with powerflex units and hopefully this will help the problem. It doesn't occur very often but it is very disconcerting when it happens and I would like to solve the mystery.
 
#12 ·
Thanks for the insight guys, I haven't been able to get any high speed enjoyment out of her for a while because I was afraid I had a bad component that could completely fail on me while driving. I didn't know this was such a widespread issue.

On the visual, the wheel that was moving was the passenger side. My friend that the wheel was moving in all directions and seemed loose as if it wasn't held down or attached to anything solid. I'll be getting the bushings checked as well as the wheel bearing because i've got 102k on there now.

I'll let you all know if any repairs are fruitful. Thanks again.
 
#13 ·
As soon as I hit that one inch ledge, it feels like my ABS kicks in but if feels much more violent so I had a friend watch while I did it again and he said my entire wheel starts shaking and bouncing as if its detached somehow..
Can you repeat the experiment with your friend? He said the wheel was bouncing... BUT:

Have him stand in front of the car and see if BOTH wheels are bouncing. I am asking, because the way all of us people who had this problem described it. We had BOTH wheels bouncing. But we were sitting in the car, without somebody watching.

That part can give much interesting information.

As to solving the problem. Read that long thread. The answer is there. I fixed that problem for my car and I didn't experience it for a few years now.

mw
 
#14 ·
I found the long thread awhile back when this happened to me for the first (and only, so far) time. In the bushing vs ABS argument, I was on the ABS side but maybe that's because the issue only seems to happen when the ABS is triggered.

But (Matwiz, this is a question for you esp.) is it that the brake cycling of the ABS resonates with the extra play from worn bushings to set up some kind of feedback cycle if it happens in just the right way? I've tried to make it happen again in safe conditions but haven't been successful.

Thing is that my 2003 530iA w/46K doesn't exhibit any other bushing symptoms. No 30-50 shuddering, no brake issues, nothing. Couldn't be smoother and more perfect feeling on the highway at any speed up to the buck 20 i've had it to so far (had the car for only a couple of months). So that's why I was skeptical of the bushing issue.

But as the car is still under CPO, I'll see if I can't get the dealer to do something about it or at least inspect them.
 
#15 ·
.... In the bushing vs ABS argument, I was on the ABS side but maybe that's because the issue only seems to happen when the ABS is triggered.

But (Matwiz, this is a question for you esp.) is it that the brake cycling of the ABS resonates with the extra play from worn bushings to set up some kind of feedback cycle if it happens in just the right way? I've tried to make it happen again in safe conditions but haven't been successful.
...
In my mind it was not the Bushing Vs. ABS per se. (or only). It is my experience that the front shock absorbers (struts) were the source of the problem.

Mine were completely gone. Meaning, ZERO resistance was left in them.

The thing about the 'harmonic resonance' is that it can be caused by any of a few factors that are involve with a movement of the wheel up and down, and they all work together. The problem is that the movement is too 'free', and therefore can resonate. If you introduce a resistance (dampening) into the movement, the cycle of the resonance will be broken, and the problem is solved.

My problem with the bushing being the problem is, that what it means is that after the bushing are replaced, the suspension is stiffer, and therefore the problem is "solved". But only temporarily, because as our bushings get worn out every 30-40k miles, that means that the problem will come back. And you still ride on weak struts.

However I think that replacing the bushing is only masking the real problem: that the shocks are gone.

Since I replaced my shocks (struts), actually the whole suspension to Koni/Dinan, the problem has gone forever. I since replaced 3 sets of bushings, and the bushings had no affect on the bouncing whatsoever.

mw
 
#16 ·
But...is it that the brake cycling of the ABS resonates with the extra play from [...insert part here...] to set up some kind of feedback cycle if it happens in just the right way?
Exactly!

mw
 
#17 ·
THIS IS AN OLD THREAD!

I'm cross referencing this old thread to a new thread today positing to use MatWiz' ABS/shock cross-interaction theory as a test for bad front shocks.

However, in the spirit of this old thread, please note that if it were the bushings, then the violent shudder would not go away merely by disconnecting the ABS control module harness connector, as it did with my violent shudder.

So, for anyone else trying to differentiate the reason for their violent shudder (and yes, we know what ABS pulsation feels like - and this isn't it), simply pull the ABS fuse or disconnect the ABS control module harness and you'll know right away whether the violent shudder is due to shocks or bushings (on your very next braked bump).

 
#21 ·
My thrust arms are way toast so I'm guessing that's my problem
I don't understand what "thrust arms" and related "bushings" do ... so may I ask (what might be a dumb) question?

Keep in mind the "symptom" totally disappears when the ABS is disabled.

QUESTION:
Since the symptom totally goes away with the ABS temporarily disabled, does that repeatable reliable fact point us more to thrust arm bushings or more to bad shocks as the culprit?
 
#19 ·
Mine were the thrust arm bushings.

I have a little 3/4 inch "step" where the threshold of the garage floor meets the driveway. If I went into my garage a bit too fast, the ABS went crazy. The first time this happened, it scared the sheeez:yikes: out of me since I thought I was going into the back wall of my garage.

The shuddering would also happen when braking over broken road surfaces (the road near my house needs resurfacing, lots of cracked and broken asphalt.)

It's never ever happened again, neither in my garage nor the broken asphalt road, after I replaced the thrust arm bushings.
 
#23 ·
I vote for ABS and ABS only: a weird anomaly I've experienced three times in three years. Go over a little bump at low speed and the ABS kicks in and violently pulsates the brakes. Before you pull out your hair and front suspension, understand ABS is designed to pulsate your brakes and bring your car to a stop in a rolling skid fashion: roll, skid, roll, skid, roll, skid, etc. Why the ABS gets confused sometimes at low speeds, I have no idea, but unless its happening regularly, I say don't worry about it.
 
#24 · (Edited)
I seem to have had two different problems corrected by new thrust arm bushings:
1) From around 30k miles or so, until 70k miles, I had a mild, rotational knocking noise when making hard right hand turns at 50 mph and faster. Suspension was inspected at 30k and said all was well, at 70k the inspection said the thrust arm bushings are toast and new ones cured the problem. No other symptoms.

2) More recently (now at 145k miles) I have had a very mild pulsing through the steering wheel when braking from freeway speeds...almost like warped rotors or deposition of brake pad material on the rotors. Well I just had my control arms and thrust arms replaced (Lemforder with Meyle HD thrust arm bushings) and now the pulsing or mild shudder is completely gone. The thrust arm bushings only had cracks on the drivers side, and there were only two, very small ones...not very significant at all, and no sign of fluid leaking. Though they had 75k miles on them, I was surprised it made that big a difference since they visually looked fine.

I also had my tires replaced, so it is possible the tires had something to do with it as well.
 
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