Car shaking while driving at highway speeds

[mdimillo]

I was driving my car on the highway today and I noticed a very very consistent shaking. The entire interior, shift lever etc. was shaking with the car and I was wondering what it could be.
This continued until I reached my destination. I had even put the car in neutral and nothing changed.

This just has me concerned if it's a safety thing or something, I don't want to risk anything. Anyone experience a similar issue? Is it the CSB or something?

[FLarimer]

Shaking in the front end? Like feeling it in the steering wheel?

Had something like this happen in my E34 M5 - turned out one of the front calipers was seized and was the cause. Further investigation revealed the brake system had not been serviced by the PO for many, many years and the system had contaminated fluid (water in the system) causing corrosion on the pistons, preventing them from moving (retracting) freely and resulting in seized pistons. Would happen driving on the interstate and the whole front of the car would shake like madness. Moments later all would be fine...made me crazy until I talked to a mechanic friend who immediately said "seized caliper - check your front brakes".

PSA here - we forget to routinely change out the brake fluid. We change oil, change brake pads but seem to forget to flush the system every other year. Imports (i.e. German cars in particular) seem to be prone to collecting moisture in the brake systems over time and that causes corrosion in the calipers - resulting in problems as you are describing - as well as unexpected brake master cylinder failures (BT, DT) and trust me, first you say "it", then you do "it" - not a fun experience to have the brake pedal collapse to the floor just when you are exiting the interstate and the light at the end of the ramp is RED....

Moral of this story - flush your brake systems annually - it's not that hard and not that expensive to do. The sheetmetal you save may just be mine....

[K Fox]

OP - do a forum search for '55 mph shimmy' - that will answer your questions and guide you towards a fix. Brakes are a possibility, but it's much more likely that you have some worn suspension/steering parts. Most likely thrust arm bushings.

Fox

[shogun]

I have some more -also to me new- experience now after working 4 days on an Alpina B12 E32 750iL. The shop gave up on that problem and the owner found me+buddies via the internet and drove more 100 miles to my place and left the car there for a week, 60-150 kmh no problem.
That was a shaking I have never experienced, but ONLY under certain conditions, normally it ran relatively smooth.
It was not speed related, there were -now we know- certain criteria to be present at the same time, critical unbalances/vibrations of several parts at the same time at their peak and road roughness. Then the car started shaking like hell, undrivable. This shaking even was so strong that it destroyed the metal bsuhes inside the thrust arms, they were bended.

So we started to eliminate step by step
swopped Alpina wheels and tires from another B12, no change
swopped front shocks and shock mounts from another parts 750 into the B12, no change
replaced center bearing of driveshaft, slight improvement
Installed new front brakes and brake pads, cleaned the surfaces carefully and checked the front brakes. New brake fluid and brake bleeding, checked the brake calipers etc if stuck or damaged.
Checked rear handbrakes/parking brakes if they get stuck sometimes, as an experienced retired former Meister from a BMW shop who knows these cars well told me, that it could be that the springs on the parking brakes could be too weak and if too tight adjusted the linings could start touching/vibrating on the drums, causing vibrations. So we losened the parking brake completely and checked the bowden cable.
Replaced upper arms/thrust arms, lower arms, stabilizers, dogbones, beer cans, again some improvement. So we made a test drive on the Highway, 30 miles fine, then suddenly at only 60kmh the shaking came back. Back to my place and found the damages on the bushes of upper thrust arms which were just installed new again. Replaced the bushes again to new ones which we pressed in.
Then we replaced: engine mounts, trans mounts, idler arm, pitman arm, center tie rod, tie rods, retightend steering box, BINGO, problem solved. Runs as smooth as silk now.
I do not know where it started, but the worst condition were the balls at the center tie rod, one had so much 'play', I could pull it out by 1-2 mms. Maybe that was the beginning of all the trouble and then step by step all other steering and sus parts got damaged, starting by one defective component. And when all of these components were at their peak vibrations and the road surface "worked as ignitor", the big shaking started.
Before I was always of the opinion to change only upper and lower arms, which indeed in most of the cases are the problem, but here I learned that ALL components must be in perfect condition and if one part is bad, it even can damage quickly new installed parts.

[MacLoGoS]

Have your wheels rebalanced and if you are running aftermarket or rims from a different model bmw (for example e39 rims) make sure that you have hub ring adaptors. Old tires can also cause shaking so be sure they are also in good shape.

- - - Updated - - -

Front wheel bearing failure can also cause shimmy or shaking. I also had mine fail on me causing braking issues.

[SW530]

Unfortunately MANY things can cause what you describe and all anywhere here can do is guess by suggesting fixes that worked for them in the past, but with so many possible causes not very productive.

This is one of those times a Sears Auto Center might prove useful. They do free inspections and estimates.. they might not be NASCAR grade mechanics but their physical inspection is probably going to be more accurate than a guess over the internet.

[teutonik]

Agreed. It wasn't until I physically got under the car with a pry bar that I could diagnose my control arm problems. So if there's a respectable garage offering free inspections for basic stuff, do it and you don't have to get dirty, but as others have said, it can be a lot of things, even a combination of a lot of things.

[staystackin]

A little bit more specific information can help us help you, also.

Did the shake start or stop at certain speeds? Was it consistent and also present during regular (non highway) driving?