WTF is Wrong (Front End Vibration)

Alright, I've already had one suggestion for what the issue is, but for the sake of getting unbiased answers, I will not repeat that suggestion (and stay away from the bimmerforums you cheaters).

Car in question: 1996 BMW 318ti, Koni SAs, 460lb front springs, Eibach 27mm front sway on full stiff.

Issue:

I have a vibration through the steering wheel whenever turning hard to the right. Speed doesn't matter, angle of steering doesn't matter, camber doesn't matter (does it at -2 and -3.5). Tires also don't seem to be the issue (it does it on the 225/16s and the 205/15s) The only time it happens is when turning right.*

I noticed the car doing this on the street last week when I was exiting a round-about. At first I thought it was a noise, and I thought it was a "whoom whoom whoom", but as time has gone on, I've learned that it is neither (in other words, not a noise, and not "cyclical").

At the autocross today, it was there. I marked the inside of my wheel wells to look for rubbing, and I haven't found any. My fiance also ran the car today, and I worked the center of the skid pad. There is no abnormal noise.

*After the race today, I did feel the vibration when backing up into a parking spot, but only if the spot was uphill (as in, the car was moving backwards, uphill).

Control arm busings and ball joints were replaced within the last 20K miles. I just did the tie-rod ends yesterday. Sway bar endlink bushings are shot, but I didn't have time to replace them before today. The front wheels feel firmly attached to the hub and there is no perceivable play. Lugs are torqued correctly.

What are your thoughts? Ideas? What else to check?

wheel bearing?

I assume the car has power steering, right? Reason I ask, what you describe sounds very much like a hose vibrating. Town and Country vans do that a lot, some much worse than others and it's the return hose vibrating. Check the hoses, look for a missing rubber pipe clamp bushing etc.

Mad Machine, you win the prize for naming what others have thought. I don't want to rule it out, but it just doesn't "seem" like a wheel bearing to me. At least, it's not failing like I've been told to expect wheel bearings to fail.

Jensen - that's a really interesting idea. I'll have to poke around.

the going into reverse is what gets me.. when i redid the suspension on my ti.. the bushings literally fell apart in my hands.

Have you had your wife drive the car slowly while you watch the wheels in question? Also check the rear suspension, I still need need to redo my subframe bushings and the rear CAN drive the front when things get loose back there

when the p/s pump went on my old ranger and it went low on fluid, the wheel started vibrating whenever i'd turn the wheel and the pump i guess didnt have enough fluid to assist the steering. when it did run dry, the vibes stopped and it just started whining and not helping much

My rear subframe bushings need to be replaced too.... that's an interesting idea. When you say "the going into reverse is what gets me..." do you mean, that makes you think wheel bearing, or that makes you think something else...

EDIT - I just tried to replicate the "backing up" issue and I could not. I had just as steep of a hill to try. The only difference was the front camber was back to the setting (-2) and the weight of tools, etc, was in the back of the car.

Interesting idea Strizzo, but it only happens when turning right. There are absolutely no symptoms when turning left.

My E30 would make a GROOOOOOoooaaaaannnnn whenever turning left when I first got it and it was the pass wheel bearing (and I couldnt discern play in it) If the bearings arent too expensive just start there.

I would have to hear the sound to better guess if its that though.

seeing as it happens only one direction i personally am gonna rule out the pump and p/s cause that should affect it both directions if its a hose or fluid. unless ts a kinked crossover hose, loose column mount or rack mount. In any case ive seen really bad wheel bearings do this but they have to be shot almost to the point of removing themselves from the car and it would make some noise. possibly a binding axle thats not really noisy but transferring cv movement up into the wheel. But you should check the rear suspension as well (bushings and such) alignment issues between front and rear can cause this type of binding vibration, ive had cars toed in or out to much and when you turn the wheel you get a binding or rubbingthat trasfers into the column. Does it happen while braking or accelerating? Did the car always have this problem?

Apexcarver wrote: My E30 would make a GROOOOOOoooaaaaannnnn whenever turning left when I first got it and it was the pass wheel bearing (and I couldnt discern play in it) If the bearings arent too expensive just start there. I would have to hear the sound to better guess if its that though.

That's the thing. No sound. Only vibration.

is the frequency dependant on road speed or not?

curtis wrote: seeing as it happens only one direction i personally am gonna rule out the pump and p/s cause that should affect it both directions if its a hose or fluid. unless ts a kinked crossover hose, loose column mount or rack mount. In any case ive seen really bad wheel bearings do this but they have to be shot almost to the point of removing themselves from the car and it would make some noise. possibly a binding axle thats not really noisy but transferring cv movement up into the wheel. But you should check the rear suspension as well (bushings and such) alignment issues between front and rear can cause this type of binding vibration, ive had cars toed in or out to much and when you turn the wheel you get a binding or rubbingthat trasfers into the column. Does it happen while braking or accelerating? Did the car always have this problem?

I can't say for certain if it's under braking, but it is under accelerating. I will test to see if it's happening under braking.

No CV's up front, RWD.

Alignment is 0 toe -2 camber or -3.4 camber and lots o toe out in the race setting. Rear is about -1* rear camber and a little toe in. The vibration is a recent happening and the alignment predates the symptoms. Rear subframe bushings and diff bushing are not in good shape and are due for a replacement, but that has been that way for a little while (not that they haven't gotten worse).

The car has recently developed a slight "twitch" in the steering wheel when you hit the brakes quickly. Easy on the brakes and nothing weird, but a quick hit to the brakes causes a few degrees turn in the wheel. Nothing out of control, but noticeable. Best I can tell, this brake issue came around about the same time as the other issue, but I can't be certain. Plenty of meat left on the pads.

Wheel bearing isn't cheap, and combined with the lack of noise is what makes me hesitant to dive in on that.

Apexcarver wrote: is the frequency dependant on road speed or not?

No, vibration is a consistent frequency over. Happens at 20 or 50, all at the same rate.

Front End Vibrations are like Cancer, anything and everything causes them, they are hard to diagnose and harder to get rid of. I have one on every car I own and diagnose them as often as I eat or sleep. Good luck.

can you tell if it is an up and down vibration (bent rim feel) or a wobbly type vibration (bearing bad vibration)?

Not a bent rim. It's just a vibration. Like holding on to the device that derives it's name from that action... so I've been told.

It almost feels like a tire push, but it's not.

Gimp wrote: The car has recently developed a slight "twitch" in the steering wheel when you hit the brakes quickly. Easy on the brakes and nothing weird, but a quick hit to the brakes causes a few degrees turn in the wheel.

Worn control arm bushings are often at fault for this, I know you just replaced them 20k ago but they're worth checking. I've had new one's develop mushiness after less miles. The bushings for the e30 are stiffer than the e36 units, going to the m3 offset bushings would be even better.

The noise is weird though, wheel bearing noise always changes pitch with speed so that's out. I'm going to guess it's some worn front suspension component ( inner tie rod end?) causing an oscillation which you're feeling. Jack that puppy up and go to town with a pry bar, something will surface.

I would definatly check the "lollipops" if you are getting changes under braking, then those bushings are allowing the front end to shift.

I put powerflex in mine (non offset) and I could not be happier

ansonivan wrote:

Gimp wrote: The car has recently developed a slight "twitch" in the steering wheel when you hit the brakes quickly. Easy on the brakes and nothing weird, but a quick hit to the brakes causes a few degrees turn in the wheel.

Worn control arm bushings are often at fault for this, I know you just replaced them 20k ago but they're worth checking. I've had new one's develop mushiness after less miles. The bushings for the e30 are stiffer than the e36 units, going to the m3 offset bushings would be even better. The noise is weird though, wheel bearing noise always changes pitch with speed so that's out. I'm going to guess it's some worn front suspension component ( inner tie rod end?) causing an oscillation which you're feeling. Jack that puppy up and go to town with a pry bar, something will surface.

It's (obviously) driving me a little nuts too. I just replaced the entire tie-rod assemblies from the rack out with no change, so it's not them.

I have the sway bar endlinks new, ready to go in, so I'll get on that next. The urethane bushings that connect the sway bar to the chassis were just greased and are in good shape. I did shave a little off the top of the bushings to reduce bind... I wonder if the bad endlinks (much, much worse on drivers side) are causing the bar to shift... zip ties will show me!

The lolipops are in really good shape. I had suspected them originally, and they looked good so I moved on. Maybe some modeling clay in the voids in the bushings and a quick drive will show me more.

I used the pry bar on the bail joints and didn't notice an issue, but I'll poke around some more.

well, it does seem like something is causing some toe/caster problems

I had this same EXACT issue on my EGT, down to a T.

It was the right side control arm bushing.

That's my vote.

93celicaGT2 wrote: I had this same EXACT issue on my EGT, down to a T. It was the right side control arm bushing. That's my vote.

Right side... as in passenger? To be honest, I looked at the driver's side control arm bushing, but I can't say that I looked at the drivers'. Stupid assumption on my part. Since the problem was when turning right, and most of the time when turning right BMWs can't be bothered to put the inside wheel on the ground, I wasn't considering that side of the car to be a factor.

it does make sense actually. The outside wheel will be fully loaded down and not be moving no matter how shot the bushing is.. but the inside is all but floating free and if there is any looseness in the bushing, will occilate as the bushing allows it to move about

mad_machine wrote: it does make sense actually. The outside wheel will be fully loaded down and not be moving no matter how shot the bushing is.. but the inside is all but floating free and if there is any looseness in the bushing, will occilate as the bushing allows it to move about

That is a really interesting idea, and I will give it a look. I will say that during the race yesterday, I was on the inside of the skid pad as my fiance went around it (clockwise). I can't be 100% certain if she was pushing it hard enough to create the issue, but I did not see any strange movement from the inside wheel.

Someone on the bimmerforums has an upgraded set of control arm bushings and may be in the same town I work in, so that could be a plus.

Gimp wrote:

93celicaGT2 wrote: I had this same EXACT issue on my EGT, down to a T. It was the right side control arm bushing. That's my vote.

Right side... as in passenger? To be honest, I looked at the driver's side control arm bushing, but I can't say that I looked at the drivers'. Stupid assumption on my part. Since the problem was when turning right, and most of the time when turning right BMWs can't be bothered to put the inside wheel on the ground, I wasn't considering that side of the car to be a factor.

Yup. It was making the noise from the right, and it was the right side that was messed up.