Steering wheel starts to vibrate at 55 mph vibration goes away at 65 mph or if i maintain 55 to 65 mph while applying pressure to the brake pedal vibration stops. also when drive over a curb, (e.g.backing out of driveway or entering driveway with a normal sidewalk and gutter) there is a sharp thud in passenger side front tire. tires are not out of balance, alignment is fine,

tires out of balance or a bad wheel bearing

after you have changed the control arms on the front suspension did you send it for steering geometry ( tracking )? If not,then the problem you have is your front steering alignment is out and that's why.

you have wheel bearings failing
the random abs light is the rotor for the sensor touching the sensor head because the wheels are loose on the shaft

I would look at the half shafts or cv axles.

bent tyre or dish rim, check tyres and rims and speed balance would help.

Torque convertor shutter? Maintain the speed that it does this, and with your left foot, apply a small amount of pressure to the brake pedal. Not enough to slow vehicle, but enough to disengage the lock up convertor. If it goes away, try servicing the fluid with new 7176. if that doesnt do it, replace the convertor.

Hi:
Since your BMW 540 series is a rear wheel drive car, a common cause of that sort of vibration is often the U joints on your drive shaft. The vibration often only shows up and certain speeds.

It isn't a particularly expensive repair, but is something to have checked out!

if it were the rotors it only happens when braking take in have them turn rotors see what happens good luck

Vibrations while driving like you are describing can come from tires that have defects (internally broken belts) (wheel weights that have fallen off) or a bent rim (perhaps from another driver [not you :-) ] hitting a curb) Are the tires worn? Have they been balanced and rotated regularly? You report no vibration in the steering wheel.
Vibrations during braking can be warped rotors or discs (but this doesn't sound like your problem since these kind are usually felt in the steering wheel during braking).
If and only if you feel like you can do this safely,
you can try getting the car up to 55, placing the car in neutral, then switching the "engine off" but leave the "key on" (be warned the power steering will go out but the vehicle can still be steered though the steering wheel will be much stiffer) if you try this (do it perhaps in a vacant parking lot or on an empty road) and the vibration goes away with the engine off but while the vehicle is still moving, then the vibration is engine or transmission related. If this is the case you might hope for maybe a bad engine mount. Bad engine mounts can be diagnosed with the vehicle stopped as well. However, if the vibration remains with the van moving forward but with the engine off, the vibration is likely a problem with the tires or suspension. Try to provide some more info.
If you don't feel comfortable trying the above suggestion, please take the vehicle in to an ASE certified suspension and steering professional for further diagnosis.

Finally, I had a similar situation happen to me today. I was riding with a friend in their van and the vehicle started vibrating more and more around 55 mph. We stopped and carefully checked the front tires (including the lug nuts for tightness) but
found a tire defect. (it had several broken steel belts that caused a bulge in the tire and thus the vibration) We changed the tire and the vibration was gone. Good luck to you.

Check your drive shaft u-joints..Number one cause.Have a great night!!!

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