dentar

Hi everybody!

So I have problem with braking, the issue is that when i lightly touch brakepedal i will feel vibrations (at a very fast rate, it goes faster, the faster the mph)
If i would brake hard, like step on the pedal, i wont feel the vibrations..

Classic warped rotor you may guess? misaligned? wheels?
seems not. Here's the list of what i've done with the car during a 2 year time.

Nothing is anything cheap aftermarket stuff. OEM or better.
New brake discs front + back.
New brakepads front + back
swaybar bushings twice front
all 4 control arms front (replaced as whole, ball joint + bushing)
the small link arm(?) both sides front, the one that's mounted vertical
wheel bearings front
balanced wheels twice, I also have 2 sets of wheels and problem occur with both
aligned car twice, havn't done any repair / replacement after last alignment, car goes perfectly straight etc.

I do use spacers in front on one set of the wheels (for looks) and the vibration gets abit worse then,
still the vibration persists even without spacers on the same set of wheels.

Car have 160 000km on the clock, very well taken care of.

Any suggestions?

Plutoe

Whatabout the rotors

dentar

English isn't my native language, but isn't rotors = brake discs? they are replaced all around anyway. as well as wheel hub front.

Erik C32

I had a similar issue after I replaced my brakes and had my wheels powder coated. The problem was caused by the layer of powder coating on the rims. The rims were not 100% pressing against the discs, which caused vibrations under light braking but disappeared when braking hard. After I removed the layer of powder coating on the inside of the “centering hole” (or whatever it is called in English), my problems were almost gone. I had to change discs again and then everything was ok again.

Can you try different rims and check if the thread of all the bolts are OK?

godpossessed

I think I have isolated this issue on my 2002 C32. It turns out that it was the torque struts (control arms). At 166,000 mile the rubber bushings have deteriorated and when I brake it takes out the slack in the bushing. At "parking lot" speed I get a thump as the play in the suspension is taken up when I touch the brakes.

At driving speeds, light braking induces an oscillating taking up the slack (and the springing back) in the worn torque struts and produces a feel in the brake pedal like a warped brake rotor. A firm press on the brake pedal forces the slack in the suspension to its limits and no oscillation occurs. I am currently having the torque struts replaced and will try to report back after.

Edit: I read over where you replaced your control arms. Sorry I missed that

dentar

Late reply, but i finally decided to tackle this and really find out whats wrong, heres what i came up with:

Purchased a dial gauge to rule out anything wrong with rotors etc.

Wheel bearings both sides front have play, turns out when i installed them i didnt seat them properly (did this by hand/feel, no bueno)
Adjusted wheel bearings to spec (0.02mm axial play) still have a cluncking noice vertical movement from bearings so they will be replaced, again.

Rotor driver side passes the test! 0.02mm play
mounted spacer ontop of rotor, snug down with wheel bolts, 0.4mm play!! 20 times out of spec (these are hubcentric spacers)
wirebrushed everything to perfection, same result.

passenger side rotor 0.02mm play, passes test! alto i find cracks all over the venholes in the rotor, these are about 1½ years old.
brake pad on the same side the cracks are is way more worn down than the rest of the pads, so a repair kit is in order.
spacer same thing here 0.4mm play, 20 times out of spec

Soo.. 2x new wheel bearings, 2x new rotors and pads & 2x repairkit for calipers. Not my day today
I need spacers for the wheels to clear calipers, might consider getting rid of them..

Oh, and i havn't even checked rear yet