Pulsating Brakes?

[ClutchJones]

Recently I have started to notice a slight pulsing as I am applying the brakes. It's more pronounced at slower speeds, as if I can feel a (possibly warped?) rotor or something off balance.
I took it to the tire shop and had the tires rotated and balanced, but that didn't stop the problem. It's been about a year since my last brake job.
I also had to replace the ball joint at that time on the passenger side. Is it possible that the ball joint is going bad on the driver's side now and causing the problem? I'm hypersensitive about that kind of thing and ocassionally think I can feel a slight tap or knock as I'm turning into a parking lot...
Any ideas from my expert buddies at 318ti.org?

[JPerfect]

is it in both directions, the turn?

Could be control arms or tie rods... I had a similar problem before I got all that replaced.

[Adog2107]

sounds like its time to change your thrust arm bushings

[ClutchJones]

The slight tap I mentioned only happens on a rare occasion and is extremely subtle. It's not really even audible and I only feel a slight tap around the floorbard on the driver's side, and very slightly on the steering wheel. It only happens when I turn left and up the slight incline into a parking lot or driveway.
It may or may not be related to the pulsating when braking, but the pulsating happens all the time and the tap is rare. As I mentioned, it is more pronounced when I am going 5-10 mph or less and gently applying the brakes.
It almost reminds me of when I was a kid and didn't put my bicycle wheel back on straight and it would rub the frame when a certain part of the wheel came around...
I don't hear any rubbing, though.

[3DGE]

I got that too, and my brakes have a squeek, I am going to just buy the whole lot and startout fresh...giving i just got my ti.

[cali-ti]

pulsating could be a couple things. there may be some brake material built up on the rotor, i would try some hard brakes from say 60mph on an empty road to see if you can burn it off as a first try. when you come to a hard stop, you want to release the brakes if at all possible so you don't get pad transfer to the rotors or at least release and roll a bit, re-apply, release and roll, etc to minimize it. if that doesn't fix it, i would guess the rotors are warped. if the pulsing is only slight, it's possible to get them turned. you may want to think about the upgrade to e36 32x vented front brakes (you'll need the calipers, carriers, rotors, pads) as those will be more resistant to warping.

EDIT: do you feel anything in your steering wheel while braking or is it all in the brake pedal?

[davep-uk]

same problem, but no feeling through pedal, its all through the wheel.

[ClutchJones]

pulsating could be a couple things. there may be some brake material built up on the rotor, i would try some hard brakes from say 60mph on an empty road to see if you can burn it off as a first try. when you come to a hard stop, you want to release the brakes if at all possible so you don't get pad transfer to the rotors or at least release and roll a bit, re-apply, release and roll, etc to minimize it. if that doesn't fix it, i would guess the rotors are warped. if the pulsing is only slight, it's possible to get them turned. you may want to think about the upgrade to e36 32x vented front brakes (you'll need the calipers, carriers, rotors, pads) as those will be more resistant to warping.

EDIT: do you feel anything in your steering wheel while braking or is it all in the brake pedal?
The pulsating is the entire car, lurching and slowing at a regular interval, only when braking.

[cali-ti]

same problem, but no feeling through pedal, its all through the wheel.
i would guess yours is not brake related, but possibly the control arm bushings, ball joints or tie rods. does it tend to have trackings issues too, especially on grooved roads?

[cali-ti]

The pulsating is the entire car, lurching and slowing at a regular interval, only when braking.
do you feel the pulsing in the brake pedal itself (up and down) or not? that's usually pretty indicative of warped rotors or pad transfer to the rotors.

[ClutchJones]

It's almost like I am pumping the brakes as I slow. It involves the whole car evenly. There is no pull to either side as the car decelerates.
I'm not getting the left and right jiggle on the steering wheel, like I might get if the tires were badly out of balance.

[cali-ti]

yep, sounds like warped rotors or pad transfer.

[ClutchJones]

Thanks, Stabby
I was thinking of changing rotors and pads all the way around, anyway. I'm all stock now and still owe the bank a few payments, so I don't want to do any mods at the moment. Although I do plan on keeping the car a long time. I bought new rotors last year. Should I try to turn them first? What's a good source for the materials?

[cali-ti]

if they're that new, i would certainly think there'd be enough there for them to be able to turn them. what "materials" are you referring to?

[davep-uk]

i would guess yours is not brake related, but possibly the control arm bushings, ball joints or tie rods. does it tend to have trackings issues too, especially on grooved roads?


sounds like you've driven my car! it having an oil service tommorow, i'll get them to check tose bits too. its been happening for a while but i'm just a lazy sod!

cheers Stabby.

[ClutchJones]

if they're that new, i would certainly think there'd be enough there for them to be able to turn them. what "materials" are you referring to?
New pads, etc. I saw the stuff at bavauto, but the rotors look pretty expensive and I'm hoping not to have to replace them.

[cali-ti]

the question is, will you really need new pads or rotors? rotors i'd go OEM, just get them from a dealer that gives a good discount (eg: crevierbmw.com). pads are more open and personal choice (there have been a ton of threads on that subject). if yours aren't close to being worn down, i would think you'd be able to reuse them.