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Brake Pedal Question for e60 M5s

5.3K views 16 replies 6 participants last post by  mdyaman  
#1 · (Edited)
Been searching online, and RealOEM.com, need clarification.

Does our brake pedal have a bushing attached to it? Some sort of flex or clutch bushing attached to the pedal?

If so, does it tend to wear out over time (I have 63K miles)? I ask because I'm trying to troubleshoot a brake pedal vibration/pulsating i'm experiencing that has yet to be resolved since April '12.

my threads:
http://www.m5board.com/vbulletin/e60-m5-e61-m5-touring-discussion/215880-feedback-when-braking.html
http://www.m5board.com/vbulletin/e6...ing-discussion/213678-question-cyclical-vibration-brake-pedal-when-braking.html

And before I get asked:
I have all new rotors, new brake pads (bed ins), replaced front control arm bushings, replaced a bent rim, tires have been balanced and aligned, and brake fluid has been changed with the past 6 months. I've even swapped tires and rims with a fellow owner on here, so it isn't indicative to rims and tires. So I've ruled all those out. It isn't the DSC malfunctioning, so now i'm wondering if it's either the ABS system not functiniong properly, or, based on research online, a bushing in the brake pedal might be wearing out.


Thanks!
 
#3 ·
The UUC Brake Arm Bushings solved similar problems on my E36 M3. UUC says these work on most recent models including the E60.

Thanks Clyde!

Question, can you link a diagram or part number for the OEM ones? like from RealOem.com? Just trying to get an idea where this goes, how it installs, etc.
 
#5 ·
Thanks Clyde!
 
#9 ·
Not sure what you mean by vacuum booster. Do you mean the slave cylinder? brake pedal feels firm, as well as when braking. If there was a fluid leak I would think the pedal brake would become mushy when applying braking force. I also don't see any fluid puddles under my car.

This issue I'm having is really weird. It happens when light to moderate braking and occurs around 40 mph. That's the sweet spot for this issue. With the vibration, there is a whoooomp whoooomp whoooomp sound as the car is decelerating. Then below 30 mph it all goes away.

I don't think it's the drivetrain because when I put the car in Neutral when braking from 50 mph, the issue is still there.
 
#15 · (Edited)
It is number 5 in the picture

They usually make like road/rumble noise when they fail, either at certain speed or gets louder as the car travel faster.
Thanks for the picture. I don't hear any noise when accelerating, only when decelerating while braking. I've sent a message to my tech to see if he's looked into this.

That said, other than the symptoms I'm experiencing while driving, is there any visual cue I can look at? When I take the wheels and rotors off, is there a way to tell by looking at it, getting my hands on it?

---

EDIT. Heard back from the technician. He said wheel bearings were checked and still good.
 
#16 ·
May pretty well be a bearing. Happened to me on my M3. Front right bearing. NO noise whatsoever, but as it had a little more play that normal, each time I took a left turn quickly using a lot of grip, then the brake pedal got looooong and shaked a bit. Just because when turning, the disc would not rotate parallel to the pads, so it would push them appart, and that aditionnal brake pedal displacement was what it needed to get the pads in contact with the disc again.
 
#17 · (Edited)
May pretty well be a bearing. Happened to me on my M3. Front right bearing. NO noise whatsoever, but as it had a little more play that normal, each time I took a left turn quickly using a lot of grip, then the brake pedal got looooong and shaked a bit. Just because when turning, the disc would not rotate parallel to the pads, so it would push them apart, and that additional brake pedal displacement was what it needed to get the pads in contact with the disc again.
Thanks for your comment.

I guess the issue with my car is, after discussing with my tech, if it was a wheel bearing, the symptoms I'm having would be consistent when both accelerating and decelerating, etc. I only have it when decelerating, and noise isn't consistent either. Perhaps my wheel bearings should be examined again and given a closer look.