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-   -   High Speed Vibration when Brakes (http://www.bimmerfest.com/forums/showthread.php?t=626710)

16valex 06-12-2012 11:59 AM

High Speed Vibration when Brakes
 
Damn, I can't believe I start this thread, but here we go.

At high speed above 60MPH, if I hit the brake hard the whole car would shake.
Jacked the car up and all is tight. NO play in wheel bearings neither.
All front suspension components has been replaced within the last 10K miles.
I thought I may have a sticky caliper but when I check both wheels are spinning freely.

I'm going to bleed the brakes and see how this go, but first I will try the bedding procedure and see if this help.

I don't like the feeling at all, during high speed, very unsafe.

dvsgene 06-12-2012 12:04 PM

Hey Alex, I presume you used Lemforder parts during replacement?

In either case, I also presume you preloaded before tightening down thrust arm bolt?

I'm sure you know how and what to check and this seems more like a "venting/ranting" post.

Perhaps your surpercharger has added too much weight to the front making it less than ideal 50/50 distribution. Time to take that thing out!


Thanks for sharing and good luck!

cn90 06-12-2012 12:15 PM

Resurface the rotors.

16valex 06-12-2012 12:16 PM

Ha ha! Gene you're funnier than I thought, just so you know even with the added S/C weight mine is still lighter than yours . :)

Yes, all parts were Loemforder and pre-load during the arms installation.
Thanks for chime in though.

16valex 06-12-2012 12:18 PM

Quote:

Originally Posted by cn90 (Post 6891160)
Resurface the rotors.

Yeah! I might have warped rotors, but I don't think I would re-surface them.

dvsgene 06-12-2012 12:29 PM

Quote:

Originally Posted by 16valex (Post 6891164)
Ha ha! Gene you're funnier than I thought, just so you know even with the added S/C weight mine is still lighter than yours . :)

It may be lighter but is it faster? :dunno:

I have another solution, Keith is very good at solving vibration issues. Give him a call so you can replace everything again and again and again.:rofl:

Jason5driver 06-12-2012 12:41 PM

Pad deposits on the rotors...
Try re-bedding them, BEFORE re-surfacing the rotors...

pleiades 06-12-2012 12:57 PM

Find a clear open place (large parking lot after business hours) and try braking firmly in reverse a few times.... (Yeah.... I just make this sh*t up....) :)

16valex 06-12-2012 01:23 PM

Quote:

Originally Posted by pleiades (Post 6891256)
Find a clear open place (large parking lot after business hours) and try braking firmly in reverse a few times.... (Yeah.... I just make this sh*t up....) :)

It's cool and genuine idea, I like!

16valex 06-12-2012 01:27 PM

Quote:

It may be lighter but is it faster? :dunno:
Wanna know! It's gonna cost ya!

Quote:

I have another solution, Keith is very good at solving vibration issues. Give him a call so you can replace everything again and again and again.:rofl:
So true, we all learned from his mistake!:eeps:

16valex 06-12-2012 01:30 PM

Quote:

Originally Posted by Jason5driver (Post 6891224)
Pad deposits on the rotors...
Try re-bedding them, BEFORE re-surfacing the rotors...

I will try re-bedding them but definitely not re-surface them, it's not worth the time and labor IMO.

Fudman 06-12-2012 02:23 PM

Quote:

Originally Posted by Jason5driver (Post 6891224)
Pad deposits on the rotors...
Try re-bedding them, BEFORE re-surfacing the rotors...

+1, always do the easy and cheap steps first!

cn90 06-12-2012 02:49 PM

- Re-bedding might have been OK when installing new pads.
If the pads are old and worn in, chances are: warped rotors.

- Even brand-new rotors may be a bit out of specs.
When you re-surface the rotors, you know it will true and straight.

- I go to my local OReilly autoparts often and they re-surface the rotors free for me.
Otherwise $10/rotor resurfacing.

Trust me, been there done that, resurface the rotors, the problem will go away.

16valex 06-12-2012 07:35 PM

I had done the re-surface once before on the same car but that didn't last long maybe about 2K miles or less.

I'm going to give it a good check tomorrow.

16valex 06-13-2012 07:08 AM

Update
 
This morning.
-Checked strut mounts nuts. Nice and tight.
-Checked front rotors. They're beautiful looking, a uniformed gray color across, no visible hot spots or glazing of any kinks.
-Checked calipers bracket housing. Nice and tight.
-Checked calipers hanger rods. Nice and tight.

Went out and performed the zeckhausen brake bedding procedure.
The vibration has cut down drastically, not as sensitive as before when as soon as I touch the brake pedal the vibration was instantly vs now it would take about an inch down before the vibration kicks in but at a 25% scale of violence.

Now I'm not sure if the bedding procedure helped flatten the high spots (which I didn't see any to begin with or felt the pulsation in the pedal) OR perhaps in the process of bedding it helped remove the air out of the brake system.

I'm more leaning toward air in the system perhaps in the ABS module which is very hard to get rid off unless you have a tool to activate the ABS module while pressure bleed the brakes.

I will try to pressure bleed the brake and see if I can get rid of the last 25% remain vibration.

What do you guys think?

johnstern 06-13-2012 07:30 AM

Which car is this: the 528 or the 530? Is your brake pedal a little squishy?

Jason5driver 06-13-2012 07:38 AM

Quote:

Originally Posted by 16valex (Post 6892659)
This morning.
-Checked strut mounts nuts. Nice and tight.
-Checked front rotors. They're beautiful looking, a uniformed gray color across, no visible hot spots or glazing of any kinks.
-Checked calipers bracket housing. Nice and tight.
-Checked calipers hanger rods. Nice and tight.

Went out and performed the zeckhausen brake bedding procedure.
The vibration has cut down drastically, not as sensitive as before when as soon as I touch the brake pedal the vibration was instantly vs now it would take about an inch down before the vibration kicks in but at a 25% scale of violence.

Now I'm not sure if the bedding procedure helped flatten the high spots (which I didn't see any to begin with or felt the pulsation in the pedal) OR perhaps in the process of bedding it helped remove the air out of the brake system.

I'm more leaning toward air in the system perhaps in the ABS module which is very hard to get rid off unless you have a tool to activate the ABS module while pressure bleed the brakes.

I will try to pressure bleed the brake and see if I can get rid of the last 25% remain vibration.

What do you guys think?

Great!
I just bled my brakes last weekend.
I could not believe how bad the brake fluid was in there...
The brake pedal is better...

Solo12 06-13-2012 07:45 AM

I thought I had read something on the m5 board about a certain brake pad that people had used to clean up rotors from others pads that had put uneven deposits on the rotors. I could not find the thread, but I did find this re-posted response from Dave Z regarding high speed vibration in my search which may be helpful to you.

Scroll down to post #16 it won't let me link a single post for some reason
http://www.m5board.com/vbulletin/e39...ml#post2199728

It mentions
  • Traction strut bushing as a potential source of vibration (not even sure what that is perhaps another name for one of the bushings you already checked)
  • Brush attachment for an electric drill to clean the rotors
  • Hawk Blue race pads as a more expensive way to clean the rotors

Dave Z's response is pretty detailed so it might be helpful to you. Also the rest of that thread may also be useful

doru 06-13-2012 07:59 AM

Alex, check this post.

Fudman 06-13-2012 09:39 AM

Quote:

Originally Posted by 16valex (Post 6892659)
This morning.
-Checked strut mounts nuts. Nice and tight.
-Checked front rotors. They're beautiful looking, a uniformed gray color across, no visible hot spots or glazing of any kinks.
-Checked calipers bracket housing. Nice and tight.
-Checked calipers hanger rods. Nice and tight.

Went out and performed the zeckhausen brake bedding procedure.
The vibration has cut down drastically, not as sensitive as before when as soon as I touch the brake pedal the vibration was instantly vs now it would take about an inch down before the vibration kicks in but at a 25% scale of violence.

Now I'm not sure if the bedding procedure helped flatten the high spots (which I didn't see any to begin with or felt the pulsation in the pedal) OR perhaps in the process of bedding it helped remove the air out of the brake system.

I'm more leaning toward air in the system perhaps in the ABS module which is very hard to get rid off unless you have a tool to activate the ABS module while pressure bleed the brakes.

I will try to pressure bleed the brake and see if I can get rid of the last 25% remain vibration.

What do you guys think?


If rebedding partially fixed the problem, it is likely deposits on the rotor are what is causing the vibration. When you rebed your pads, could you smell them? If not, go back and do it again until you can actually smell them. I used to have to rebed my previous pads regularly to eliminate squeaking.

doru 06-13-2012 10:24 AM

Another thought about bedding:
If they are ceramic pads, i would not bed them - did it to my Akebono and lost total braking power one morning - the pads were glazed (bed them until they smelled....). Once the glazing was lost they performed OK.
If you have ceramic pads, I don't think they form deposits like the metallic pads. If this is the case (ceramic) look into my link above (rebuild calipers) or as other mentioned - resurface the rotors.

16valex 06-13-2012 01:18 PM

Quote:

Which car is this: the 528 or the 530? Is your brake pedal a little squishy?
John, it's the 530, and no squishy or spongy brake pedal.

Quote:

Dave Z's response is pretty detailed so it might be helpful to you. Also the rest of that thread may also be useful
Solo12, Both control arms are less than 10K miles, they are Loemforder OES, they are gootten tight!

Quote:

If rebedding partially fixed the problem, it is likely deposits on the rotor are what is causing the vibration. When you rebed your pads, could you smell them? If not, go back and do it again until you can actually smell them. I used to have to rebed my previous pads regularly to eliminate squeaking.
Fred, I could smell them during the bedding.

Quote:

If you have ceramic pads, I don't think they form deposits like the metallic pads. If this is the case (ceramic) look into my link above (rebuild calipers) or as other mentioned - resurface the rotors.
Dorin, Yes I do have ceramic pads and yes they are Akebonos.

I don't think my rotors are warped hence no pulsation in pedal during brake.
I think I have air in the system caused the brakes to grab un-evenly and intern it has caused the the vibration.

I will try to get the brake pressure bleed sometime soon, if that doesn't help then I will probably going to rebuild my calipers. It looks easy enough. Thank you

cn90 06-13-2012 04:12 PM

I guess one can do all that bedding business by zeckhausen, which I find useful ONLY if you deal with brand-new pad/rotor.

With worn-in pads/rotors, in 99% of the cases, it is warped rotors. Resurface them and you are good to go.

In my case:
Sept 2009: new rotor
Sept 2010: vibration w/ braking, resurfaced rotors.
Now...smooth like silk 2 years later.

AnotherGeezer 06-13-2012 04:27 PM

Hope you get it worked out Alex.

POof540i 06-13-2012 04:47 PM

Thread hi-jack in progress
 
Quote:

Originally Posted by cn90 (Post 6893812)
With worn-in pads/rotors, in 99% of the cases, it is warped rotors. Resurface them and you are good to go.

Can slotted and drilled rotors be resurfaced?


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