Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help



Go Back   PeachParts Mercedes-Benz Forum > Mercedes-Benz Tech Information and Support > Tech Help

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 08-04-2010, 08:05 PM
Registered User
 
Join Date: Jan 2007
Location: Atlanta, GA
Posts: 219
W124 Braking Vibration

It's a 1994 E320 Wagon 124.092.

I had a bad vibration on the front rotors when braking so purchased new OE rotors(marked ATE on the stamping) and OE pads. The old rotors had some good mileage on them and were pretty badly glazed so I decided to replace with new. After changing everything out the vibration went away...at least when driving surface street speeds. It wasn't until about a week later on the highway that I noticed that there was still a vibration, at much faster pulsation, when braking. I have to be driving at least 55+ to really feel it. It's not as bad, but it's definitely there.

I'm wondering if the vibration is actually coming from the rears (vented on my W124)? or the rears were contributing to some of the vibration prior but I never replaced those so that's where I'm still feeling it from. If this is the case, I would be surprised. I've never had warped rear rotors before in any car or truck I have owned.

Is it possible that the rotors I bought from the dealer were bad? I've been told that quality rotors don't need to be "turned" as long as the braking system is working properly with no abnormalities.

Any thoughts?

Reply With Quote
  #2  
Old 08-04-2010, 10:10 PM
RobertFini's Avatar
Registered User
 
Join Date: Oct 2002
Location: Millville, NJ
Posts: 241
Hmmm...

Might maybe be a front wheel bearing or front tire problem, which becomes more obvious under braking as the weight transfers forward onto the front axle.

Try swapping the tires front-to rear and paying extra attention as you go around corners and the weight transfers left to right.

Best Regards,
Rob
__________________
Rob Fini

'07 E350T 4MATIC, 220k (wife's)
'06 E320CDI, 223k
'05 T1N Sprinter 2500/Pleasure-Way Plateau TS, 59k
'99 E320 4MATIC, 248k (dormant)
'97 C36AMG, 270k (son's)
'94 E320T, 249k
'93 190E Sportline LE, 168k (daughter's)
'84 190E-2.3/5spd (Stage Rally Racer)
'66 230 W110 Sedan (Barn Find, Vintage Racer build in progress)
Reply With Quote
  #3  
Old 08-04-2010, 11:23 PM
Registered User
 
Join Date: May 2007
Location: Arizona
Posts: 757
Try to stop just using the emergency brake with one had on the release handle. It would rule out the front brakes if there is no vibration.

Edited: On second thought, I'm not sure if the emergency brake controls the pads or just the shoes on the inside.
__________________
1993 400E, 256,000 miles (totaled)
1994 E420, 200,000+ miles
1995 E420, 201,000 miles

Last edited by emerydc8; 08-05-2010 at 06:38 AM.
Reply With Quote
  #4  
Old 08-05-2010, 06:36 AM
Registered User
 
Join Date: Jan 2008
Location: Melbourne Australia
Posts: 840
Test your lower ball joints or steering rods.
Reply With Quote
  #5  
Old 08-05-2010, 11:25 AM
Registered User
 
Join Date: Jan 2007
Location: Atlanta, GA
Posts: 219
Quote:
Originally Posted by emerydc8 View Post
Try to stop just using the emergency brake with one had on the release handle. It would rule out the front brakes if there is no vibration.

Edited: On second thought, I'm not sure if the emergency brake controls the pads or just the shoes on the inside.
Don't you mean the rear brakes? I don't think they grab the disc with the pads.
Reply With Quote
  #6  
Old 08-05-2010, 01:10 PM
Registered User
 
Join Date: Jan 2007
Location: Atlanta, GA
Posts: 219
Quote:
Originally Posted by Ivanerrol View Post
Test your lower ball joints or steering rods.
Steering rod, control arm, dampener - all replaced recently.

I'm down to:
Lower Ball Joints
Rear Disc

I went through the fronts again this morning. Unmounted everything, made sure rotors were seated flat, and everything torqued back to specs. Just for my own neurosis...

Anything other possibilities other than the two aforementioned?
Reply With Quote
  #7  
Old 08-05-2010, 01:16 PM
babymog's Avatar
Loose Cannon - No Balls
 
Join Date: Jan 2006
Location: Northeast Indiana
Posts: 10,767
I went through this on my first quattro, had 5 sets of rotors and pads under warranty, blamed my wheels (BBS), which dial-indicated to less than 10% of runout spec, they eventually replaced the hubs and bearings which cured my problem to run the next set of brakes for 130,000 miles.

If you have a dial-indicator, that would be your next step IMO. If not, try spinning the wheel with something propped close to the wheel and look for lateral and radial runout at the wheel and at the tire.

Often a slow swerve left/right as you're braking will make it better/worse to indicate which side is the offendor.
__________________

Gone to the dark side

- Jeff
Reply With Quote
  #8  
Old 08-05-2010, 11:24 PM
Registered User
 
Join Date: May 2007
Location: Arizona
Posts: 757
Have you tried replacing the horizontal damper in between steering ends? I don't know if it will solve the underlying problem, but it may make it less noticeable, and they only cost about $65. Have you cleaned the antiskid sensors on the front brakes? Metal deposits on the sensors caused a pulsation at very low speeds for me.
__________________
1993 400E, 256,000 miles (totaled)
1994 E420, 200,000+ miles
1995 E420, 201,000 miles
Reply With Quote
  #9  
Old 08-06-2010, 01:15 AM
Sev's Avatar
Sev Sev is offline
Infractions: 99/99 (999)
 
Join Date: Apr 2007
Posts: 1,461
you know how to check if the ball joints are bad, right? jack up the front, grab the tire at 3 o'clock and 9 o'clock and push one end forward and the other end toward you. if there's even a centimeter of 'play', the ball joint is shot and needs replacing.
__________________
i know Jim Smith. i don't actually know him, but I know of him
http://imageshack.com/a/img923/6201/RQ1H6A.jpg
Reply With Quote
  #10  
Old 08-06-2010, 06:08 AM
Registered User
 
Join Date: Aug 2002
Location: Southeastern PA
Posts: 3,052
Sev, I guess you meant so say " a mm of play". A cm of play would be awfully loose.
__________________
Fred Hoelzle
Reply With Quote
  #11  
Old 08-06-2010, 07:07 AM
LarryBible
Guest
 
Posts: n/a
Did you THOROUGHLY clean the mating surface of the hub with a steel brush before installing the new rotors?

Also do you use tire foam? I have started seeing more and more brake vibrations as the result of this stuff. What happens is that a little gets through the wheel spokes onto portions of the rotor. It acts a lubricant that coats the surfaces on only portions of the surface changing the coefficient of friction as the rotor turns against the pads.

If you use tire foam, make a cardboard cover that fits the wheel and hold it in place as a mask to ensure that no droplets of tire foam make it to the rotors.
Reply With Quote
  #12  
Old 08-06-2010, 09:14 AM
Registered User
 
Join Date: Jan 2007
Location: Atlanta, GA
Posts: 219
Dampener was replaced recently.

No play in the ball joint or runoff (checked with dial).

Yes, cleaned very thoroughly before mounting rotors.

What the hell is tire foam? I don't ever spray my tires with anything. Always cloth rag and apply.

Thanks for all the feedback. I'm starting to think it's the rear disc. It would be a first ever but I guess there is always a first for everything. What sucks is that since I have the vented rotors they are not cheap. What I may end up doing is turning the old ones to identify for sure that this is the problem and if so replace with OE if it is. Sounds like a lot of work buy I'm not going to drop dime on rear rotors only to find that wasn't the culprit.

Edit: I should add that after calling the three local MB dealers in the area and talking to the service manager they say a bad rotor, although rare, has happened to show up in their stock. So it is still possible that I may have a bad front OE rotor n

Any other ideas?
Reply With Quote
  #13  
Old 08-06-2010, 09:25 AM
Registered User
 
Join Date: Aug 2002
Location: Southeastern PA
Posts: 3,052
speed, it's not advisable to turn MB rotors. Not sure why you would install vented rear rotors. Solid rear rotors are stock as far as I know. Typically I buy new rotors from our local MB dealer, and have never had any quality or performance issues.
__________________
Fred Hoelzle
Reply With Quote
  #14  
Old 08-06-2010, 09:33 AM
Registered User
 
Join Date: Jan 2007
Location: Atlanta, GA
Posts: 219
Quote:
Originally Posted by Ferdman View Post
speed, it's not advisable to turn MB rotors. Not sure why you would install vented rear rotors. Solid rear rotors are stock as far as I know. Typically I buy new rotors from our local MB dealer, and have never had any quality or performance issues.
It's a 124.092 - aka wagon, and stock vented rear rotors. Only class of W124 with rear vented (well say for the W124.036). I understand and recognize about turning them but it's just to isolate the problem. It was actually a suggestion by the service manager at the MB dealer. Obvisously they don't turn them at the dealer so I'll have to take them to a service shop.

Edit: To clarify, the idea here is to turn the old rotors, remount and see if the vibration goes away. If it does, replace with OE. If not keep them on there as no harm is done (as long as I'm not below min spec). The rear rotors are more expensive than my front rotors, both OE. Go figure.
Reply With Quote
  #15  
Old 08-06-2010, 12:31 PM
Registered User
 
Join Date: Aug 2003
Location: Phoenix
Posts: 3,726
You're carefully torqueing the lug nuts to spec?

Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT -4. The time now is 07:07 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page