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 12-22-2006, 10:10 PM
Registered User
 
Join Date: Dec 2000
Location: Mt. Airy, Maryland
Posts: 116
Is this possible?

Hi my friend has a 2004 Passat. He had it in the dealer for some work and they said he needed new rear brakes and the system should be bled. They quoted him $650.00. We replaced the brake pads and I pumped the brakes to firm everything up. Then we were going to bleed the system and add new fluid. With the engine off I had my foot on the pedal (with really just the weight of my foot with no pumping) and he loosened the bleeder valve and no fluid came out. So we tried the other side thinking something might be wrong with the one and same thing no brake fluid came out. So we decided to forget about bleeding the brakes. When we started the car up the brakes worked fine, but if you stopped and kept your foot on the brake pedal your foot would slowly go to the floor. Like the master cyclinder went bad. We tried bleeding the brakes again with the motor running this time and fluid came out. My question is. Is it possible to damage the master cyclinder by trying to bleed the brakes without the motor running? In the past I have always bled brakes without the motor running.
Thank You

__________________
Mike
Reply With Quote
  #2  
Old 12-22-2006, 10:44 PM
t walgamuth's Avatar
dieselarchitect
 
Join Date: Apr 2005
Location: Lafayette Indiana
Posts: 36,308
i wouldnt think so.

but i have no experience with vws.

did he get a quote from the dealer saying what they were going to do? and did you do that instead?

tom w
__________________
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.
Reply With Quote
  #3  
Old 12-22-2006, 11:13 PM
dkveuro's Avatar
Sword of Damocles
 
Join Date: Jun 2003
Location: Here an' there.
Posts: 2,548
It has often been my observation that when bleeding a brake system, the master cylinder will fail on older vehicles.
This is due to the silt build up in the reservoir...a combination of oxydized fluid and rust from the systems internals.
Mercedes seem prone to this too.

VW does this a lot if the vehicle is 6 years old or more.
To stop/reduce this happening I now remove the reservoir and flush it out...refit and fill with clean fluid.

The 'slow' sinking of the pedal is the hardening of the umberella cup seals and then being hard, the washed down debris from the bleeeding score the cup seal lips....some times you can stamp the brakes real hard and quickly, and then get a firm pedal...this confirms bad cup seals.

VW Passat: Rear brake pads, instal/parts...$165.00.
If the car is ABS equipped you need to activate the ABS pump.

However...NEVER push back the fluid by retracting the caliper piston/s with out bleeding the fluid out through the bleeder as the old fluid can and will cause problems in the ABS unit.

Reverse flushing the ABS has killed many systems.


.

.
__________________
[http://languageandgrammar.com/2008/01/14/youve-got-problems-not-issues/ ]

"A liberal is someone who feels they owe a great debt to their fellow man, which debt he proposes to pay off with your money."

Last edited by dkveuro; 12-22-2006 at 11:18 PM.
Reply With Quote
  #4  
Old 12-22-2006, 11:14 PM
Registered User
 
Join Date: Oct 2005
Posts: 4,263
Check the TDI forum. I think I recall reading something about bleeding the brakes using the diagnostic computer to control the ABS pump.
Reply With Quote
  #5  
Old 12-23-2006, 11:37 PM
Registered User
 
Join Date: Dec 2000
Location: Mt. Airy, Maryland
Posts: 116
Thanks Guys. What is TDI forum?
__________________
Mike
Reply With Quote
  #6  
Old 12-23-2006, 11:53 PM
dkveuro's Avatar
Sword of Damocles
 
Join Date: Jun 2003
Location: Here an' there.
Posts: 2,548
Quote:
Originally Posted by Mike Michalek View Post
Thanks Guys. What is TDI forum?
http://www.tdiclub.com/




.
__________________
[http://languageandgrammar.com/2008/01/14/youve-got-problems-not-issues/ ]

"A liberal is someone who feels they owe a great debt to their fellow man, which debt he proposes to pay off with your money."
Reply With Quote
  #7  
Old 12-24-2006, 12:56 PM
t walgamuth's Avatar
dieselarchitect
 
Join Date: Apr 2005
Location: Lafayette Indiana
Posts: 36,308
dkveuro,
thanks for the tip about pushing the calipers back. i have always done this but probably not any of my cars so far have had abs. i will try to keep this in mind. cleaning the res sounds like good insurance too. i often suck them out with the baster, but that wouldnt get it all would it? is there a low area in the res that will collect debris and never empty fully?

tom w
__________________
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.
Reply With Quote
  #8  
Old 12-24-2006, 01:11 PM
dkveuro's Avatar
Sword of Damocles
 
Join Date: Jun 2003
Location: Here an' there.
Posts: 2,548
Quote:
Originally Posted by t walgamuth View Post
dkveuro,
thanks for the tip about pushing the calipers back. i have always done this but probably not any of my cars so far have had abs. i will try to keep this in mind. cleaning the res sounds like good insurance too. i often suck them out with the baster, but that wouldnt get it all would it? is there a low area in the res that will collect debris and never empty fully?

tom w
Tom...the res' has two chambers and the front one on the 123/126 etc is difficult to clean. I use a Water Pick in the shop bathroom to clean it out...have used hard rice in stubbon dirty res' to knock loose dirt....also with a few drops of Dawn or liquid Tide.....shake it like crazy and do over a couple of times.
....... blow dry with shop air and rinse out twice or more with brake fluid your going to use, to absorb the H2O....you'll know when it's clean.
Alternative is to buy a new res'....they come high$ with two float units per.

Mech' to owner some time later .." I think I found your brake problem sir..."
Owner.." Oh? What did you find."
Mech' .." Seems your car was owned by Asian people in the past " ....holding up rice grain.




.



.


.

__________________
[http://languageandgrammar.com/2008/01/14/youve-got-problems-not-issues/ ]

"A liberal is someone who feels they owe a great debt to their fellow man, which debt he proposes to pay off with your money."
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 11:04 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