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 > Diesel Discussion

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 07-09-2008, 11:28 PM
Registered User
 
Join Date: Jun 2008
Location: san diego
Posts: 6
Unhappy Break issue/I'm an idiot

So I successfully changed the front right wheel bearings on my '85 300D. However, being a complete novice/retard, I took the caliper apart (undid the 4 bolts that hold the two halves together instead of the 2 mounting bolts). I'd say about 4-8oz of fluid leaked out before I had it all put back together. After immediately detecting that the front brakes weren't working properly or at all, I topped off the fluid in the rear half of the reservoir and bled the system as described in the haynes book. Still not working. Did I ruin the caliper, do I need to bleed more (we pushed the brake pedal down 6-8 times to expel air, releasing once the master cylinder inlet hole for the front right weel was sealed by my finger - plenty of fluid was spewing out by the end), what have I done?!
So bummed out, any advice is greatly appreciated.

Reply With Quote
  #2  
Old 07-09-2008, 11:53 PM
Registered User
 
Join Date: Sep 2004
Posts: 8,971
Quote:
Originally Posted by lurob View Post
Did I ruin the caliper?
Technically, yes. The caliper halves should never be separated. So the safest thing to do is replace the caliper. And good practice requires that the caliper on the opposite wheel also be replaced.

Practically speaking, folks have successfully reassembled calipers. If yours doesn't leak and safety is not your top priority, you might get away with bolting it back together. Then bleed both front calipers. But first get a piece of clear PVC hose to attach to the bleeder screw so you can actually see that all the air has been bled out; the "finger" technique doesn't work very well.
Reply With Quote
  #3  
Old 07-09-2008, 11:57 PM
Caduceus's Avatar
123 Or Bust
 
Join Date: May 2007
Location: The Great North
Posts: 143
You can expect to push the pedal down a whole lot. When I replace my fluid I probably push it down a good 20-30 times per wheel. So with that much air let in I would say to just keep bleeding the whole system. LOTS of air is going to slowly come out.
Reply With Quote
  #4  
Old 07-10-2008, 12:29 AM
Registered User
 
Join Date: Jun 2008
Location: san diego
Posts: 6
ok, thanks for the advice. i'm a little confused about the bleeder screw. this is on the master cylinder?
Reply With Quote
  #5  
Old 07-10-2008, 12:30 AM
Registered User
 
Join Date: Sep 2004
Posts: 8,971
On the caliper.
Reply With Quote
  #6  
Old 07-10-2008, 05:21 AM
Registered User
 
Join Date: Dec 2004
Location: Nashua, NH
Posts: 3,956
You're far from the first person to inadvertanty unbolt those 4 bolts. If you were careful and kept the seam clean when you rebolted it there is no good reason why it should not be usable. I'd suggest trying to bleed it again and once it is bled right then check it for leaks. If it is not leaking at the seam there is no reason to replace it.
__________________
Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz
Reply With Quote
  #7  
Old 07-10-2008, 10:11 AM
I'm thinkin, I'm thinkin.
 
Join Date: Jul 2003
Location: Arlington, Texas
Posts: 440
When I replaced my right front caliper and all 4 brake hoses, I wound up having to bleed the system twice AND crack the lines at the master cylinder as well before I got my solid pedal back.
__________________
Sharing my partner's 2012 Forte 5dr SX til I find my next 123 or 126..
-
Do I miss being a service advisor ???
Reply With Quote
  #8  
Old 07-10-2008, 02:56 PM
Down South GA Boy
 
Join Date: Apr 2008
Location: Atlanta GA
Posts: 116
I fill a small cup with brake fluid and put a hose going from the bleed nipple down below the surface of the brake fluid in the cup, then keep the reservoir topped up and pump away, that should keep air from getting back into the system through the bleed nipple and I just pump until there are no more bubbles coming out. also bleed the brake farthest from the reservoir first.
__________________
'81 300D - swapped to a 617.951 turbo motor with a 150 amp alt.
Reply With Quote
  #9  
Old 07-10-2008, 07:58 PM
tyl604's Avatar
Registered User
 
Join Date: Feb 2008
Location: Atlanta, GA
Posts: 3,640
I think you can build a caliper rebuild kit. Is this not an option?
Reply With Quote
  #10  
Old 07-10-2008, 08:07 PM
Registered User
 
Join Date: Sep 2004
Posts: 8,971
Quote:
Originally Posted by tyl604 View Post
I think you can build a caliper rebuild kit. Is this not an option?
"Rebuild" is a bit of an exaggeration. The "kit" consists of new piston seals, dust boots and sometimes heat shields. Repair of disassembed caliper halves is not part of the deal.

Last edited by tangofox007; 07-10-2008 at 08:15 PM.
Reply With Quote
  #11  
Old 07-10-2008, 08:47 PM
arkie's Avatar
Frequent lurker
 
Join Date: Sep 2003
Location: Marion, Arkansas (near Memphis, TN)
Posts: 245
Search "gravity bleed" - works like a charm. I have done it after replacing calipers, left them bone-dry and just cracked the bleeders one at a time. The key is to NEVER let the reservoir go dry and be patient. It takes about an hour but works better than other bleeding methods IMHO.

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 03:49 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2024 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page