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 12-10-2007, 03:44 AM
Registered User
 
Join Date: Nov 2007
Posts: 18
1982 240d rear brake problem

I recently bought a 240d with a lot of delayed maintenance. At least one rear brake was not working. I replaced both rear calipers, pads and bled them quite a bit two different times. Pumping the brakes sends brake fluid out the bleeder however apparently not enough to lock up the brakes. What should I do next? Master cylinder?
Reply With Quote
  #2  
Old 12-10-2007, 04:57 AM
ForcedInduction
Guest
 
Posts: n/a
You should flush the system with a bottle or two of fresh fluid first. Then, the MC.

How well does the car stop?
Reply With Quote
  #3  
Old 12-10-2007, 05:52 AM
toomany MBZ's Avatar
Registered User
 
Join Date: Nov 2006
Location: central Va
Posts: 7,820
Yes, the brakes won't lock up when bleeding.
Good on the replacing calipers, test drive, and compare to previous brake feel, stopping power.
__________________
83 SD

84 CD
Reply With Quote
  #4  
Old 12-10-2007, 06:36 AM
t walgamuth's Avatar
dieselarchitect
 
Join Date: Apr 2005
Location: Lafayette Indiana
Posts: 34,123
I don't understand your problem. when bleeding them why would you try to lock them up. I think maybe you are not bleeding them correctly. In any case if you have a good firm brake pedal you are fine.

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
  #5  
Old 12-10-2007, 07:25 AM
ForcedInduction
Guest
 
Posts: n/a
I think he means they are receiving fluid while bleeding but they are not getting any pressure to stop the wheels when he is not bleeding them.
Reply With Quote
  #6  
Old 12-10-2007, 07:33 AM
JimFreeh's Avatar
Benz addict
 
Join Date: Mar 2007
Location: Hampton Roads, Virginia
Posts: 3,311
Quote:
Originally Posted by ForcedInduction View Post
I think he means they are receiving fluid while bleeding but they are not getting any pressure to stop the wheels when he is not bleeding them.

This can happen if the master cylinder runs out of fluid while bleeding, and you can get an air bubble. Might need to pull the lines at the MC and "bench bleed" the master.

Jim
__________________
14 E250 BlueTEC black
94 E320 Cabriolet Emerald green
85 300TD 4 spd manual dark blue
Reply With Quote
  #7  
Old 12-10-2007, 10:56 AM
Registered User
 
Join Date: Nov 2007
Posts: 18
I will bleed the brakes some more this evening

The problem is that once I am done bleeding the brakes the rear brakes still do not work. I have the 240D on jack stands and while the engine is running my wife has the brake peddle fully depressed and I can physically turn the rear tires - the rear brake does not lock up. Right after installing the new rear calipers, pads and bleeding the brakes lines I test drove the 240d and while the front brakes continued to work well the rear brakes didn't work at all - this is easy to tell when the roads are icy, the vehicle is stopped and the rear wheels continue to turn on the ice. I will let the brakes lines drip bleed this evening and run some more DOT4 fluid through to make sure there is no air in the system. However if air in the system is not the problem what should I try next?
Reply With Quote
  #8  
Old 12-10-2007, 11:11 AM
Biodiesel300TD's Avatar
|3iodiesel300T|)
 
Join Date: Dec 2004
Location: Albany, OR
Posts: 4,845
The brake fluid reservior has a front and rear compartment in it. Sounds like maybe you emptied the compartment for the rear brakes, which I believe is the front compartment. I've done this too. You have to completely fill up the reservior to fill the front compartment. Might check that out. If the reservoir is clean you can see both levels if you look closely.
__________________
Andrew
'04 Jetta TDI Wagon
'82 300TD ~ Winnie ~ Sold
'77 300D ~ Sold
Reply With Quote
  #9  
Old 12-10-2007, 12:34 PM
Registered User
 
Join Date: Sep 2004
Posts: 8,653
Quote:
Originally Posted by Alaska240D View Post
However if air in the system is not the problem what should I try next?
Reference the new calipers, are the bleeder valves on the top or the bottom?
Reply With Quote
  #10  
Old 12-10-2007, 12:50 PM
Registered User
 
Join Date: Nov 2007
Posts: 18
I have been filling the reservoir

It is possible that the reservoir was sucked dry the first time I bleeded the rear brakes after installing the new calipers and pads. However since then I have been very carefull to keep the reservoir (I noticed the split compartments early on) topped off while bleeding the brakes. While the engine was runing, 1. my wife would depress and hold the brake pedal, 2. I would loosen the rear bleed nipple - break fluid would squirt and drip out - and then I would tighten the bleed nipple, 3. my wife would then slowly release the brake pedal. This process was repeaded over and over again on the back and front brakes. In comparison the front brake fluid would squirt out with a lot of force and volume while the rear brake fluid would barely squirt out and mostly dribble out. Once the rear brake bleed nipple is tightened the force transfered through the brake fluid to the calipers/pads is insuffient to lock up the tire, to the the extent that I can physically turn the tire by hand (only a little brake pad resistance) while my wife has the brake pedal fully depressed. I am trying to figure out what is wrong here, either I still have air in the brake lines or something else is wrong. The rear brakes were not working when I picked up the vehicle, so I do not know if it had more problems than just the rear calipers and pads. The front brakes appear to work well.
Reply With Quote
  #11  
Old 12-10-2007, 12:56 PM
Registered User
 
Join Date: Sep 2004
Posts: 8,653
Sounds like you might need new hoses on the rear. Sometimes they swell internally and restrict flow. Also make sure they are not twisted or kinked. Same with the hard line-check for damage.

Is the pedal firm when the brakes ae applied?
Reply With Quote
  #12  
Old 12-10-2007, 12:56 PM
vstech's Avatar
DD MOD, HVAC,MCP,Mac,GMAC
 
Join Date: Mar 2006
Location: Mount Holly, NC
Posts: 26,286
this sounds like you have plugged lines, or damaged flexible lines. I would pull the flex lines and replace them.
__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!
Reply With Quote
  #13  
Old 12-10-2007, 03:17 PM
Registered User
 
Join Date: Dec 2005
Location: Carson City, NV
Posts: 3,771
I second replacing the soft lines. I did mine when I rebuilt the brakes on my '83. The hoses were like ten bucks apiece at NAPA and only added a few minutes to the total job.

If new hoses followed by a thorough bleed don't help, then it might be master cylinder time.
__________________
Anyone who thinks a 300D is fast drives too slow.

83 300D Turbo with manual conversion, early W126 vented front rotors and H4 headlights 357,xxx miles
08 Triumph Street Triple 24,xxx miles, lowered 10mm in front, Pirelli Angel GT tires, EBC HH brake pads, otherwise stock.
Reply With Quote
  #14  
Old 12-11-2007, 12:19 PM
Registered User
 
Join Date: Nov 2007
Posts: 18
The bleeders on the ATE rear calipers are on the bottom.
New brake lines have been ordered. The old ones are not kinked.
The brake pedal is firm when pressed. The front brakes work fine.
I allowed each caliper (one at a time) to drip bleed about 20 minutes each last night and I did not test the rear brakes yet.
How should I diagnos a malfunctioning master cylinder?
Reply With Quote
  #15  
Old 12-11-2007, 12:28 PM
Registered User
 
Join Date: Jan 2000
Location: PA
Posts: 5,440
Alaska,

The bleed screws have to be on the top to get the air out of the calipers. Sounds like U reversed the R and L calipers .

Reverse them again and see if your problem goes away. If problem goes away, hit your self in the head with a hammer so U remember to never do that again. LOL

P E H

Last edited by P.E.Haiges; 12-12-2007 at 11:17 AM.
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 10:46 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2019, 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