My niece was driving their extra car ('85 300D) home a while back. She pulled over because the car did not have enough power to climb the grade on Cajon Pass (3,500'). It seemed like the rear brakes were on. When she stopped, she noticed that the rear brakes were smoking. She had the car towed home. A couple days later, my brother drove the car and everything worked fine. A couple days after that, he drove it and noticed the pedal going to the floor and barely stopping. He had the car towed to my house yesterday. I noticed brake fluid leaking from both rear calipers, so I replaced them with a pair of good used ones. I also put on a pair of turned rotors as well as new pads. Now comes the weird part. I successfully bled the rear brakes, and moved to the front. When doing the passenger side, I noticed (heard) bubbles in the fluid reservoir. I was able to get all the air out of that side, and moved to the driver side. I noticed the same bubbles in the reservoir when pushing down on the brake pedal. After bleeding the brakes, I test drove the car. It seemed to stop just fine. I was able to skid the front tires, and I imagine that the rears will get better as the pads wear in. However, the bubbles still concern me. Could there be something amiss with the master that would have caused the rear brakes to lock up in the first place? I will probably just replace the master for good measure anyway. I just don't want this to happen again......Rich

__________________

All Diesel Fleet
1985 R107 300SLD TURBODIESEL
2005 E320 CDI (daily)

LOTS of parts for sale!


EGR block kit
http://www.peachparts.com/shopforum/diesel-discussion/355250-sale-egr-delete-block-off-plate-kit.html

1985 CA emissions 617 owners- You Need This!
Sanden style A/C Compressor Mounting Kit for your 616/ 617 For Sale + Install Inst.

Sanden Instalation Guide (post 11):
http://www.peachparts.com/shopforum/diesel-discussion/367883-sanden-retrofit-installation-guide.html

I believe old brake hoses can sometimes cause calipers to stick.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

I have heard of that too, but one would think that condition would still exist.

__________________

All Diesel Fleet
1985 R107 300SLD TURBODIESEL
2005 E320 CDI (daily)

LOTS of parts for sale!


EGR block kit
http://www.peachparts.com/shopforum/diesel-discussion/355250-sale-egr-delete-block-off-plate-kit.html

1985 CA emissions 617 owners- You Need This!
Sanden style A/C Compressor Mounting Kit for your 616/ 617 For Sale + Install Inst.

Sanden Instalation Guide (post 11):
http://www.peachparts.com/shopforum/diesel-discussion/367883-sanden-retrofit-installation-guide.html

I won a lemon lawsuit against Ford Motor Company in the late 90s for a failed master cylinder causing exactly the same issues you describe above. They refused to acknowledge the issue or fix it, insisting on fixing other issues. Meanwhile, the brakes would continue to apply themselves and eventually stop the vehicle. I've never forgotten it, and I've never owned another Ford either. Bottom line - a MC problem CAN cause the brakes to hang up!

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Maybe the master cylinder forward piston isn't retracting when you release the brake pedal.

Sixto
83 300SD
98 E320 wagon

Bad master or swollen brake line, you have the two likely answers. Master maybe a bit more likely, since it releases by itself. One more possibility would be an air leak in the booster system, although this would affect the fronts also.