After replacement of brake lines, I tried to bleed the system but after some
pumps on the brake pedal, at rear caliper starts to come out only air
regardless how long I pump.
Finally, I found that the problem seems to be in the master cylinder (made
by ATE). From the front line (secondary master cylinder) its pump only air,
whereas the rear line seems to be in order. There wasn't any resistance on
the brake pedal.
I disassembled the master cylinder but inside it's looked like brand-new. I
also tried a bench bleeding however, without success.
I suspected that the small valve on the front of the piston (that is
supposed to release the fluid to the secondary cylinder?) somehow doesn't
work even so that this valve also looks good. I tried to flush it with brake
fluid but without any effect.
Meanwhile a friend told me that with his 300E has happen the same.
Therefore, it seems not to be an isolate case.
I ordered already a replacement master cylinder but I'm still curious where
exactly is the problem and could it be repaired?
'91 MB 300TD turbo (603.960 engine)