1967 250 SE Brake booster and master cilinder

[Alex Rozzi]

Hi Guys, I have almost finished water pump and thermost housing replacement, I finally bought zerex original formula due I contacted Stuttgart classic ccenter and they sent an edition of table 325.0 where this fluid appears homologated by Mercedes, I attach it and also attach an interesting article about coolant fluid: google "AntiFreeDec04" sorry too big file.

[Alex Rozzi]

sorry guys I forgot to change subject.

Im also working on brake booster reparation, I earing a shhh when brake applyed and engine start to run irregular, it seems vacum leak trough bosster diafragm, any tip to locate failure before starting diassemble?

some yaera ago I replaced master cilinder due leaks, I installed a little smaller VW pump, so you need a little more piston travel to get pressure on lines, now Im thinking it was an erro and too much travel ruined rubber diafragm, anybody did repair diafragm with cianocrylate adhesive? or rectified master cilinder? I planning doing that and insert a linner.

[TommyMacDaddy]

There is a small rubber seal between the booster and master cylinder. This may be the root cause of your issue. Mine failed and nearly sucked all of the brake fluid out of the master. The initial issue (which I mistakenly ignored) was that the engine speed would increase if the brake pedal was depressed with the engine idling.

I would suggest putting the correct master back on at the same time.The master was sized for travel, pressure and flow based on the requirements of the calipers, weight of the car and the pedal feel/travel.

Good luck!