(83 240D)
I have to pump brake fluid into my slave cylinder with a hand pump every week or the transmission starts to lock up. I didnt think it was a bad Master Cylinder because my brakes are rock hard. I do think its a bad bleed valve because I notice it only takes a tweak to loosen it and so much effort to close it that last time I used (g__ forgive me) vice grips. This morning i had to use my wifes car thereby losing my bet with my neighbor that my 186,000 mile $2200 Benz would be more reliable than her 1999 Cavalier. PLEASE HELP--have to go to NYC this weekend.

Where exactly are you pumping brake fluid into your clutch slave cylinder?

A MY '83 240D with manual transmission is equipped with a brake master cylinder and a clutch master cylinder, both which share a common fluid reservoir. A cloth-braided fluid line coming off the left side of the brake fluid reservoir supplies the clutch master cylinder; a fluid leak anywhere in the clutch hydraulic circuit will lower the fluid level in the reservoir without immediately adversely affecting the brake system. Once the fluid falls below the level of the supply port, air is introduced into the clutch's master cylinder fluid supply hose.

If your clutch hydraulic system is loosing fluid, inspect the entire circuit to locate any leak(s). As you know, visualizing the clutch master cylinder will require removal of the driver's side lower dash panel. Is brake fluid leaking from the slave's bleeder screw? from the slave's push rod/rubber seal? from the clutch's master cylinder?

Bleeder valves should open and close easily, without vice grips. Are the threads on your bleeder valve rusted? Does the valve seat fully? If the valve is not seating, you'll see fluid loss. If you feel the slave is functionally intact and the slave's bleeder valve bore undamaged, then replace the bleeder valve. If the valve is rusted, the valve bore damaged or there is high mileage on the existing slave, then consider renewing it: # 001 295 68 07, up to chassis # 219674; otherwise, # 201 290 03 11. Approx. $91 from M-B. Part number for the clutch master cylinder - 001 295 44 06; approx. $99 from M-B. Don't forget to inspect the fluid supply hose originating at the master cylinder fluid reservoir; replace if necessary.

Finally, if master or slave cylinder renewal is required, ensure that the brake's master cylinder fluid reservoir seals are not fatigued and the reservoir is CLEAN, prior to filling with new DOT 4 brake fluid.

[This message has been edited by jgl1 (edited 04-05-2000).]

Thank you very much for taking the time to respond above.

I hope you know that the two master cylinders are different. There is one for the clutch inside the car and one for the brakes on the outside. The clutch is an entirely different system than the brakes, thier only common factor is the brake RESERVOIR. If you have no leak of fluid from the bottom, you probably have a faulty master cylinder. (it is inside under the kick panel/

------------------
Benzmac:
Donnie Drummonds
1981 280GE SWB
1987 16V
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM

Thanks, Benzmac I've been through the entire system. I tried adjusting the eccentric bolt; readjusted the spring, pumped new fluid into the system like you're supposed to through the slave cylinder, replaced the linkages with a set from another car, (and pulled the cylinder from the kick panel so I can reuse it) I suspect hose leakage, but I am going to rebuild the entire system. Obviously I am not German, but I try to be when it comes to thoroughness in repair.Thank you very much,Richard Chang

quote:

---

Originally posted by Benzmac:
I hope you know that the two master cylinders are different. There is one for the clutch inside the car and one for the brakes on the outside. The clutch is an entirely different system than the brakes, thier only common factor is the brake RESERVOIR. If you have no leak of fluid from the bottom, you probably have a faulty master cylinder. (it is inside under the kick panel/

---

As an added clarification, the slave unit
is located at the clutch yoke. Called extractor cylinder.
The unit at the pedal is the suppy cylinder,
not the slave . Or clutch master.