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MG MGB Technical - Hard brake peddle 80 B

Greetings to the list,

The car is a 1980 N.A. MGB, L.H. steering, with servo attached to M/C.

Symptoms: Brake peddle is hard to depress, car will stop but seems to take longer without a good feel.

I checked reservoir and it's topped, all flex brake lines seem solid, no leaks or soft spots. But when I had helper depress peddle I noticed hyd.fluid running down servo, between servo and master-cylinder. I detached M/C from servo ( followed Haynes shop man.) finding fluid coated internal area of servo that I could see with servo in place, and around out side of cup seal on the end of the M/C. Also some rust looking matter on the rod coming from servo to M/C.

I'm not a brake specialist by any stretch, and the manuals I have (Haynes & Bently) don't tell me much, that I can understand.

I could use a bit of advice at this point, and any help that can be forwarded.

Thanks in advance,

Bob H.
Bob Holton

Fluid is not supposed to enter the Servo, unless
as you've found the MC itself is leaking. Probably
time for a new master cylinder, but check on rebuild
tips in the archives.

I've generally bought new cylinders, but you could
also try buying a rebuilt one from apple hydraulics
(www.applehydraulics.com.)
Ronald

Bob. Your hard brake pedal operation is symptomatic of a bad servo unit. Since it is not funtioning, the system requires significantly more effor to operate. The probable cause, from your description, is a leak in the master cylinder which may have caused a problem with the servo. You need to rebuild the master cylinder, if possible. If the bore is too rusted, it may be sleeved or replaced with a new master cylinder unit. The servo can be rebuilt. Les
Les Bengtson

This thread was discussed between 15/09/2001 and 16/09/2001

MG MGB Technical index

This thread is from the archive. The Live MG MGB Technical BBS is active now.