Brake master cylinder failure ?

[reetp]

Been noticing a lengthening brake pedal and first thought it was air in the brakes. Having checked this out, it would appear that the master cylinder is failing.

Can anyone give me chapter & verse on this ? Can I just get replacement seals or do I need a new unit.

Any suggestions as to where the best place is to get them ?

And help gratefully appreciated as ever !

B. Rgds
John

 

[R1cho]

are you sure its the master cylinder and that the rear brakes just dont need adjusting?

 

[reetp]

are you sure its the master cylinder and that the rear brakes just dont need adjusting?

Thanks for the prompt reply !

Ironically, I don't think so. Just had the seals go on one of the rear axles which dumped oil on the brakes so whilst doing the brakes the rear shoes and cylinders were changed - the cylinders had been a bit dodgy, but they are new ones now (literally a few days ago).

Just as an addendum. The pedal is very long and pumping it does not increase the pressure. If you pump it a couple of times & then hold the pressure, the pedal goes down.

As a thought, is it the master cylinder or could it possibly be servo related ?

AFAIA it doesn't have ABS (thank heavens !)

B. Rgds
John

 

[reetp]

P.S. It's a Lucas cylinder from the looks of the lid on the top...........

 

[reetp]

I was advised to try and keep steady pressure on the pedal with the engine off (once the vacuum had gone) to see if the pedal went down. Not a mm. Suggestion is (after discounting the refurbed back brakes) either a dodgy hose ballooning a bit or a badly seized piston causing the caliper for move.

Now, as it happens, I had one set of pistons with new seal last year as the brakes were binding on. I've been waiting to have the other side done - I know it's bad, but I think its maybe worse than I suspected.

So I'm going to get the tube & seals changed first, bleed it all & then check it again.

Will report back....... off to sort the bloody dishwasher now :-(

 

[reetp]

Hmmm.

OK, checked the other caliper (well my brother-in-law did who is a mechanic) and all was well. Changed the hose as we had it there so new front hoses both sides, calipers all free, new rear shoes & cylinders. All seem to be bled OK.

Engine off and the pedal is rock hard. Fire it up and it just goes gently down to the floor. So before I blow my brains out on a new master cylinder is there another answer or something to check ??

B. Rgds
John