master cylinder failure?

[Andy Watson]

Crazy I know, but as it was a lovely day, I though I'd spend the afternoon in the garage changing the brake fluid. I'd flushed to two corners but on working on the off-side rear, the brake pedal was no longer pumping through fluid. Even on tightening the bleed nipple, the brake pedal still went straight to the floor. No fluid leaks in evidence so I guess there's a problem in the master cylinder. It's a year 2000 car, so should I just go for a new cylinder rather than renew the internals?

 

Andy

[Shad]

Sometimes if you pump fluid through using the pedal, and the pedal travels further than normal, it can damage the seals in the master cylinder as they travel past an area they don't normally. If you see what I mean.

 

Usually fixable with a seal kit to rebuild the master cylinder, if that's the problem.

[Andy Watson]

Ah, I see. Any idea what the master cylinder is from? Sierra?

[Z3MCJez]

I have a standard master cylinder that I took off my race car when I upgraded. It was used for 4 years, with no problems and fluid changed at least every year. I don't know if it's exactly the same, but blatmail me if you're interested.

 

Jez

[Phil B]

Andy,

 

Suggest you buy a Gunson Eezibleed to do this job once you've fixed the master cylinder. It avoids the need to pump the brake pedal and makes for an easy 1 man job. Just make sure you keep checking that the reservoir bottle is topped up and don't use more than 10psi tyre pressure (even though the instruction say you can use up to 20psi).

 

Phil

[Andy Watson]

....sounds like a good idea, if knackering the MC seals is a possibility..no matter how remote.