Brakes sticking and engine revs rising under braking?

[Etype1967]

Hello to all.

I am again very appreciative to this forum.

I am again working on my series 1 4.2. This time my brakes are not fully releasing / getting stuck on after starting and I believe it maybe something to do with the vacuum assist r the master cylinder on the brake servo. The car revs are jumping up a bit when I apply the brakes combined with a hissing noise. This is new. After I turned the car off I can hear the vacuum system make a hiss and a pop noise sometimes.

Is this a leaking vacuum problem causing the locking? Should I be removing and investigating this? Or does this sound like a master cylinder issue sticking?

Some help in focusing on the issue to fix this would be greatly appreciated from this learned bunch.

I should note on the weekend I did bleed the braking system. This did flush the lines and the brake travel seemed fine during the process.

Thanks again.

Frustrated but persistent!

[abowie]

Maybe 2 problems.

Brakes sticking on is often related to the reaction valve at the front of the master cylinder sticking.

It has a tiny piston in it. You need to lubricate this generously with brake grease. Search the site for detailed instructions.

Revs changing with brake application might indicate a vacuum leak. First thing to do is disconnect the vacuum line from the inlet manifold and plug it off and see what happens to revs. If this fixes the problem you need to ascertain where in the brake vacuum system the leak is. Hoses, one way valve, servo or brake Reservac canister could all be implicated.

If you get into strife both Spiteri's and Mike Roddy are very knowledgeable, although not cheap.

[Etype1967]

Thank you,

After reviewing some of the forum posts; I fear you maybe correct and I have now confirmed my first suspicion. I think I possibly have 2 problems to deal with.

I have some work to now.

Thankyou again.

I will update on progreess through these issues.

[Etype1967]

Disconnected the vacuum line from the manifold. Works now without the booster. Just push the brake harder.

Narrowed what to rectify. Thank you.