Confirm Diagnosis

[kyreb1862]

When I press hard on the brake pedal in my 77B the idle speeds up. Am I correct in assuming that my brake booster has gone bad?

Regards John

 

[1965_MGB]

Hmm, that is a good question. It could be that the booster is gone, but it could also be a leak, maybe at the valve on the booster.

I can't recall exactly how to do it, but I know there is a test to see if the booster holds vacuum (from a pump or gauge like a Mitivac).

 

[Bruce74B]

or it could be wide feet ;-)

 

[DrEntropy]

check valve or booster. A vacuum pump is the best way to isolate which. It ~sounds~ like the check valve is the culprit.

 

[kyreb1862]

or it could be wide feet ;-)

Can't be that my feet are long but narrow. Size 12 C.