Morris Minor Owners Club

Check the clearance between the master cylinder and the rod, same type of thing happened to me when I fitted marina brakes, opening the clearance to about an inch solved it, worth a look.

I've got exactly the same problem with my Traveller.It has standard brakes with a servo.

Yesterday i removed and checked the one way valve that is situated in the vacuum pipe

between the servo and manifold. To say the least it seemed to be sticking so i replaced the pipe

minus the valve and gave it a short run. The problem had gone and the brakes actually felt better.

My question is; What is the purpose of the one way valve when it doesn't seem necessary?

Am i missing something? Many thanks for your comments

May be to stop petrol being pushed into the servo in the event of an 'overpressure' (ie backfire) in the inlet manifold.

With response to the original poster, try 'bleeding' the servo outlet, and might aswell the inlet too whilst your at it, has solved the issue I had with the servo sticking on initially.

Without the check valve, if the engine dies, you lose ALL vacuum in the servo. With the check valve, if the engine dies, you have a small reservoir of vacuum in the servo, enough for one or two brake applications before you have to really stand on the brakes to make them operate.