Morris Minor Owners Club

A brake servo problem?

The engine falters, then stalls on braking. It's not the lights draining on the battery. I can hear a hiss from the servo when the brake pedal is depressed. The hiss is slight on a partially depressed pedal and louder on a fully depressed pedal like a 'sshh' and you can hear the engine note change to lower revs then die. I have never noticed a hiss before, but I don't normally have the bonnet up while pressing the brake pedal, so don't know if this is normal. The brake pedal moves freely on its shaft.

Any ideas?

Idle too slow? The servo uses air pressure - so yes there will be a bit of a hiss - but it's not usually noticeable. Has the problem just started - or is it ongoing?

It was the servo!

Upon inspection it had a 5cm gash in the large rubber diaphragm. Replaced and brake feel now as good as new. Can even lockup the wheels using forceful pedal pressure now.

If the brakes are working as they should be - the wheels should lock WITHOUT a servo...........