Re: brake question

Posted by HH56 On 2015/8/13 14:16:52

If the brake shoes are adjusted properly they don't move far so the pedal usually doesn't have to move more than an inch or two before brakes are applied. There is very little free play as compared to manual brakes. The pedal is directly connected to the rod so it only has to move maybe 1/8 inch before vacuum is started to be admitted to do the work. The pedal should move very easily and many complain that it moves so little and so freely that the brakes are applied too severely and it takes a very gentle touch to avoid meeting the windshield.

If the pedal is hard to move I would check vacuum. Pushing the pedal down, do you hear a whoosh or hiss as vacuum is allowed to enter the vacuum apply portion of power unit? If not, make sure there are no leaks and the check valve at the intake manifold is working properly. When the engine has been running, after turning it off there should still be enough vacuum held in the lines and reserve canister for at least two or three brake applications. The vacuum will eventually bleed off but not that fast if the lines and check valve are in good condition.