Brake Help

Hello all,

I know it’s not really about early CJ5 except for that it’s on mine.

the PO put in an early 80’s import brake booster with 11” drum upgrades. I rebuilt all brakes, and master cylinder and replaced the brake booster with a rebuild from Cardone.

I’m trying to get it all bled etc abs noticed that the engine RPMs change when I press on pedal. I assume it has something to do with the vacuum but what?

 

Rpm goes up or down? Leaky boosters are a vacuum leak.

 

Up so since it’s a brand new rebuilt I guess it is a vacuum leak on hose?

 

Yep you got a leak somewhere. Just because its newly rebuilt doesnt mean anything anymore. The diaphragm could be bad, nicked on install etc. If it's a flaps piece just return / swap it.

 

So that means when I push on the pedal it’s pushing air into the manifold this increasing RPM?

 

More like allowing the manifold to suck in excess air, for as long as the leaky booster is activated by the pedal.