Brake problem

[mil_act02]

(This is an 81 CJ7.) They usually work fine, but on some off camber or steep terrain the pedal will go to the floor and there is little or no braking action. Most of the time when this happens I can pump the pedal a few times to get the pressure back. The last time it happened I was hung going up a hill and I could not get it to build up any pressure until I was pulled back down on level ground. The both reservoirs are full. This is the third master cylinder I’ve tried, and no leaks found in the system. Can the proportioning valve go bad? Any advice will help. Thanks

 

[apache]

Thats a strange one no doubt. The only thing I can think of is a air pocket in a wheel cylinder or caliper but thats a stretch as it should be there all the time. For maint sake Id invest in a Mighty Vac for one and flush/bleed the entire system and see if that helps.

 

[mil_act02]

Thats a strange one no doubt. The only thing I can think of is a air pocket in a wheel cylinder or caliper but thats a stretch as it should be there all the time. For maint sake Id invest in a Mighty Vac for one and flush/bleed the entire system and see if that helps.

Thanks, might have to try that.

 

[noJeepshere]

(This is an 81 CJ7.) They usually work fine, but on some off camber or steep terrain the pedal will go to the floor and there is little or no braking action. Most of the time when this happens I can pump the pedal a few times to get the pressure back. The last time it happened I was hung going up a hill and I could not get it to build up any pressure until I was pulled back down on level ground. The both reservoirs are full. This is the third master cylinder I’ve tried, and no leaks found in the system. Can the proportioning valve go bad? Any advice will help. Thanks

I wonder if on the off-camber stuff the brake fluid drains out of one reservoir and causes an air pocket that is removed by pumping the brakes on level ground.