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front brakes dragging?please help!

bcmaxx

NAXJA Forum User
Heres my story:1989 cherokee 4dr non abs. Brakes felt very spongy,I found both rear wheel adjusters seized so I replace them shortly after my brake booster started leaking vacuum so I replaced it with a new one, soon after I noticed my front brakes were feeling pretty warm after a drive so I loosened of the master push rod and it seemed to fix it for a while. Strated dragging again so I replaced front calipers and hoses,blew out the lines with compressed air and bled the brakes. fine again for a while and back to smoking brakes and blue rotors.installed a new master cylinder bled and same damn thing.I'll be driving along and the pedal gets rock hard, I have to stop and pull the master cylinder and screw the master push rod in to get home and deal with the brake pedal almost hitting the floor. Can a booster do this? I imagine the brake pedal goes from mooshy to rock hard because the brakes are dragging and boiling the brake fluid. hopefully someone has had this happen and knows the fix. Thanks for reading :doh: my long boring story
 
how do i create a thread? Sorry this has nothing pertaining to your question, but I can't figure it out and support wont email me back.
 
Sounds very much like the proportioning valve. The "O" ring inside on the piston may be worn. I don't quite understand the mechaincs as to why, but it seems as if it won't let the pressure bleed back off into the MC and it seems as if the rear brake portion causes it.

In my case, I bypassed the rear brakes and put in a manual proportioning valve for them and left the front alone.

In your case, a new proportioning valve may be in order. When installing one, make sure to bleed it first throught the front bleeder screw (under the rubber cover).
 
well looks like i'm picking up a proportioning valve
 
was there any fluid on the back of the MCyl when you removed it? If so, it can destroy a booster in short order. I don't think it has anything to do with the breaks being stuck "on", but if it was wet-- change the booster again now that you've changed the M.Cyl.

--Shorty
 
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