Rear brakes not working

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This has me stumped. My rear brakes on my Wrangler have stopped working. It's slowly gotten worse and now I can jack up the rear end, start it, put in gear, let the clutch out and stand on the brake pedal with all I have and the rears keep spinning.

The fronts will lock up very easily now. So far I have replaced the rear shoes(yes I know about primary and secondary shoes), Proportuning valve, both rear wheel cylinders.

The pedal feels normal. I've had a bad MC before and I know how that felt.

I have a new rubber line for the rear I'm going to put on. I've heard of internal failure but have never seen it myself.

I've adjusted the shoes up and the parking brake does work. I can lock the rears if I pull the parking brake hard when moving.

I ordered the Jeep W/O any antilock stuff so it does not have any of that.

Ideas?
 
Originally Posted By: flacoman
do you get a squirt of fluid from the bleeder screws?
Yes but more like a run. Doesn't squirt out like it should. Squirts fine at the MC.
 
Possible a bad proportioning valve, or a line that supplies both rear wheel cyls [since both don't work].
Maybe the master cyl.
 
How old is it?

I've seen that brake hose on the top of the rear end swell shut on old cars.
 
Originally Posted By: mechtech2
Possible a bad proportioning valve, or a line that supplies both rear wheel cyls [since both don't work].
Maybe the master cyl.
I've replaced the proportioning valve with no change.

There is a rubber hose that supplies both rear wheels. Ive got the line just have to put it on. I really don't think it's the problem. The pedal feels fine. Does not travel excessivly far or sink.


Originally Posted By: JakeR22
How old is it?




The Jeep is an 02 and I replace the fluid every couple of years. I replaced the rear cylinders thinking that they somehow could have been rusted. Once I took the old ones apart they looked brand new.
 
Originally Posted By: FusilliJerry82
Rusty/pinched brake line?
Not much rust in the desert
lol.gif


Pinched is a possibility I guess. No idea how it would have gotten pinched.
 
Tonight I replaced the rear rubber line. Still no rear brakes. I'm getting what looks like a good squirt out of the bleeders when I open them and the helper pushes the pedal down.

Rear shoes are adjusted up as tight as I dare. Any tighter and they will not turn by hand. With a helper pushing on the brake pedal I can still turn the rear wheels.

I'm stumped.
 
If you can have the vehicle off the road for a while, or if you aren't even driving it now, try this:

Disconnect every all the brake line connections.
Plug the master cylinder connections so it won't run dry.
Use compressed air and start blwing air though the lines starting with the lines at the master.
Do this at every connection and work your way to the back.

This should blow out any junk that might be clogging up a line or if a line is pinched.

Blow out the proportioning valve also.

If there's nothing obvious and everything is ok then fill it all back up and do a good bleed on the system.

If it's still the same after that then I'd be looking at the parts inside the drums and testing the MC to see just how much pressure it's putting out.
 
The problem should be with the MC ..but otherwise.....

Something with the front circuit may be preventing the mc from moving far enough to engage the rear fully. It's dead headed somehow. Don't ask me how, but that's the only place you've not explored.

How can you safely test this out (thinking) ..

..pull one or both pads but rig it somehow that the pistons aren't going to be able to blow out of the bore..

I still think it's the MC. Just because it doesn't leak down or pump up doesn't mean that the piston is sealing at all at the rear portion of the bore.
 
Originally Posted By: Chris142


There is a rubber hose that supplies both rear wheels. Ive got the line just have to put it on. I really don't think it's the problem. The pedal feels fine. Does not travel excessivly far or sink.




Replace the hose, this is most likely the culprit...they swell over time, and eventually swell shut...there is no external indication of a problem with the hose.

I have had three chrysler products all have this affliction (79 Ramcharger, 86 Ramcharger, and 1994 Ram 1500).
 
We have to concentrate on things that only affect the rear brakes, and both of them at the same time.
That leaves what mechtech said in a previous post.
 
Originally Posted By: mechtech2
We have to concentrate on things that only affect the rear brakes, and both of them at the same time.
That leaves what mechtech said in a previous post.



The rubber hose, between the frame and the axle, is a single point that WILL affect both wheels. We are not talking caliper hoses...but the single line that drops to the axle that supplies both wheels.
 
Originally Posted By: Gary Allan
The problem should be with the MC ..but otherwise...
If you changed out the proportioning valve recent that may be the best place to check for main flow from the rear section of the MC. The line doesn't even need to be removed just loosened. Next after the P. valve. The P-valve being a restriction any how make sure you have it in a open position to simulate a heavy load. Even fully open it will flow up to maybe 50% less than before the P. valve normally. the only thing left is the hose.
 
One thing to check would be to attempt to loosen a bleeder on the rear brakes (caliper/drum?) and see if you get a volume of fluid from them...if the rubber line is swelled, you should get very little pedal drop when the bleeder is cracked.

Another thing to consider is that the wheel cylinder/calipers have siezed, this is another common Chrysler issue on the 90s+ trucks. My 94, 99, and even this 04.5 experienced seized/stiff calipers.
 
Originally Posted By: deeter16317
One thing to check would be to attempt to loosen a bleeder on the rear brakes (caliper/drum?) and see if you get a volume of fluid from them...if the rubber line is swelled, you should get very little pedal drop when the bleeder is cracked.

Another thing to consider is that the wheel cylinder/calipers have siezed, this is another common Chrysler issue on the 90s+ trucks. My 94, 99, and even this 04.5 experienced seized/stiff calipers.
I replaced the line last night and the wheel cylinders 2 weeks ago.
 
He gets flow out of the bleeders. Not great, but flow. That should make any restriction merely a time difference. Just like one kinked hose on the front. It pulls one way on application due to slow filling. Then it pulls the other way due to slow releasing.

..but, hey, replace the hose..
21.gif
 
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