Cannot get rear brakes to apply

JIMMOLINARO

MEMBER
1993 JEEP WRANGLER
6 CYL
4WD
AUTOMATIC
76,000 MILES

I changed the front calipers and pads because they were severely burnt from an obvious seizing problem.
I also found partially restricted brake hoses on both sides which I assumed caused the burnt calipers & pads (discs not releasing all the way). So I changed both hoses. Then after an entire system bleed and a road test, the rear shoes refuse to activate and the vehicle lurches foward slightly when the brakes are applied. You could just feel the weakness of the rear shoes not applying. It is obviously a strained & uneven stop using only the front discs. Out of desperation I proceeded to change the proportioning valve that sits directly below the master cylinder. No luck. Same thing.
What seemed like a simple caliper/brk hose job has turned into a nightmare. Any thoughts on this?

1 Reply

KASEKENNY

MECHANIC
18,907 POSTS

First and foremost, we need to make sure they are operating as you are thinking it is.

Lift the vehicle and get it up to 25 MPH in the air and apply the brakes. Do the rear brakes stop the wheels?

https://www.2carpros.com/articles/jack-up-and-lift-your-car-safely

If not, then I suspect we have had brake fluid contamination and we may need to replace the master cylinder and flush the entire system. Also, we need to inspect the wheel cylinders to find out if they are leaking or the rubber is swollen.

https://www.2carpros.com/articles/how-to-replace-a-brake-master-cylinder

I am attaching the process from the manual that will help with this, but you need to make sure you have bled the master before installing it.

Please run through this and let us know what you find. Thanks

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