1988 Jeep Cherokee No Rear Brakes

1988 JEEP CHEROKEE
160,000 MILES • 6 CYL • 4WD • AUTOMATIC
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JACOBSPRODUCTIONS
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I have recently had all the brakes done on my 1988 Jeep Cherokee. We had replaced the front rotors and shoes. Then noticed that the rear brakes were not engaging. We replaced the rear wheel cyclinders, bled the lines and still no back brakes. We then replaced the master cylinder and rebled. Still no rear brakes. Just yesterday, we disconnected the rear brake line to double check we have good fluid flow to the back and got a healthy squirt of fluid when stepping on the brake pedal. However, there is still hardly any brake action on the back brakes. We plugged both master cylinder ports to double check the master cylinder and it checks good (super solid pedal). Plugged the rear brake port with front brakes attached, front brakes work fine. Plugged front brake port with rear brakes attached and the pedal is very solid, but no rears brakes are engaging. We have rebled numerous times. What else could be the problem?
Oct 10, 2008 at 10:35 AM
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DOCFIXIT
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May have a problem with the proportion/metering valve limiting pressure to rears. Do the wheel cylinders move ? And are rear linings adjusted to rub drum when turned?
Oct 10, 2008 at 10:55 AM
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JACOBSPRODUCTIONS
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The wheel cylinders do move...they were tested before putting the drums back on. The linings were also adjusted prior to installing the drums. How much pressure should be expected at the back and how would you measure it?
Oct 10, 2008 at 11:37 AM
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DOCFIXIT
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400 to 700 psi. it should shoot out bleeder with great force and travel several feet. If not the combo valve may have set and sealed pressure to rears.
Was there brake failure prior to repair?
Oct 10, 2008 at 12:20 PM
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JACOBSPRODUCTIONS
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The rear brakes appear to have not been working for quite some time, as the wheel cylinders that were replaced were frozen solid. The pads had very little wear on them, as well.
Oct 10, 2008 at 12:30 PM