No rear brakes!

I am having a tough time figuring this out. I have a 97 XJ, 4.0, auto, no abs. I just bought this XJ a couple months ago and during a recent snowstorm I found out that only the front brakes are working. I thought the adjusters weren't working so I replaced the adjusting hardware and shoes on both sides. I adjusted the shoes up to the point they would drag then backed off a couple clicks. Test drive proved that wasn't the problem. I then bled the brakes and still only the front work. My question is can half the master cylinder not work? How often does a proportioning valve fail?
Any help would be appreciated before I slide into semi trailer again!
Thanks, Dave

When you tried to bleed the brakes in the back, they must not have squirted out, right? Loosen the lines coming out of the master and see if they both squirt fluid.

winterbeater said:

When you tried to bleed the brakes in the back, they must not have squirted out, right? Loosen the lines coming out of the master and see if they both squirt fluid.

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x2, are you getting fluid at the rear with good pressure?

The proportioning valves are not "serviceable", meaning you can't buy parts for them, but you can disassemble them and clean them, fairly simple but there are springs under pressure in there.

Did you set the parking brake tension? The way it's designed, the parking brake gets the pads in place and the adjusters keep them there.

Simple test for this actually: When driving down a clear stretch of road, pull the parking brake about halfway and then press the pedal. If you feel a BIG difference in the rear brakes then the preload is out of whack.

ehall said:

Did you set the parking brake tension? The way it's designed, the parking brake gets the pads in place and the adjusters keep them there.

Simple test for this actually: When driving down a clear stretch of road, pull the parking brake about halfway and then press the pedal. If you feel a BIG difference in the rear brakes then the preload is out of whack.

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Hey, I think we have a winner! My park brake barely works all the way up! Do I just need to adjust the cable under the vehicle?

You need to look at the pistons themselves (wheel cylinders). They may be stuck/frozen.

yeah adjust the cable until the wheels barely turn then loosen a bit, just like the adjusters

ehall said:

yeah adjust the cable until the wheels barely turn then loosen a bit, just like the adjusters

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Assuming the adjustment is good in the drums then pull the e-brake up 3-4 clicks I think it was (on jack stands in netural) and adjust the cable (inboard left frame rail back by the rear wheel) until you can't turn the wheels.

yeah pull the handle about 1/3rd first sorry