99 4x4 brake issues

[Kentw]

My rear drum brakes don't seem to work. I have replaced the shoes, springs, cylinders (old ones were leaking), and bled them. The drums seem ok and are not at the max diameter. I manually adjusted them with the truck on jack stands. I started the truck, put in gear (still on jack stands) and press the brake. Tapping the brake will not stop the back wheels. I have to press it very hard and the back wheels will eventually stop. This doesn't seem right and on the road it doesn't seem to stop very well either.

It has plenty of fluid and the proportioner valve appears to work as the plunger protrudes when the pedal is pressed.

Also the dash BRAKE light will be off but come on after about 5-10 minutes of driving the truck while it's going, not while the brakes are pressed. It will then stay on until the truck is turned off. The next time it will be off until after about 5-10 minutes of driving.

By the way, it has RWAL.

Any ideas?

[hot64goat]

Dodge pickups are haveing a problem with the brake sensor going bad that is why your light is comeing on! Mine included. It is $33.00 from the dealer and located above the ring gear on the differential. The best way to test your brakes is do a panic stop on gravel then get out and look for 4 skid marks. I have done it in a parking lot also in extreme cases.

[Kentw]

Thanks, but I recently replaced that already because the speedometer didn't work until about 40MPH and the brake light was on all the time. The spedo now works fine so I assume that sensor to be working fine. Any other ideas?

[hot64goat]

What kind of pedal do you have is it soft or mushey? or rock hard? if it's hard and slow moving it could be a booster or a vacuume leak to the booster. Did the master cylinder ever run dry? They may need bleeding if it did. The only other thing left would be a master cylinder

[RICHARD312]

improper install in rear. Did light problem begin after a brake job?

[Kentw]

To answer questions from both hot64goat and RICHARD312:

The pedal is very firm and barely moves with the truck off and is firm with the truck running which appears to be normal. I have only had the truck for two months and as far as I know the master cylinder was not run dry.

As for the dash BRAKE light, it was on constantly when I first bought the truck and the spedo didn't work under 40 MPH. I replaced the rear diff sensor and the light would come on a shortly after the truck was started and stays on. Later I knoticed the rear cylinders were leaking and replaced them and bled them. After that the light comes on after about 5-10 minutes of driving. So the brake light problem has been there from the start but is getting better.

[pind]

buy some 30mm gm wheel cylinders from napa, the part # will include the numbers 37337 possibly with a prefix. give the napa guys that number, and they can work with it. these will greatly improve how the rear drum brakes on your truck work.