2nd Gen Non-Engine/Transmission Help please!! 98.5 drw rear brake emergency

[CDenton]

In need of some help with figuring this out. Here's what i got going on. Truck gets drove around town alot, quite a bit of stop and go traffic. After a while the brake pedal gets really sensitive and when i apply the brake a decent amount the rear duals will lock up. Sometimes I can feel the abs pumping the pedal and then sometimes I cannot. Also truck feels like the rear end is trying to pass the front. Recently put it on the scanner to read the abs. it told me the rear abs sensor, im assuming it was the one in the rear dif, was not reading anything. So today the new sensor came in and i swapped the new and the old. Figured while i was working on the truck to go ahead and check out the rear brakes. everything inside is looking good all springs adjustments and so on. The drums look good measured them out and the shoes are good as well. So slapped everything back on and took 'er for a drive. Brakes are working a little bit better figured due to the fact i cleaned them up a little. problem still remains though rear brakes lock up somethings still not right.



Any ideas? master cylinder? Hydro boost?



Thanks ya'll

 

[JR]

Does your truck have the rear load sensing proportional valve? (I think it should). I would unhook the rod and play around with the valve, I think if you turn it counter clockwise it will decrease brake pressure. If it is an abs related issue you should be able to pull the fuse and see whether it corrects your problem or not.

 

[CDenton]

where is that located? on frame or on the axle? could you describe it for me

 

[BDaugherty]

replace the wheel cylinders and bleed the whole brake system including cycling the abs. also make sure your new senor is reading.

 

[Road Dog]

Dad had that with a Chrysler Newport. The brake booster was basically full on/full off. Another thought is a collapsed rubber brake line. It can act like a check valve and not release the brake pressure. The abs sensor generates pulses so if the wheels aren't turning there's nothing to read.

 

[JR]

where is that located? on frame or on the axle? could you describe it for me

It is mounted on the left rear frame rail above the rear axle. It will have a long arm connecting the axle to a proportioning valve. The more weight in your bed, the more brake bias is put to the rear brakes. Usually the symptoms of a bad proportional valve are poor rear brakes, but it won't cost you anything but 5 minutes to disconnect the rod and play with it a little to see if it helps or not. It does seem like either more of a booster or abs issue, but I like to eliminate the simple things first.

 

[budnate]

you might try a entire spring and hardware kit as well..... on another thread a guy was having issues and finally changed his out and cured him... . I recently was having issues like this my shoes were getting a tad warm and real grabby... . and smoked one side on a long run down the road, went back into the brakes out back and changed out the kit and all is good again... . anyway not much money and you check that off as a possible problem... . I would also do your wheel cyls and flush the brake fluid front to back .