Proportioning valve stuck

To my knowledge, the porportioning valve can't be bled using the ABS bleed feature of a scan tool and has to be manually bled.

The brakes will need to be bled normally, and GM has a depressor tool specifically made to be installed on the valve while bleeding the brakes: J-39177.

You'll have to bleed the front and rear brakes as normal, but with the tool installed in order to remove the air trapped in the valve.

master cylinder have 3 sections. front, back and proportion valve.The valve control the pressure to the rear brakes.Start bleding from the master cylinder. if the pressure is good inspect the line for damage.if one line don;t have pressure replace master cylinder
Good luck

check for fluid before and after the proportioning valve by disconnection the line after the valve and applying the brakes, if no fluid after valve try before valve if fluid is there then it is a bad proportioning valve. you did bleed the master cylinder before connecting the brake line and trying to bleed the brakes all at once right? If the master cylinder was not bled first then a lot of air may have been forced into the rest of the brake lines.

sometimes you can tap on the proportioning valve while someone pumps the brake if nothing breaks loose you may have to replace the valve.

bleed master cyl ,abs, and check proportioning valve, proportioning valve if stuck will stop flow to back etc

The problem is probably that you must do the lr before moving to the front. The air in the lr will make it too spongy to bleed the front.
A wheel cylinder is only $25, so you might as well just replace it. And if you use vasoline or brake lube on the bleeder, it will not rust up on you next time.

Proportioning valves are not supposed to block a bleed. They can malfunction, but should not supposed to. And if you have the back working, that should reset the proportioning valve anyway. You can't leave the back. It must be finished.

What happens when you try to bleed the rear brakes? If nothing comes out, trace each line back toward the proportioning valve--something would be blocking flow of fluid. Disconnect each line at the forward end and see if fluid comes out of the valve openings. You will need a scan tool to complete the bleeding process with ABS. Suggest buying a Chilton's manual for this truck because of the complexity of the ABS system.

should not need to bleed module try giving the proportion valve afew good smacks sometimes this will dislodge the valve then rebleed

How did you come to the conclusion that the master cylinder is ok? Does the level of brake fluid in the MCyl. rise & fall while pumping the brakes. I feel no fluid is entering the chamber which has the piston. This piston is directly connected with the brake pedal.Have it checked and the oil seal in it too.....sodeep

the stratus is know for clasped rear brake hoses .This stops the flow off brake fluid. try opening the brake lines at the master cylinder that go to the rear.pump up brakes first! if you got fluid than check the brake line if this is rear disc brakes on the line at the rear will be a built in proportioning valve.if drum loosen rubber hose line before the rubber part to see if you have fluid. If you do replace the brake hose! On you 74 challenger by the way i love dodge! any way on the valve there is a small button on the front of the proportioning valve that pops out it needs to be tap in lightly. also hit the brake peddel kind of hard a couple off times if that doesn't work. thanks for your question


p.s that hex bar on the is a junction not a proportioning valve .