When I bought my '93 the PO had installed a new master cylinder because the brakes were soft. The new MC didn't fix it though. It stops good, but the pedal is soft and almost goes to the floor. On the second pump, the pedal is rock hard. I have bled the brakes and adjusted the rear brakes.

Any Ideas?

 

Willing to bet it's your ABS valve on the rear messing everything up

 

Adjust the rears up a little and see if the peddle improves.

 

Mine was doing that. the valve was stuck open in the rwal, and I needed a couple push of the pedal to fill the rwal valve, then it braked good.
I bypassed that, but one day I'll take it apart and try to get it working again. In show it is better with rwal working.

Have someone pumping the brakes just after shutting the engine off (to have some vacuum left) while you listen very closely to the rwal valve. If you hear some noise in there instead of inside the brake drums, bypass that module.

 

I agree with adjust the rear brakes as a first step.

 

My ABS and brake warning light stay on all the time except when the brake lights are on. Something is haywire in the wiring because the brake lights won't work with the stock switch.

I have a power wire coming from the fuse box to a 2 prong Chevy brake light and a wire from the switch to the white wire on the stock switch harness. I tried a new brake light switch and it didn't work.

My speedometer and cruise don't work either. Do I have PCM troubles?

My anti lock brakes don't work. I can easily lock the rears up on gravel.

 

He says in the 1st post he adjusted the rear brakes. you can adjust the rear brakes so they're dragging like i did and rear brakes still won't work on the 1st pump if that valve is bad.

Buy a new valve from rockauto or bypass if you don't think you need ABS, You just need a short piece of brake line to hook the inlet/outlet together, the outlet on the RWAL valve has a bigger fitting though so you'll need an adapter or a short piece of line with 2 different fittings on each end

 

Does the ABS light come on if the valve is bad? I would like to have the anti lock brakes work (along with the stock brake light switch, cruise, and speedometer). I will try a new valve.

 

Will the valve off of a '89 work?

 

I'm amazed at how many of us post threads about bad brakes. There must be hundreds of them to read through... and unfortunately, it's always about the same thing.

Realty is, that I had the exact same problem as you and every other guy here that posted issues about mushy brakes. I went through the system, replacing master, booster, wheel cylinders, calipers and lines, and still... mushy brakes.


It wasn't until I found this thread, that I realized that I .... not the truck.. was causing the mushy brakes by not properly bleeding the system with the proper tools. For some stupid reason, these trucks need to have a container filled with brake fluid @ the rear wheel cylinders, to be able to bleed them correctly.


https://www.dieseltruckresource.com/...68&postcount=2


Here's my thread where I discovered that it was me doing the truck it's injustice

https://www.dieseltruckresource.com/...+dodges+normal

Pay particular attention to post # 11

https://www.dieseltruckresource.com/...8&postcount=11

 

My 93 has been doing the same thing as the OP stated. I have all new brakes. And my shoes are adjusted tight. When you first apply the brakes the pedal is mushy. After you apply them again they are better. I just tried the bleeding procedure with the bottle and hose. I didn't notice any difference. I'm guessing it is the RWAL valve. I attemped to bypass it, but it looks like the brake lines are wanting to twist off. Even after I've soaked them in PB blaster.

 

[QUOTE=1972RedNeck;3114471]Does the ABS light come on if the valve is bad? I would like to have the anti lock brakes work (along with the stock brake light switch, cruise, and speedometer). I will try a new valve.[/QUOTE

The valve can be bad and not set a code or turn on light. Usually the brake pedal will fade slightly under braking then seem normal after braking. The valve is stuck and dumping pressure, replace the valve.

 

Update

I just bypassed the valve when I swapped my axles out. I bled it like normal, and now I have the best brakes of any of my vehicles.

 

anybody have a part number for that valve? or a link or somethin?

 

still might be the master cylinder. Your bleeding off the so you pump the system up on the first then the second you have brakes.

If you you pump it does it slowly bleed to the floor?