I tracked down, after working my way through the brake system, that the proportioning valve was not getting any fluid at all on the backside (ports closest to the firewall). Fluid was getting to the proportioning valve from the master cylinder, but nothing was coming out below. I bled the MC properly by doing a bench bleed. I pulled the proportioning valve and leaned it out and pulled out all the internals. Sprayed and cleaned out with brake cleaner. When all put back together the backside ports seem to have a better opening when I blow air thru them. It has not been installed on the truck yet, but I wanted to make sure that the proportioning valve is working properly before reinstalling and bleeding the system. The front ports have mush higher air flow then the back ports... Thoughts?

 

Usually, the front ports do have more fluid flow than the rear ports on a proportioning valve, since there's more braking at the front of a vehicle and it's there to prevent the backs from locking up.

A lot of them will delay fluid to the rear for quad-disk.

Also, it may hold a small amount of pressure to the back for rear-drum since drum brakes expect a small amount of pressure to hold the shoes close to the drums.

I'd put it back in, and see how it runs after you bleed the system.

RwP

 

So I put it back in and bled the entire system properly. Bench bled the MC then bled the lines at each point making sure no air was getting in and then finally bled in proper sequence PR, DR, PF, DF. fluid is to all 4 parts of the vehicle. Jumped in and fired it up pedal still goes to the floor... once in awhile when the truck is running the pedal slightly firms up, but then the next time seconds after releasing the brake pedal the pedal goes back all the way to the floor. Thoughts? Do I have an internal break in the MC? I was thinking maybe the check valve on the brake booster was bad, but everything I have read states that if the booster was bad it would feel as if the brakes were stiff... Any help would be greatly appreciated! Thanks

 

What year is your truck? Do you have RWAL or 4 wheel ABS?

Pedal to the floor means you have air in the system. You may have air in the ABS system in which case you need a DRB (Dodge scan tool).

 

It's the RAWL because the ABS pump is only set up for the rear. How would I properly bleed that part of the system with out the tool?! I live in small town Iowa and don't have any way to get to the DRB tool... Unless a place like oriellys has one... Thoughts? More info is the there was no fluid going into or coming out of the ABS pump prior to me cleaning the proportioning valve...

 

it requires the DRB to properly pulse the solenoids to let the air get out. Basically, there's air behind a spring behind a solenoid, and that is what you are feeling.

I have my opinions about RAWL systems.

 

Any good brake shop should have the tools needed to bleed the system.

 

Ok, I will call a place here in town that might be able to help... So air in the solenoids though doesn't seem like that could be the issue though... Please correct me if I'm wrong, I'm new to the dakota world. But my symptoms is that there is pressure when I apply the brakes every 3-4 pumps, then immediately disappears as if the pressure is gone and the pedal then goes all the way to the floor with no hopes of stopping. I have to then pump slowly again to hopefully come to a stop. Shouldn't I still at least have front brakes even if there is air in the solenoids for the RAWL system?

I agree magnethead these RAWL systems are a pain in the a**... I've heard a few people say they think it's definitely the MC because there is no back pressure going back into the MC since there is an internal leak... I just don't want to throw gobs of money at something like the brake system and not resolve the problem...

 

I unplugged my RWAL from the controller because it would engage for no reason at all, then not engage when I needed it. Since I'm converting to full time race duty, i'm just going to remove the SOB.

 

One more thing - disconnect the vacuum check valve from the booster, and plug it so it's not a massive vacuum leak while running the motor.

For LONG ENOUGH TO TEST THIS ONLY! see if the brakes still go to the ground.

It's very possible that the booster has failed, and it's not properly returning when you release the brakes (due to the fact that the booster applies vacuum to both sides at different times, depending on the relationship between the diaphrams and the brake pedal rod .. )

RwP