Just so you guys know, I had this work done at school and I was also working on my truck.

Here's the problem. I had new calipers installed because the old ones were sticking. No problem so I thought. Installed the calipers, new pads, and turned the rotors. Bled the front brakes, and i was all set, or so i thought. Drive the truck out of garage, park it, go to class and every things cool. I come out about 3 hours later, and I have almost no breaking power. At all. the pedal goes right to the floor. It's all the drums working, and they aren't doing a very good job either. if I pump the pedal, the pressure builds up enough to stop from about 20 mph, but any faster than that, and it takes 6 miles to stop. I have to pump the pedal to stop the truck.
Anyway, we brought the truck back into the garage, and the instructor played around with it, and he thinks it the Proportioning Valve coming off the master cylinder. He played with it for awhile, and the braking got a little better but after driving around the parking lot for a little bit I have no breaks again. All the power is being lost.

So far, we have no idea what is going on. the master cylinder is good, it is pushing fluid through the system. And the break booster is working fine as well. We think it's the proportioning valve.

Couple questions.
Do you guys think it could be that valve?
Where can i get one? Advance, Napa, and rock auto all do not carry them.
Any other ideas as to what it could be?

Thanks guys.

 

soft mushy pedal that pumps up, usually indicates air in the lines.
it was working fine before you started, right ? that makes me doubt the prop. valve.
no leaks right ?

i'd manually adjust the rears up snug, then rebleed the brakes, starting with the rears and ending with the fronts. if that doesn't work, i'd guess the seals in the master cylinder are shot, and replace it.

the prop. valve's job is to even out the pressure between front and rear, trying not to let one lock up before the other. i've replaced a lot of brakes but never a prop. valve. also, since autozone, advance, and napa don't carry it, then its not a common replacement item, and i don't think that's whats wrong. i'm thinking your instructor is just guessing....

master cylinders will always move fluid when you open a bleeder valve. the real test is when the bleeder is closed, and it has to hold pressure. thats when the pressure overloads the seals.

 

dhvaughanis right.

Pull the wheels, look at the brakes, no leaks then you just need to bleed.
Passenger rear, driver rear, passenger front, driver front. NEVER let the master cylinder go dry or you have to start again.

Jeff
Just an old guy with a car hobby.

 

Yeah, I would doubt it is the proportioning valve if it worked fine before. You did not mention if there were any leaks, if so then I would check your connections and lines, then go back and bleed all 4 tires.

 

Yeah it sounds like you have air in the lines to me too. I'd keep bleeding them. You should start with the tire farthest away from the master cylinder and work your way from there until all are bled.

 

since your bleeding the brakes and you did a brake job and didnt ajust the rear, shame shame,there is a mod u could do for the rear i havent done it yet but when it time for brakes im gonna.ok you could change the rear wheel cylinders to a 3500 series insteed of the 1500.i seen it in here maybe diy but i forget but there was many lookers and likers then doers so give it a shot.oh and about your brake it air its got to be you drove it there remember.

 

I didn't bleed the rears because according to Alldata the system the system is split front and rear, not front,rear/ front,rear.

As for the rear bleeder valves, I highly doubt I will be able to loosen them without snapping them off. Can i get new bleeder valves for them?

As for the leaks, there are none, and I know there is air in the system. The problem is it's not coming out. We sat there bleeding the brakes for a good hour and we got nothing but fluid. The master cylinder was working just fine, as was the entire braking system except for the calipers which were sticking. The rear brakes were working after this problem started which leads me to believe the master cylinder is working. It's still pushing fluid back there. Enough to make them lock up real quick even.

Can someone give me the proper Chrysler specified way of bleeding this system? I think one of the other students that was bleeding the system the first time did it wrong.
The system will hold pressure, but not for long.
All the line connections are tight.

And lastly, my truck has 2 wheel ABS. Is that a rear or front system?

Thanks for the help guys. I really miss my truck and i want it back soon.

 

I will say I bled and bled my brakes before I got them to feel exactly right. I thought I had it right and they worked okay but the pedal just didn't feel quite like I wanted it to. It seemed softer even though others that drove it thought it was normal and it stopped fine I decided to play with it and bleed it a little more. I finally got it back like I had it before but it took quite a bit of bleeding. I never had it like yours but it really just sounds like air in there to me. I'd bleed the brakes some more.

 

Sorry double post. Please delete this.

 

spray the rear wheel cylinder bleed screws with wd40 or pb-blaster. use a goodsocket that fits to crack them loose for the first time. then use a regular little wrench for bleeding. if they break off, the best next move is to just replace the wheel cylinders. they are not too expensive $10-15

your 2wh abs is rear-abs.

my guess on what happened is that the students bleeding your breaks let it run out of fluid, and introduced air into the rears.

just give it a good thorough bleed/flush, and it will probably be alright. tip.. this happened to me on my son's hydraulic clutch. i replaced clutch master cyl and slave cyl, filled up master and began bleeding at slave. i bled and bled and bled by just cracking open the slave, while son pushed pedal. fluid would sort of ooze out, but not all the air would come out. it would pump up and get a stiff pedal, but i couldn't get a stiff pedal on just one push. so finally, i just unscrew the bleeder several rounds instead of cracking it, and told son to do one big push and hold. by doing this, it squirted air like crazy, when it would not come out before. idk - some kind of air lock.