Hey ya'all I am fairly new on here! I hang at the Durango and DTR site but need help with my sons 87 D-100,SB,slant banger,2wd with an A-833 trans. I recently replaced the front calipers along with the rubber brake lines bled them and fired the truck up for a test drive and the truck would not move. My red dash brake light was on and my son said the brake pedal moved to the floor as if applying the brakes. Did some checking and the brakes were in deed being applied by them selves. I removed the boost line from the brake booster and then drove the truck but had to stand on the pedal to stop. I realize by doing this I had lost the boost assist but was just verifying a few things. My question is what could be causing this. The boost port where the line goes on the booster has an additional port which I originally had plugged off. I am looking for some ideas here so bring them on. Thanks!!

 

how do the bleeder screws on the rear wheel cylinders look? i think i have read that the proportioning valve can sometimes become unbalanced and cause the brake light to come on. i think you may have to bleed the rear brakes to fix it. did you bleed the passenger side first?

 

Pretty much anytime you do brake work on these, you will need to do a four corner bleed to get it working like it should.

 

I did not do rear brakes but I will consider that into the equation. I believe the actual issue here is with the vacuum line to the hydro booster. Are you familiar with the plastic connector on the booster where the vacuum line from manifold on a /6 is connected. Is that a check valve and can it be replaced with out replacing the complete booster?

 

Power Brake Booster Check Valve.
RAYBESTOS Part # CV89000
http://www.rockauto.com/catalog/more...633&cc=1084430

 

Thanx crazzywolfie for the part number. That is what I need although the one on the truck has two ports. But I have plugged off the non vac hose port. I could not find it on Rock Auto. I did figure out how to navigate the site though. I need to find another valve on the back of the intake manifold. It is plastic and has three ports,for vac hose to the brake booster check valve,cruise control,and vacum to heat/AC I can't find that part because they don't list a manifold,only gaskets. THANX AGAIN!!!

 

that is the only one i saw. i did not see the one for trucks with cruise control. i am not sure what "It is plastic and has three ports,for vac hose to the brake booster check valve,cruise control,and vacum to heat/AC". it almost sounds like you might be talking about the vacuum tree like thing on the back of the intake manifold but it should be metal. not plastic.

 

Crazzywolfie - Yes it is called the vacuum tree and it is made of a pot metal or aluminum. I cleaned it up with brake cleaner and put a small short nail into it with super glue and then covered it with JB weld. I will let it set up before I start the engine. Now as far as the check valve in the brake booster I purchased the part with the number you provided and it is not fitting properly. The valve housing is much smaller than the one that was in there. The two rubber grommets are not fitting properly. The larger grommet fits into the booster housing but it appears I may have to stack them. That may not work other than super gluing the two together. I may give NAPA a call and see what they have. Thanks for your help!!

 

rock auto show a couple universal kits but i don't know if they would work.
DORMAN Part # 80190 Power Brake Check Valve; Chrysler/Ford/GM Application
DORMAN Part # 80189 Check Valve & Grommet Assort.; Fits most Chrysler/Ford/GM Applications

 

Well I ended up getting a check valve from NAPA at much more cost than I paid for the first one. I had to make some mods to the vacuum line in order to get it to fit. I was all excited because I thought this was the problem. I fired the old beast up and the brakes immediately engaged not allowing me to drive it. Sooo back to the drawing board!! I may be looking at a booster replacement but I don't want to just throw parts at it and not solve the issue I have. I wish I could find someone that has had the same issue or find some symptoms or a test procedure indicating the booster has failed. The pedal initially was hard but I contributed that to the truck sitting so long. Any one have thoughts on this???