88bird

i have a 96 3500 RWAL and here's my prob.... i went to get new pads on the front and get the rotors turned and all went well till i went to pump up the brakes..... it pumped up well nice firm petal when the truck was off...... cranked it up, let her idle for a bit and pushed on the brakes and they went slam to the floor...... pump the brakes they build up and then go to the floor..... replaced the master cyl.... bench bled it and did the exact same thing...... got another from different parts house....... same thing.....replaced front and rear proportional valves...... samething build up after 5 or 6 pumps and then straight to the floor....... bled out the whole system countless times..... bypassed the booster still the same thing...... please help me i'm starting to go greyheaded and i'm not even thirty yet......

infidel

Sounds like the abs unit has air in it. The bleeding procedure is far more typing than I want to do here, suggest you look at a manual.

88bird

it has no abs pump..... no abs relay... there is a spot for it but no pins to plug it into..... or anything like that.......... all it has are 2 solonoids on the rear proportional valve..... it has an abs light but no relay for for that either, no pins to plug up too and there is a spot for an abs fuse but no fuse and no connector for that..... please help..... i can't stand to see my baby sit any longer.....

88bird

anyone have any ideas ....... ever ran across this problem?.......

infidel

Sounds like a leak the way the pedal drops off after pumping.
Fluid level staying up?
Have the calipers been removed and are maybe upside down?

88bird

the front calipers were just unbolted to remove the rotors and install pads... fliud level stays the same.... there are no visable leaks on the concrete floor it's been parked on for the last 2 weeks.... none of the fittings are wet or anything.... completely flushed the whole system.... i bled about 3 quarts of fluid through it was all clear lookin.....no air bubbles or anything

88bird

well after some new calipers and another master cyl.... i finally figured it out..... if you ever go to autozone and get wheel bearings and your truck is 8 lug and rear abs w/ the 10500 lbs gvw and the big rear axle DON"T get the set 11 Timkin bearing it calls for..... get the 15101 timkin i believe it is..... the set 11 isn't the correct size and my "help" didn't look at the old ones when he installed them.... the center is bigger than the 15101 .... it kicks the rotor in and allows the wheel to have ALOT of neg. camber and causes the caliper to bind and bupass the fluid somehow...... so if anyone rins into this this might be your problem.....

infidel

Yep, a problem from a wrong part is one of the toughest to diagnose. That's the reason many professional mechanics hate working on a rig that someone else has worked on and failed, too many "unnatural" variables involved.

Hemi Cat

I second that!!!!

bmoeller

Preachin' to the chior. My boss' little brother is bad about that.

infidel

It's like this old one-

Service Charges:
Labor Rate Per Hour $35.
If you Wait $40.
If you Watch $45.
If you Help $55.
If you Worked on it Yourself $65.