what’s the part number for the “antilock electronic control unit” for the 1994?

curious if I need to replace my RABS valve on the frame rail at this point.

 

if your truck is an 89, the rabs unit on the frame has no effect on front brakes. it is rear brake control only

 

yes I agree. I just don’t understand where to go from here…..

what is the little plunger looking deal on top of the brake pedal above the brake light switch??

 

cruise control I’m assuming?
whatwver it is there’s no Vaccum on it….?

 

Yes. That is your cruise control vacuum dump valve. It's a safety device in case you have a run-away cruise-control. It dumps the vacuum that the cruise control needs to pull the throttle open. Looks like it's missing a retainer nut.

It won't have any vacuum unless the cruise control is engaged and working.

I don't see any wear on the threads, but it might be slipping down and jamming while you're driving, and causing the brakes to drag.

 

The RABS valve is on the frame, and it cannot affect the front brakes. It can't cause the symptoms you're describing.

 

there is a retainer on it on the bottom side closest to the brake pedal for adjustment. I have a bit of free play in my pedal and I can see that it’s definitely not causing the pedal to bind. Wish it was that easy lol

 

I think you're on the right path. Something is keeping the brake pedal from retracting completely. Broken pedal return spring (my 1994 doesn't have one), broken or stop light switch spring, vacuum dump valve, FOD in the area, etc. This is what my 1994 brake area looks like.

 

I believe the pedal is retracting fully!!!!!! I don’t think I have an issue there whatsoever. Here is why.
it appears nothing is holding the pedal up at all. Nothing in the cab.
In the engine bay, when it comes to the booster push rod and master cylinder, the master cylinder IS DEFINITELY 100% fully retracted. The booster rod is not pushing on the master at all. Even if I remove the master from the booster, I STILL have pressure built up inside the front calipers. I can crack the bleeders on both sides and they will **** and **** and **** until I close them. I still have front wheel drag. If I leave the bleeders open, and turn the wheels by hand (in the air on jack stands) the fluid flow out of the bleeder will pulse with every turn. It never stops flowing out…. Is this just gravity causing the flow of fluid out of the bleeders?? Maybe, but it will empty the master cylinder if I allow it to.
REMEMBER, this is all occurring even with the master cylinder pulled away from the booster push rod. Unbolted. Free and clear, fill cap ON the master, brake pedal out of the equation at this point, yet the brakes are still dragging.

another scenario to consider in this.
I crack the lines at the master cylinder. No fluid flows from master unless I remove the master cylinder fill cap, then it will dribble out. Hook the lines back up, cap the master cylinder, crack the bleeders at the front calipers and they flow fluid out.

 

This is a proportioning valve on the master cylinder is it not??

 

Ok. Let's get some measurement here so we can compare what we're talking about. I jacked up the front wheel on my 1 ton truck and got about 8ft-lbs of sticktion. I tested it with two torque wrenches (maxed out my 1/4" and barely shows on my 1/2" torque wrenches) on the lugnut that gave me the most mechanical advantage. What is your reading?


I also jumped my brake pedal switch to force my stop lights on, and my abs light came on at 14 mph.

 

Funny thing about that... It's not a proportioning valve. It's an adapter. From what I gather, non ABS trucks got proportioning valves in that location. RABS trucks got a straight-throu adapter. The rear brakes get full brake pressure and then it relies on the RABS to keep the rear wheels from locking up. You can tell if it's a proportioning valve or and adapter by looking for a split-line on the body. If it's just one solid body with no split-line, it's an adapter.

 

correct. that is an adapter.
when bleeders are loosened, fluid will drain out until the master is empty. that is gravity bleeding.
something i definitely not rite if you open the bleeders and the brakes still drag.
either wrong rotors, wrong pads, or wrong calipers.
if the master was wrong, when you release the front brake line at the master it would release a spurt of pressuer and the wheels would then turn.

 

This comparison doesn’t help me any. If the truck is cooled off and I do this I get right about the same. 10-20ft-lbs.
if I drive the truck and come back and do this it’s in excess of 50ft-lbs to turn the wheels and the brakes are smoking hot from dragging.
For reference, if I drive further than 2-3 miles, it gets excessively worse. If I get up to 55 mph, I really gotta lay into the throttle to get to 60. And by that time the rotors are flame orange and are gonna destroy the dust boots on my brand new calipers. Not gonna do it u til I remedy this problem.

It appears that I have a straight through adapter then, not a proportioning valve.

 

Closer to 20. Can’t seem to find my 3/8’s to 1/2” adapter to try with my 3/8 torque wrench