Greetings, fellow Dakota friends. Name is M.J., and I'm having the strangest brake problem with my '96 Dakota 4WD V8 Club Cab 1st Gen. And yes, before you ask, I've scoured the site, performed searches, and read all the FAQs. I've found similar threads, but no answers. So, here goes ...

I replaced the RF caliper, as the original one was starting to seize. I have done this too many times to count on other trucks (I also have a '95 F150 2WD). "No problem," I think. clamp the hose, remove the caliper, swap on the new one, reconnect the banjo bolt, unclamp the hose, and bleed. Easy, right?

WRONG!

Using a buddy at the bleeder screw, I did what I've always done: ignition off, pump the brake pedal 3-4 times until hard, have buddy open the bleeder, let the pedal fall to the floor, close the bleeder, let off the pedal and let it rise. Repeat 3-4 more times until clear fluid (no bubbles) are coming out. This whole time, we're checking the master cylinder reservoir, making sure it never went dry.

So ... everything seems just dandy. Start the engine and ... pedal falls to the floor! Turn the engine off, and I pump the brakes, exhausting the vacuum reserve. No problem. Just to be sure, we re-bleed ALL the bleeders, RR-LR-RF-LF -- NO AIR coming from any of the bleeders. Each time, after 3-4 pumps (engine off), the brake pedal builds a nice firmness. Okay ... so all the air is out of the system -- right?

Crank the engine again and, lo and behold, the d### pedal goes right to the floor AGAIN! However, THE MASTER CYLINDER FLUID LEVEL HAS NOT CHANGED. I am COMPLETELY flummoxed, now. I've never had this happen. Could it be the rear ABS block? The combination valve? I have no idea ... HELP!

Again, the steps I've gone over:

1. Removed and replaced RF disc brake caliper.
2. With engine OFF, perform pedal-pump bleed at new RF caliper.
3. Start engine, pedal goes to floor.
4. With engine OFF, perform FULL pedal-pump bleed: RR-LR-RF-LF -- NO AIR FROM ANY BLEEDER.
5. Start engine, pedal goes to floor -- master cylinder still COMPLETELY FULL OF FLUID.

I should note that I did have to move the truck 10 ft. or so, out of my buddy's garage. Moving very slowly, I could still stop the truck -- in both reverse and drive -- but the pedal is completely on the floor and both the ABS and BRAKE instrument panel lamps are illuminated. Parked it, for now, as I have no idea what to do.

My hunch is the ABS/Proportioning/Combination valve, but I've never had this problem on my F150, which has a similar rear-ABS type proportioning valve system (never had to bleed it).

ANY help would be greatly appreciated, as this is my daily driver. I love this truck -- almost 300K on it, and she still starts up on the first key turn, and she loves to 4WD and rides great! I'm so bummed about this brake pedal thing, and am at my wits end! I've done so many brake jobs, before, but just can't figure this one out.

Again, thanks for the help, and the patience with a forum n00b.

Sevenscence AKA "M.J."

 

Brakes actuate as soon as vacuum is pulled?

Try pulling the vacuum plug off the booster, covering it to avoid the massive vacuum leak that can cause, and ... see if that takes care of the "goes to the floor".

Sounds like your booster's failed on the counterpoise side, and therefore the vacuum sucks it right down.

There's also a chance that the master cylinder itself is now blown from being overstroked on the bleeding - I'd look hard at doing booster and master at the same time.

After that, I use a vacuum bleeder instead of the assistant ... specifically, since it's just me and my truck, my car, the stepson's truck and car, and nothing else we're doing brakes for, we use this unit from Harbor Freight. There's others, and it's nowhere near pro grade (as in works for thousands of bleeds - I'm having to replace it after only four years and eight brake jobs.)

RwP

 

I know I’m a tad late to the party but did you ever get this problem figured out? I’ve got a 96 4x4 club cab and I’m having the same issue