Can't figure out what happened. Was woking on the Mrs's daily beater (98 Grand Cherokee) and decided I'd had enough of the caliper problem Jeep knew but would never admit was crap.

Installed new calipers (front only) with steel pistons instead of OEM Plastic.

Took brake line off of calipers, then took calipers to the parts place for the swap to avoid core charge. When we got back, the master cylinder reservoir was empty with brake fluid all over the floor from the loose lines despite tying them up and wrapping tape around them.

Attached new capipers and brake lines, filled up the resevoir and started the nasty process of two man bleeding. (push/open/close/release) RR, LR, RF, LF. Went through almost a 1/2 gallon of fluid - no bubbles could be seen.

Good pedal feel UNTIL it was started and the power brakes kicked in. Push, and pedal went almost to the floor. Went for a drive to bed the new pads and they would start to grab about 1/2 pedal, but pedal continued almost all the way to the floor before HEAVY braking kicked in. (could not stop hard enough to get the ABS to kick in)

Came back, repeated entire process - another two quart bottles of brake fluid, RR, LR, RF, LF - No air anywhere! Result? Same damn thing.

The car has ABS system, but no lights came on. Doing a normal slow speed stop, about 1/2 pedal will do OK, but feels spongy - WHile sitting stopped - continue pushing on the pedal and a "whoosh" sound is heard while adding more pressure to the pedal, and the pedal going almost to the floor.

WHAT HAPPENED - - HOW TO FIX? It's the wife's car and she is livid!

Need help or will need to rent a room at your house

 

Sorry, I don't have the answer to your problem. If the wife gives you too much crap just tell her they're fixed when they're not. More than one way to get even

 

Your master cylinder might be toast. It's not giving a good seal where it usually works. It's not until it gets to an area that has not had much use that it seals properly and applies the pressure. My .02

 

bleeding the ABS part of the brake system can be tricky. I had a similar problem years ago with my Dodge Grand Caravan. Ended up taking it to a brake shop; they bled it themselves (apparently the "correct" way)... and it worked fine after that.

 

Possibly the ABS unit bled out and there is a massive amount of air in the line. Typically takes the dealer tech to bleed an ABS unit.

Another possibility is that you installed the calipers on the wrong sides and the bleed plugs ended up on the bottom. The air gets trapped in the top of the caliper not allowing you to bleed the system completely.

 

It was working just fine before - was just doing what I'd done about every 10,000 miles - replacing front pads, EXCEPT the resivoir went very near dry while away.

Did not push brake pedal or anything until the resivior was filled up again.

Letmeee get a pic of it up - maybe that would help.

 

if the ABS solenoids on a Jeep are similar to those use on a Corvette or other vehicle with similar ABS units, after doing a manual bleed (either vacuum or pressure), an automated bleed procedure must be performed.
During the automated bleed procedure, the ABS solenoids are exercised, allowing trapped air to be replaced with fluid. These solenoids are not activated during a normal bleed procedure.
Since you state all the fluid bled out of the master cylinder, there is probably cause to believe you have air in your ABS solenoid assembly.
With GM products, a Tech 2 is required to exercise (open/close) the solenoids, a similar tool will probably be required on a Jeep.

 

Here's what the master cylinder and ABS unit look like. From the Master Cyl, there are two lines that run into the ABS unit. Then there are 3 lines running out of bottom part of that. Unable yet to trace where they all go.

Patches - Already check that! They are on correctly - Great tip though - one I almost missed!

Don't fricking tell me I got to take it to Jeep. I will have to resupply myself with a large jar of vaseline and lipstick to ease the experience.

 

Two lines from the master cylinder to the ABS valve unit, then three lines from the ABS unit; one for each front wheel brake caliber, the third line goes to both rear brake assemblies. (A three circuit system, which allows the ABS to pump each front brake separately, but the rears together; quite common on trucks a few years ago. The Vette and most cars today use a four circuit system, to allow the ABS system to control each brake assembly separately.)
Again, not familiar with the ABS unit used, but if similar to the ABS on a vette, the secondary circuits within the unit require the solenoids and motor to run, to bleed out the air.
Normally, breaking any of the brake lines from the master cylinder to the ABS unit, allows air to enter the lines requiring the motor and solenoids to be exercised to bleed properly. The master cylinder completely draining itself of fluid allowed air to enter the lines above the ABS unit just like breaking open one of the lines.

The reason you had great pedal feel until you started the car also makes me believe it is air in the solenoid assembly, and now into the lines. All ABS systems go through an initialization process when you start the car. In this initialization process, the ABS motor is turned on, and the solenoids are exercised, and when this happens, air is entered into the primary lines of the brake system.

I guess it would be possible to manually bleed the system, then start the car to initialize the ABS system, the bleed again, etc., until all the air is out of the system. However, this could take quite a while and the cost of brake fluid would be high. You would also never be sure you removed all the air.

IB4TL....but good luck. Call a reputable brake shop of the dealer. Again, I'm not familiar with what ABS system is used on a Jeep, my wrangler has no ABS.