William Kisselstein

Van was fine Sunday and I let it sit and Friday night I get in and go to leave and pedal is really low, and does not come up. I drive and make a couple stops and it gets worse, brake light comes on.

So I check the reservior. Front just about dry, back about to follow suite.

Okay but where did it go? No puddles, no wet down a tire, no wet spots on the frame, nothing.

I put two small containers in which fill it just to overflowing because the left side front is slightly low where I had parked. Snap top on carefully, pump, brakes come up, hard, no loss of pedal. Drive four miles, let sit four hours, drive four miles home. Brakes are fine.

What is going on? Where did the fluid go? You don't dump two small bottles worth and not leave some kind of puddle somewhere. But I can't find one. I have yet to look at what routing the lines use for the ABS, I had a 95 G30 and it wasn't worth replacing the lines on to go to the ABS unit under middle right side of the van and then to the wheels.


... one of my G20s the rear hose fitting, where the two lines to the wheel cylinders screwed in, once cracked. It would vent fluid under hard braking but otherwise was normal, and other than the reservoir needing refill no clue there was a problem. Would not do it when parked. Can only guess I have some similar issue. if it was leaking past the seals in the rear wheel cylinders I would see it. Front right has good pads. Front left should also, never did get that wheel off.

SteveROntario

Lost a brake pad?

dberladyn

It's just squirting out somewhere I imagine. Mine did that. The steel line developed a leak from rubbing against the fuel filler tube. On my build it was a factory defect, and a subsequent recall. Only I never got to the problem before I partially lost my brakes.

joelsplace

I didn't see where you told us what the vehicle is. If it has a vacuum brake booster is can suck fluid in if the rear seal in the master cylinder is leaking and the booster is leaking. The brake booster can hold a lot of fluid but normally quits working in that situation.
The pedal not returning is a bad sign for the master cylinder. The spring inside should return the pedal even is there is no fluid.
If it is a hydraulic power assist then it should leak out between the master cylinder and booster.

William Kisselstein

The pedal always returned. No signs of leaks around the master.

First one in my signature, 2002 2500. Has hydroboost.

I finally got a chance and changed the left rotor, which had a slight warp in it, and put fresh pads on to match the right side.

About the only change in it is it's now grabby in the front, particularly the left - but it was a little grabby there before, just less noticeable because the rotor was rough and one pad was worn way down.. I'd chalked the grab up to the warp.

So it must have air in the lines to the rear and maybe right front too. I did finally get a scraping noise from the rear that makes me wonder if the shoes are worn but haven't had a chance to look. The last time I had to take these drums off, I had to drill a hole in the right rear backing plate so I could use a screwdriver to hold the adjuster or the tool would just pop out of it. Pain in the behind. But if they were really worn then fluid could escape from the wheel cylinders each time I stop, but maybe not enough to leak out the drum.

joelsplace

"does not come up"
I thought that meant the pedal didn't return but I see you meant it went down too far.
Rear wheel cylinders won't leak from worn shoes unless the are so far gone the pistons fall out. You need to check the wheel cylinders if you haven't. Pull the boots back to see if they are dry under them. If they are wet replace them. Fix the adjuster while you are in there.
Shoes adjusted too loose will cause a low pedal.
Grabby brakes are usually from fluid, oil or grease contaminated shoes.
A rear brake can feel like a front. You can find out which one is grabby on gravel.
Air in the system can't make one wheel grab. The pressure equalizes right to left but not front to rear so air can cause low pedal and one end to not work.

William Kisselstein

Could hear the tire chirp when it grabbed. New, clean pads, entirely different rotor, same problem. Only issues on the old set were the ring of rust around the inside of the rotor and the slight warp causing vibration at speed.

Have had cars do this before, in fact when I had that cracked brake hose fitting you could feel that van grab in the front with little or no action in the back.

Air in the system compresses differently and if there's a bubble in the line to the right front then the left is going to apply first and pull a little.

Clearly it needs to be bled out, but I don't believe I can do that myself.

Parran

If you get a bleed kit, you can bleed the brakes alone. They are readily available in any parts store.

William Kisselstein

It's never that easy, those one-man kits I usually toss the little bottle aside and run the tube into a big bottle of fluid. But you have to get it flowing somehow. A pre-ABS van has little to slow it down. The '95 with 4 wheel ABS the lines ran to this unit under the van, then to the wheels, someone had already plumbed out the rear lines when I got it. These 2002s I honestly have never looked at how the lines run or where the ABS unit is, but I presume a similar spaghetti plate of tubing. Well maybe not that bad but I read lots of stories of guys who try to bleed these and can't get the fluid to move.