I tried doing some research but it seems no one has had a similar issue. I recently replaced the brake lines and brake master cylinder on my 2000 Disco 2. Previously, the brake pedal traveled nearly to the floor in order to get it to stop. After bleeding the brakes (done all methods via abs modulator/power bleed activation and pumping the brake pedal) the pedal still drops to the floor on the first press, then eventually build pressure. Wait 30 sec and the pedal will drop to the floor again. With the engine running, it takes about 10 pumps to build pressure.

I replaced the master cylinder again thinking I got a bad brand new part. Bled the system again about 10 times now. There is absolutely no air coming out to the lines. We even bled the lines at the master cylinder and the abs module. I'm still in the same situation.

Anyone have a similar issue or any ideas. I'd really like to be able to drive my truck again.

 

Have you tried pumping the brakes and cracking the lines loose at the master cylinder?
Sometimes you get air up in the lines and it will keep rising back to the top. I've had this happen on my motorcycles a lot. But it happened on my GMC truck also.

 

Unfortunately that's been done about 12 times now. No improvements.

 

Nobody installed any calipers with the bleeder screws on the bottom or anything? That can cause problems like that! If not you could try gravity bleeding them for ten or fifteen minutes on each caliper. Then bleed them again. Just make sure the reservoir is full.


Sometimes if you have air trapped in the system you just have to open up the bleeder screws one at a time and pump the hell out of the pedal. That's what I usually do if it's difficult to get pressure. There's got to be air trapped somewhere if the pedal is sinking like that with a brand new master cylinder and no fluid leaks. When normal bleeding fails, sometimes it's the only way to get the system working again.

 

I hate to admit it but my friend and I have tried all of that. We even made a power bleeder from the braking system from a old BMW power bleeder. This is by far the craziest thing we've ever encountered.

 

Does fluid shoot out of the bleeders when you pump the brakes? Or does only a little come out? Or does nothing come out?
Whatever it's doing, I would take a clear bottle or jar and put some brake fluid in it. Make sure it's enough to keep the end of a tube submerged. Probably two or three inches deep. Then open a bleeder and put a tube from the bleeder screw, down into the fluid. Then, making sure the end of the tube is submerged, pump the brakes and watch to see if it pushes out fluid or air bubbles. If it's pumping out air, just keep pumping until no more bubbles come out. This way it will only suck up fluid when you release the brake pedal.

 

It comes out at a decent rate when pumping the brakes with the bleeder open.

 

Okay, try putting a tube down into a bottle of brake fluid and pump the brakes. There may only be a little air escaping at a time. This way there's no way for it to suck up air and the fluid will hold the air with a little bit of vacuum, so it will keep heading out of the lines. Be sure to do all four thoroughly.

 

We did that too. A local Rover shop suggested that's the best method for bleeding the brakes. Still have the same issue.

 

Gash MC?