Brake bleeding problem??? Help.

Hello I come to you with my dillema.
Me and my buddy were bleeding my brake with the engine off and I would have him pump the brake pedal 10-15 times and hold it to the floor and over and over and over. So many bottles of brake fluid and Still no stiffness to the pedal, But if you pump the pedal about 50 times it gets stiff but spongy and the brakes work then. If I stop pumping them though they go away. So then me and my friend tried bleeding the brakes with the engine on, and to no prevail and many attempts pumping pumping pumping no stiffness to the pedal at all. Im stumped. Can someone please help me out?

Also I noticed when I had the metal cap off on the master cylinder after you pump the brakes the fluid would come shooting back up in the master.

Why exactly were you bleeding the brakes in the first place? Did you change parts such as the master cylinder?

I changed the the line off the splitter block to the flexible line on the drivers side. And put new copper pressure washers on the banjo bolts on both sides and the brake pads.

Also I noticed when I had the metal cap off on the master cylinder after you pump the brakes the fluid would come shooting back up in the master.

Sounds like your MC is toast. Get a new, not reman, bench bleed it, install and then bleed the entire system, RR, LR, RF, LF.

Well right now the LR,RR are not in use. And there not leaking at those lines either.

CherokeeEnthusiast said:

Well right now the LR,RR are not in use. And there not leaking at those lines either.

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1. When you replace a MC, which you need to do, you need to bleed the entire system.

2. That fluid shooting back into the MC is telling you the MC is toast.

Good luck.

Thanks Alot. But it would just go like that?

Yes.

Once the fluid started bypassing the MC's piston Pascal's Law is violated, you no longer have a hydraulic system.

WEll I appreciate but one more question when I install the new one and still not working. And also when I was under the hood while my buddy was pumping the brakes I could here a wooshing sound. Sounded like air leaking somewhere, coming from around the brake booster/mc area?

Bringing back a thread:
I'm having a similair problem- Brake system is completely new parts except for booster. Rear disc brakes, stock prop valve relocated on to the frame rail with zj spring and a brauded line which runs down to my front axle and out similair to the rear. I replaced the master cylinder because I thought it was leaking fluid past the plunger after bleeding the brakes multiple times where the plunger would contact the mysterious coroded far part of the mc body from bleeding the pedal to the floor. This didnt fix the problem and fluid shoots out of the mc which seems normal as other model do it and the old and new do it (nothing wrong) So I then gravity bled the system for almost an hour then normal bled it with an assistant 3 times on each and then cracked the fittings on the mc which let a little more air out and still goes to the floor while under boost and without boost if you press hard enough. I've had air in the lines before where I didnt run enough fluid all the way through on a different car and am getting similair symptoms in this case. (thats why I bled the crap out of it)

First, are the calipers on the wrong sides? Check, if the bleeder screws are pointing DOWN you will never get the air out of the system.

joe_peters said:

First, are the calipers on the wrong sides? Check, if the bleeder screws are pointing DOWN you will never get the air out of the system.

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Yes their pointing up in the right direction. I have also looked multiple times for leaks and problems which could have an effect. Also the proportioning valve the only thing I swapped was the zj spring and am using the xj end cap and plunger since I was using the xj body though I noticed some people using the zj cap and punger. Though even if this caused a problem it shouldn't be related to the main problem (just thought I'd throw that in there)

CherokeeEnthusiast said:

Also I noticed when I had the metal cap off on the master cylinder after you pump the brakes the fluid would come shooting back up in the master.

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That is complety normal just leave the cap on loose.

CherokeeEnthusiast said:

Well right now the LR,RR are not in use. And there not leaking at those lines either.

Click to expand...

If you have both rears not working there is still air in those lines and usually will find its way back up to the other lines that are in use.


When you bleed it make sure you start from the brake that has the longest run/distance. Actulay craw under neath and follow the lines.Be sure to hold the pedal, open bleeder, pedal goes to floor, close bleeder, let go of pedal and allow the fluid sometime to refill into the piston, usually about 5-10 secondes, and slowly at that time pump them back up and repeat. Do this untill you get a clean clear fluid with no air.

Also remember to put a piece of wood or something underneath the brake pedal so that it wont go all the way to the floor. That way when you are bleeding you wont overextend the rod and seals inside the MC. Could lead to premature MC failure.