replaced EVERYTHING and still have no brake pedal

[BPB]

I am out of parts to throw at my brakes. Not that it should effect anything but I have 3/4 ton chevy brakes upfront and 3/4 ton ford brakes in the rear bth front calipers are new as are the rear weel cylindars. I just put a new master cylinder in it today. Yes the master was bench bled. I bled about a half gallon of brake fluid through the system with a power bleeder. I tried pumping between bleedings. I replaced the load sensing proportioning valve with a T. My rear brakes are over tightened, so I know that is not the problem. My lines sat disconnected for about a year and a half. Could the return line from the rear having air in it be my problem?

 

[old_man]

I recommend a vacuum bleed, not a gravity, or even pumping the pedal bleed,

 

[IH392]

If you want to get rid of load sensing valve, I think you don't want to tee that line off because the fluid will go back to the proportioning valve. I think with my bro's comanche we just ran a single line to the rear brakes just like an xj. And we also switched out the mj proportioning valve with one from an xj. I could be wrong about this since I don't have the jeep. But I can double check if need be.

 

[BPB]

I recommend a vacuum bleed, not a gravity, or even pumping the pedal bleed,

I used my power bleeder, it straps on the master cylinder and preasurizes the brake lines so that all you have to do is open the bleeder screws. But I got it figured out. I eliminated the return line and hve a normal pedal now.

 

[BPB]

I recommend a vacuum bleed, not a gravity, or even pumping the pedal bleed,

I used my power bleeder, it straps on the master cylinder and preasurizes the brake lines so that all you have to do is open the bleeder screws. But I got it figured out. I eliminated the return line and hve a normal pedal now.

 

[TORX]

Front calipers on backwards? Bleeders on top?

 

[Andy in Pa.]

I am out of parts to throw at my brakes. Not that it should effect anything but I have 3/4 ton chevy brakes upfront and 3/4 ton ford brakes in the rear bth front calipers are new as are the rear weel cylindars. I just put a new master cylinder in it today. Yes the master was bench bled. I bled about a half gallon of brake fluid through the system with a power bleeder. I tried pumping between bleedings. I replaced the load sensing proportioning valve with a T. My rear brakes are over tightened, so I know that is not the problem. My lines sat disconnected for about a year and a half. Could the return line from the rear having air in it be my problem?

You can't just put a tee in the line to the rear. You'll never bleed it properly. Find the line that runs to the rear that comes off the FRONT of the prop valve under the hood. That is your rear pressured brake line to the rear. Remove the other brake line (that runs to the rear) from the prop valve under the hood and plug the prop valve where that line was. Remove the rest of that brake line and discard.

 

[tim500]

you need to get a master cylinder with a bigger piston. hydraulics function with volume as well as pressure. in putting on calipers with a larger piston naturally it is going to take more fluid to move them the same distance with the same force. i would use something from a late 70's as most of them had at least one axle with drum brakes, two pistons moving opposite creates a large volume that must be filled quickly.

 

[NW-ZJ-SCOTT]

so, driving it with no breaks was still less scary then mine?

 

[WB9YZU]

MJ brakes suck. Air gets trapped in the return line from the proportioning valve.

Delete the rear proportioning valve, and return line. Replace the MC with one from a pick up that uses the size of brakes you are installing.

The problem will magically go away.

-Ron