no brakes?????

[bigrubbers4x4]

i put on all new brake lines from front to rear, bled them 4 times now, put on a new master cylinder (bench bled it before i put it on). when we bleed the brakes with the engine off they seem to have good pressure and get pretty solid, when i start the jeep, the pedal goes to the floor. i took it out for a drive like this and when i push the pedal all the way to the floor the rear brakes grab but it dont seem like the fronts are grabbing at all.
i re-tightened all the fittings, checked the power booster for vacuum and it has lots of vacuum, i am dumb founded. please, what the hell is happening with this brake system? its a 93 YJ with non-ABS, its a simple brake system so WTF am i missing? i am going to try and bleed them again tomorrow just to see if any more air comes out.

[supr_fly03]

When ever doing a major brake repair like replacing lines it takes allot to bleed them when done. If you have accesst to a vacuum or pressure bleeder, that is the most effective and quickest way to make it happen.

I have seen several people put new calipers on and put the calipers on backwards and wonder why they cant bleed the brakes.

The bleeders must be facing up to the highest point to let all of the air out. If put on backwards they will face down.

Make sure you dont bleed the master cylinder dry cause you will have to start all over again.

[sincitycj]

I just went thru the same issue on my CJ. I replaced the brake hoses with stainless steel and was amazed at how much air I had to pump out. Definitely don't bleed the master dry, don't ask I'll just blame it on the beer. Make sure your starting at the wheel farthest from the master and work your way closer. I will probably take several go arounds to get it all out. If you can get a vacum bleeder it will save alot of time.

[bigrubbers4x4]

well, i am on my 3rd master cylinder, 7th time bleeding the system and almost 2 gallons of brake fluid, i even tried it with bypassing the proportioning valve and going directly to the brakes from the master cylinder and still, they will not hold pressure when you start the jeep nor will they hold the jeep in place when its not running. this thing is pissing me off. they worked fine before i took the body off, i didnt change anything with the brakes other than new rear wheel cylinders and the new stainless lines. when they are all bled and you press the brake pedal down and release it, the fluid pushes back up into the master cylinder on the front side with a stream of pressure you can hear with the cap on and see with the cap off.

[supr_fly03]

Sounds like you may have a loose line sucking air or something. Check all of your fittings.