ok so i just put a new hub on the front of my xj all i did to the brakes was take the caliper lose and now when i start the jeep the pedal is low to the floor it will pump up but as soon as i let it sit for a second and apply the pedal hard the pedal goes to the floor and the brake light on the dash comes on and no brakes please help im suppose to be goin wheelin in 3 hours lol

 

have you lost any brake fluid, did you check that area where you were working and look for a broken brake line?

 

Did you take the brake line off the caliper? Did a pad fall out that you forgot to put back in?

 

both pads are therein i didnt take the line off and ive checked everywere it could leak ive never had good brakes but never lost them like this

 

Master cylinder full (don't sound good for it though)? Try bleeding the system.

You never had good brakes like in......................

 

Yea master cylinder is full

 

Anyone around to help you bleed the system? Not thinking it's going to work but you should try.

 

4-Lo and trees to stop? But seriously - Does the pedal sit at it's normal height, or is it lower at rest? Does it go to the floor, or does it get hard at some point? When was the last time you changed your brake fluid?

 

it will pump up and be hard a normal hight but then u can take ur foot off then hit it hard and it goes to the floor and the brake light on the dash comes on

 

Wrong hub

Hub and rotors changed over the years. And having the wrong hub can cause this because it doesn't sit the rotor in the right spot

 

NAPA only shows one hub for an '89 w/4wd though.

Time's a wastin'! Try bleeding the system. Could be air in the system causing you to have to pump but so will a bad master cylinder. From what you described that you did I can't see how air got in the system. But you gotta start somewhere and bleeding is free except for a bit of brake fluid.

 

Doesn't mean it wasn't boxed wrong. It happens...a lot

To the OP, measure the distance on the old hub from the mounting surface where it contacts the knuckle to where the rotor sits on it. Then compare to the new one

 

The odds of a sudden master cylinder failure, or air somehow entering the system are very low.

If the problem occured after a new part being installed then you always start there, and investigate

 

I'd agree if he hadn't also said "I've never had good brakes".

 

Well ill leave it at that till we hear back from him.