I would check the rears and make sure the they are properly adjusted and clean. I have seen the lock up you are talking about when the rear shoes are reversed. I am assuming that you replaced the shoes since you referenced changing springs. They are not the same even though at first glance they may look like it. You have a leading and trailing shoe. It is easy to get them reversed.

 

I'm with Sungod. I honestly don't know why you would touch or replace the master cylinder since you didn't touch it before. It is full and pushing fluid. It should be fine. The info you gave says you only replaced the rear brakes (with an a).

Make sure they are fully bled. Also make sure there's no oil or leaks back there. Hopefully the brake cylinders aren't messed up. Then make sure the shoes and springs are installed properly. My first thought was he installed them wrong. Especially if they are lopsided on performance and grab hard like that. That definitely sounds like one side is not put on right.

 

I agree on the rear brakes possibly being put on wrong, but the way the peddle acts I'd still be looking at the master cylinder (reading panic braking causes the peddle to go to the floor) makes me think the seal in the piston is ok for light usage but not for high pressure usage like slamming on the brakes.

 

This was all happening before we changed brakes, springs and the adjusters. So i know thats not it.

 

It is possible that you brakes were put on wrong before. Most people when they install brake copy what was there before. If you are looking at the driver side the leading/primary shoe should face the front. It will have more friction material than the trailing/secondary.

 

Alright, we will check that too. Just going on down the check list, i'll be glad when this is over and the problem is fixed.

 

Putting the shoes on backwards is not going to cause the pedal to go to the floor. I agree that the MC is probably no good. At least that is what I would replace first, as they are not that expensive. Follow the directions it comes with and bench bleed it.

 

Putting shoes on backwards will cause them to grab. A bad master cylinder won't. It sounds like there is more than one issue.

 

A bad MC can cause both issues,given the right circumstances. Which is what is seems like here.

 

We are changing out the MC tomorrow. Hubby wanted to do it today and yesterday but work is getting in the way. But tomorrow he has the day off. I'll post and let you all know if it helped or not. I'm really hoping that it will. Thanks for all your suggestions.