okay so i had stock drums on my 91 GTA, but i scrapped a 91 Formula and swapped the disc brake rear end to the GTA. i Also changed the proportioning valve. i topped up the master cylinder with the car up on blocks (level) and all brake lines open (not screwed into calipers) and began bleeding the brakes. so fluid start coming out the front lines so i connected them to the calipers and bled them. now the pedal is nice and firm and he car stops great on the front brakes only. THE REAR LINES ARE STILL OPEN and there is no brake fluid going to the rear end and the pedal is firm and up high.

whats going on?

 

Never heard of it being done like this. Sounds very messy. I think the prop valve may be the issue unless the rear lines are blocked or the calipers are frozen.

 

The light should be on (brake light).
You have to center the prop valve.
Usually, open the front bleed screw and stomp the pedal to center the valve.
It's centered if the light goes out.

 

You did re-connect the sensor wire to the prop valve. ??

 

Sounds like a 'gravity bleed.'

JamesC

 

yes it was a gravity bleed, worked fine on the front brakes, and i was going to do the back but if no fluid came out of the open lines, then not a chance of the calipers filling up, so i'll wait till some comes out the lines first.

i did reconnect the wire to the new prop valve.

I think it must be something to do with the prop vavle and i'll follow what dyno don said (thanks!!!) and see if i can center the valve, i think that will work. i'll let you know, this could be important step involved with a prop. valve swap.

 

If you sealed and bled the fronts without closing up the rear brakes then the prop valve would think the rear had failed and set the warning light. The light should be on if this id the case.

 

Sounds like the center rear rubber line is rusted shut inside.

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