Soft brake pedal after swap

[Bengler455]

Recently purchased and installed a QP 9" rear for my 84 Cutlass. Upgraded to the Wilwood Pro Street disc set up. I have bled the brakes countless times and still have a soft pedal and brake light on. Do I need to upgrade my proportioning valve? Anyone else have this issue? Thanks

 

[Built6spdMCSS]

Well, if you have Disc Brakes all around it would be wise to have the Disc/Disc Combination Valve, that is what it's called.

Then bleed it correctly, there is a procedure for them where you lock the safety piston in place.

 

[Supercharged111]

. . . there is a procedure for them where you lock the safety piston in place.

I'd like to hear more about this myself.

 

[Built6spdMCSS]

Little plastic tool, probably a vid on youtube. Just put it inplace of that sensor detent and bleed the brakes the normal way.

 

[Rocknrod]

This is a good explanation -

 

[Bengler455]

This is a good explanation -

Ahhh ok. Thanks. Looks like I will buying a valve and a sh*t ton of copper tubing. LOL

 

[Supercharged111]

So they mention the valve would knock itself off center and then imply it's a nightmare to put back in place. Same would be true if you ran the front or rear channel dry on the car. What would then be the procedure to re-center the valve? I'm betting that's what happened to mine and the OP's since his brake light is on which is an indication of that valve being off center.

 

[-dw-]

When I went to rear disc there wasnt even near enough pressure to the back. I tossed the prop/combo valve. I installed a wilwood adjustable prop valve. https://www.thirdgen.org/propvalve/

 

[Bengler455]

another option I suppose, good to know. thank you

 

[Supercharged111]

I guess it only strokes a tiny bit, so you just shove something pointy in there to wiggle it back to the middle.