Disc brakes and still pushing through help

[pearl91chevy]

I've done the rear disc swap from a 4x4 rear end a while back, actually about a year ago now.. I'm still running the stock prop valve but read on s10forum, and also I think it was summit if I recall, that you pull out the spring from the inside of the proportioning valve, and should be good to go.. Well I've always been able to push through the brakes around 6-8psi even on the 2step. What are you guys doing to the prop valve during a disc swap? And yes, I've bled the brakes numerous times and no leaks, and no air in lines, both newer calipers in rear with solid fluid streams when bleeding

 

[Static]

Re: Disc brakes and still pushing through help

I pulled my spring and valve out. Tapped the bleeder and installed a #8 screw. This is the front part of the prop valve, which does the rear brakes.

 

[pearl91chevy]

Re: Disc brakes and still pushing through help

Any pics of this?

 

[Don W.]

Re: Disc brakes and still pushing through help

Still with the stock vac boost? What used to be talked about here was to apply and hold the brakes then rev the motor letting it return to idle generating a tad more vac in the booster allowing more brake pressure in the system.

What RPM do you have the 2-step set for? If it's near or above the converter stall then you might just lower the 2-step setting.

IMHO you're gonna want some proportioning even with 4 wheel disks so the rears don't lockup to quickly in a "panic" stop.

 

[pearl91chevy]

Re: Disc brakes and still pushing through help

Usually when I go to brake boost, i rev neutral a good 3 or 4 times and I can almost get the pedal on the floor. I have bumped the 2 step down, I don't remember off hand what settings it's at, but still even holding a launch without it isn't very well. I know I can't compare really but I feel my stock typhoon with disk/drums still stops better then my disk/disk typhoon.

I have tried panic stops in my disk/disk Ty in past, tires don't lock up, but I feel it should stop much better then it currently does. I'm curious if I just pick up a disk/disk proportioning valve off a newer blazer it will solve my problems

 

[Don W.]

Re: Disc brakes and still pushing through help

I can almost get the pedal on the floor.

This may be the key. Pedal to or near the floor indicated air in the system to me. I know you said you've bled the system but.... With a helper try this. Have the helper apply nearly full pedal (IE pressurize the system) and then, starting at the right rear first open the bleeder until the flow almost stops. Close the bleeder, helper releases the pedal. Repeat. Keep very close tabs on the master cyl so it doesn't run dry or you'll be starting over.

After right rear do the left rear then the right front, finishing with the left front.

HTH

 

[Aeroking]

Re: Disc brakes and still pushing through help

Rear discs will not hold boost as well as rear drums.

I eliminated my stock prop valve, and just run an aftermarket wilwood valve on the rear. Open direct on the front, and adjusted the back until it locked up like i wanted.

 

[Z SKI]

Re: Disc brakes and still pushing through help

I took the guts out of a 3rd gen Camaro 1LE prop valve (made for four wheel discs) and stuck them in my stock prop valve... Only problem is I don't know exactly how they work as I haven't driven the truck yet.. They work fine in the driveway though!! Lol...

 

[Damian]

Re: Disc brakes and still pushing through help

I pulled my spring and valve out. Tapped the bleeder and installed a #8 screw. This is the front part of the prop valve, which does the rear brakes.

Why the screw? Does the bleeder not seat properly anymore?

 

[Static]

Re: Disc brakes and still pushing through help

Why the screw? Does the bleeder not seat properly anymore?

Don't remember where I found the info exactly, think it was the B-Body forum when adding rear discs. Pretty sure after removing the guts nothing keeps the fluid in anymore so you add the screw. I ran a tap thru mine and installed a screw with a drop of loctite. I would use a flatter screw next time. Anyways I removed the entire assembly, reinstalled the bleeder, and bled the crap out of the system again. Brakes pretty damn evenly as I recently had to make an emergency stop due to an oncoming vehicle in my lane of travel.

 

[Damian]

Re: Disc brakes and still pushing through help

Thanks, I'll have this done by the end of the week.

 

[cloneman315]

Re: Disc brakes and still pushing through help

H boost time...