Everyone with LS1, Explorer, Vette or other OEM rear discs

[1BadElky]

I just need to know what Prop valve and MC you guys are running. everyone on the G-body forums just tee the front lines and use an adjustable prop valve on the rear. I don't want to hack my brake lines, so just wondering if you guys run OEM proportioning valves.

Like 1LE, or 98+ Blazer, etc...

[1BadElky]

so of all the guys out there with 8.8 rearends, no one has any advice???

[Lays Low]

i have the 8.5" rear-end behind my 2003 4.3 5-speed, and didnt need a proportioning valve. maybe im just lucky.

oh ya, and i have rear disks from a 2003 ws-6 trans-am

[1BadElky]

thanks. BUMP

[usmc_noma]

i think you'll be good without running one. i was going to do this setup on my old sonoma but it was wrecked before i got a chance to put the discs on. after doing extensive research, i found that most who put it on didn't need the prop valve at all. the main concern was really adding washers to the backing plate so it sat off the flange, and also the parking brake cable. if you do a search on here i'm sure you'll find a whole how to on it. if you have an older model, you'll have to cut a little off the flange to get the backing plate up.

[tiresmokinV8]

Im running stock hardware with my rear discs, 8.8. I have found however that the abs kicks on a lot easier bascially anytime I slam on the brakes otherwise the rears would lock up. the rear do seem to catch a tad before the fronts.

[1BadElky]

I read that discs require less line pressure than drums, so with a drum prop valve they'd heat up and drag excessively?

[1stGen4.3]

Drums hold a bit of pressure against the lines constantly, discs don't. It really doesn't matter as far as I've found. If you want you can T off the front and just run and adjustable prop valve but you can just slap them on, the brakes WILL work with the regular prop valve. When I get home tonight I'll see how similar to the Camaro my S10's prop valve is (both are 1991's). If they're the same you can run a 1LE prop valve that can be had for around 60 bucks and will help all around on a Gm 4 wheel disc setup.

[1BadElky]

thanks, I'd appreciate it

[1stGen4.3]

The bodies look the same but the S10 runs what looks like 2 prop valves? Check out the pics.

[fishindabay]

one of them is for the rear ABS... its more of a little solenoid type thing.

[1stGen4.3]

That pic's from my 91, it doesn't have ABS, maybe they run a basic open prop valve and limit it down with the other block? I know the Camaro prop valves have a spring and plunger in the front that you can remove and block off with a pipe plug that will give you full pressure to all 4 wheels, I planned to do that if I ever did an adjustable proportioning valve for the rear.

[1BadElky]

IDK what that's all about. My valve looks different. I've seen third gen camaros with a valve on the front wheelwell/subframe that looks the same as mine... apperently there was a transition..

[1stGen4.3]

Apparently, the Camaro's also changed styles mid year and went from a big gangly bronze prop valve to a much smaller aluminum one. I honestly found the cheapest way to do a proper setup in the Camaros with the smaller aluminum prop valve like mine was to pull the spring and plunger, pipe plug it then run an aftermarket adjustable prop valve. Even the OEM replacement disc disc valves are about the same as an adjustable valve. The other option would be to forgo the stock valve all together and run the fronts straight off the master cylinder, then run an adjustable to the rears so you can get it balanced how you like it.