I picked up a fourth gen differential today, it has pbr aluminum calipers on it, just wondering what brakes were available on the 4th gens, and what proportioning valve I should use with them?

 

you could get drums, lt1 discs, 11.25"? and ls1 discs 12". A disc/disc prop valve will do fine. A 1le prop valve would be ideal

 

With PBR's, I assume, the rear is a 93-97 (LT1); 98+ would be the LS1. Here's the pro valve you need:

https://www.thirdgen.org/forums/engi...rake-prop.html

JamesC

 

i actually did get a prop. valve with it, the guy said it was from a buick with either full disc brakes or very big drums. there is a number stamped on it, would that have any relevence? I can get the number tomorrow if that would help.

 

Since it's not thirdgen related, I'm clueless. The one in the link above is exactly the one you need.

JamesC

 

i wouldnt bother with the prop vavle you got with it, its not from a 3rd gen, so we dont even know if the thread sizes/flare type, port orientation, are the same, and we dont even know if its a disc/disc prop. Not sure where you could cross reference that number

 

Hollander.

JamesC

 

You need a 3rd gen disc prop valve for 1LE brakes, '89 and up. I have a few on hand and they're discontinued from GM.

Ed

 

how much would you want for one? I will have to wait awhile I spent all my money buying the differential. would it work okay if i left the disc/drum prop. valve in there or would the rear brakes lock up right away?

 

Sent you a PM. The drum one will work OK, I know some guys on here still run theirs but to be "correct" you need a disc one. They won't lock up right away, the drum valve just doesn't give the right pressure.

Ed

 

hmmmm..... better brake stands then lol

 

Ok so will I need to get the 89 and up prop valve since I have an 86 with the crappy iron calipers on the rear? I have 95 camaro rear calipers I'm just trying to acquire all the parts I need before I do the swap.

Thanks cameron

 

that should work, or get an adjustable one

 

ha sorry if I'm slow,so are you saying my 86' proportioning valve should work or that the stock 89 and up prop valve should work?

 

either would work, but the 89+ would be better, and an adjustable would be best, but I don't know for sure as I have yet to get the differential in(too cold to paint)