sellmanb

So I'm in the midsts of doing the LS1 brake swap. I just got a 9 bolt rear end with disks. My current assembly is a 10 bolt with drums.

Are the mounting brackets the same (so I can have Ed make me some brackets down the line for the rear as well as front) from 9 and 10 bolts?


I dont know what proportioning valve will work, nor do I even know where to start looking.

Do I need a new master cylinder to help out? Or does the stock one work? How about the brake booster?

Would a complete LS1 swap (brake booster, master cylinder, the calipers and rotors) work, with like a wilwood adjustable proportioning valve? Or can I get a cheaper prop valve that would work just about as well? I dont neccessarily need the MOST I can get out of these brakes, but definetly something to upgrade from my stock POS's.


Thanks,

Bobby

Stekman

Did you page through all 9 pages of the FAQ?

https://www.thirdgen.org/techbb2/sho...hreadid=183169

With my brakes, I run a LS1 master cylinder and the brake booster (redrilling needed, no big deal). Otherwise, I would look at the 1LE valve, sinces it's designed for rear disk setups.

I run the Wilwood Adjustable valve for the rears. Don't know about the brackets.

MurcoRS

While pretty much any 3rd gen 4-wheel disc prop valve will work the 1LE valve does allow the most pressure to the rears. A factory prop valve will direct fluid to the rears until a pre-set pressure is reached, at which point the valve closes and allows no more pressure. Drum brake valves allow too much pressure to the rear since they have to overcome the pressure of return springs and if you run a disc rear with that valve it will tear-up the calpers and rotors.

sellmanb

I'll be on the prowl for the 1LE prop valve then for sure.


Has anyone swapped to rear LS1 brakes? I would like to put them on all 4 corners, but all the adapter brackets seem to be for fronts only. Do you have to snag the whole assembly off of an LS1 rear end? Am I missing something plainly obvious?

ebmiller88

iTrader: (7)

I have a new 1LE valve on hand if you need it, LMK..

As for LS1 rears, here ya go:

https://www.thirdgen.org/newdesign/t...reardisc.shtml

Ed

white91formula

iTrader: (4)

got a question on that for ya....


say you have a 9 bolt disc rear end... will those caliper mounting brakets bolt right to it ? or will i have to modify them to get the mounting braket to fit correctly, i have searched and searched and cant figure this out

instead of drilling out the holes on the drum rear end

sellmanb

I'm in the same boat. I have a 9 bolt disk rear lol. I wasnt sure if that post was pertenaint to 9 bolts as well as 10.

If you still have that 1LE prop valve, how much do you want for it shipped to 97223?

88IROCARMY

Since we are on the subject of LS-1 rear brakes. I just did the swap on a 88 IROC with stock drums and prop valve. I bled it real good and the pads are used.
Well that old problem of being unable to stop the wheels on jack stands in Drive (idle) is still there. Meaning: the brakes won't grab hard enough. I could trying swapping the prop/combination valve. But, I think I will try the "Bolt Mod" first.

white91formula

iTrader: (4)

from a long night of searching for a answer... what i have come up wiht is that


YES the backing plates from a ls1 style rear disc set up WILL bolt to a 9 bolt just as the factory ones do

so LS1 brakes here i come !

ebmiller88

iTrader: (7)

Hmmm...where did you find that info? Not to flame you but I think you're wrong and here's why:

The 9 bolt has a different flange bolt pattern than a 10 bolt LT1/LS1 rear so it's not a direct bolt on, you'll have to redrill or cut on something.

I'll PM you guys on the prop valves today (Friday).

Ed

JamesC

iTrader: (5)

The following link shows the difference in 9- and 10-bolt backing plates and their flange patterns.

https://www.thirdgen.org/techbb2/sho...hreadid=246768

JamesC

white91formula

iTrader: (4)

ok so im going to have to redrill 1 hold on the backing plate to get it to mount correctly on the 9 bolt ? thats no big deal...

miacamaro305

guys on the tech articles it tells u step by step wat to do on a drum rear end to convert to ls1 brakes.so im guessing if u are already running a disc setup, it should be a bit easier imo correct?