Hey all,

I recently picked up a 2002 LS1 rear end, with disk brakes. Being that I wanted a taller gear, and posi, I figured I might as well go to disks while I'm at it, however I've got a few questions.

Besides the proportionate valve, what all am I going to need to swap/do to get the disks working? The car it's going into is a 1992 Firebird with drums.

 

Anyone?

 

Are you planning on swapping rear ends, or just the gears and brakes?

I think your car has the 4 wheel disc brake valve, but I'm not 100% positive. I'm pretty sure that all '91 and '92 cars have the 4 wheel disc valve, it's either that or just the '91 and '92 Z28/Trans Am modesl. I'm not for certain about the V6 models. Someone will probably chime in and either verify or correct me on this one.

As for the rear end, I'd suggest just simply swapping the entire rear end in your car, but then you'd need to run a 4th gen offset wheel to make it look factory (no changes in wheel distance from the fender lip).

 

Okay, I guess I didn't describe myself here. I am swapping the entire rear into the car. I have drums right now, and I need to get these LS1's to work.

I know I'm going to need a prop valve, however I was told I'm also going to need a new master cylinder?

I just want a definite answer and to what I need and what I need to do to get these puppies working.

 

No one?

 

See I don't think you need either of those. I swapped an entire LS1 rear end into my car and didn't change a single thing on my car with the valves and master cylinder. It's all the stock stuff and it works great. I was told '91/'92 cars came with 4 wheel disc brake parts even when they had drums in the back.

 

Can you take a pic of your MC and stock valve? If it looks similiar to mine I might just say screw it, and swap the rear with the stock stuff and see what happens. Problem is, this car is my daily, so I don't want it to be down and out for too long, hence I want to know what I need to order it all and do it in a weekend.

 

just swap it and if you feel the brakes arent working correctly then swap prop. valve.

the MC is the same

 

That's what I needed to know, thanks!

 

You need to swap master cylinder because they have different cylinder bore diameter, and it will effect pedal travel, feeling, and pressure force. Bigger bores give less pedal travel, and firmer feeling pedal; on the other hand, smaller will do the opposite. Do it right, you can get a rebuilt MS for $20

 

do you have PN's ive never had the option come up

 

Kragen # 101997

http://www.partsamerica.com/ProductD...pe=230&PTSet=A


Napa # ts 101997

http://www.napaonline.com/MasterPage...linder+-+Remfd

 

From what I've heard, 88-92 both disks and drums have the same stock prop valve. So all I'll need is a new MC with the proper bore, and that's it?

 

The parking brake lines are different. And if the car had traction control/abs then the fitting on passenger side line is different [the one that goes into the banjo fitting] is different then stock.

Im going with no new MC or prop valve for my set-up. If it doesent work then I have a wilwood prop valve on hand, would just have to install it.

Some people said they did nothing and it worked find, some people did the MC, some did the prop valve. So their is no real definite answer I have been able to find.

 

Like I said I didn't change the prop. valve OR the master cylinder and mine feel awesome. And the rear end I swapped in did have ABS, so I just plugged the hole for the abs sensor with a bad sensor from a junkyard.


You DO need to get the LS1 brake lines, make sure you have those handy before you put the car on jack stands or you will be upset when you find out the 3rd gen brake lines are too short to reach the calipers. And like someone else said, the ebrakes are different, you'll need to get the LS1 ebrakes and I believe there is a simple modification that needs to be done to them before they work. I haven't hooked mine up yet and I've had the rear end in my car for almost a year now. But I have an automatic, I don't know if your car is a manual or not but that might be something to think about.

Also, I hope that you are planning on replacing the fuel pump while you're in there? You might as well, as you'd be so close to having the fuel tank out anyways while the rear end is out of the car...

 

You have the proper master. "Master Cylinder: p/n: 18014286 - Same as the J50 option drum brake equipped cars from 1984-up." From Dan Burke's write up. It's what I used on my 1LE set-up. Conventional board wisdom, IIRC (and I'm getting old), says to swap the proportioning valve.

More about the master that should prove interesting:

https://www.thirdgen.org/forums/susp...fferences.html

JamesC

 

looks like performance wise it matters not. just comfort?

Why is everything 84-88 would it be safe to assume 89+ (esp mine being 91) is all the same

 

Rear offset STOCK wheels on a 4th gen rear are a great fit & do not stick out. No need to change wheels right away.

 

I am currently using the stock MC and stock Prop valve on my daily driver.
It stops great on the street and on the track.
I am using 91/92 Camaro e-brake cables on my car as well.

I used a set of Tru-Torque cables, C94597, $18.88 each.
The sheath is barely long enough and the inner cable is 1'2" too long so I used skinny u-clips to take up the slack.
Cables need to run under the sway bar so that they will reach.
Had to dremel out the inside of the fitting that goes over the hook on the caliper, took a few minutes.
Brakes work great.

https://www.thirdgen.org/forums/brak...er-ebrake.html

 

89-92 cars have the same master, but I believe the proportioning valve is different between J65 and J50 cars.

JamesC

 

explains why I never had the choice for disk or drum.

I think i will still default to laziness and swap the disc rear when i get it without the prop valve.

 

I'm **** about such things, so I'd probably try the disc/disc valve; however, many members are apparently satisfied with the drum valve. That being so, I'd "guess" there isn't much difference between the two.

JamesC

 

Yea i feel that....

 

When i had my 91 with an 87 9 bolt in it with the crappy rear brakes, it always used to pull to the left when stopping. Now that i have my 4th gen rear in, i swapped in a 92 disk/disk valve and that went away, i had one on hand anyways, i also replaced all the rubber lines for both the front and rear brakes. I have never really understood how the prop valve for 91-92 drum/disk cars could be the same as 91-92 disk/disk cars.

 

No complaints here on my 87 9-bolt.

Brakes aren't crappy..Car doesn't pull...Brakes do not lock up....

In fact, I went to empty road & tested my brakes...If my seat belt hadn't been on, I'd have been in the dentist office looking for new teeth. Hell, it stopped so far, I got a light headed & dizzy. Any faster stopping & I WOULD have passed out, which means my foor woulda released the brake pedal, and the car continued on by itself, with an unconscious pilot. Who knows what I woulda hit, but that would be a BAD thing to happen, on am undivided highway. Can you say, 'Head on collision.'?

I'm quite happy with my 87 9-bolt brakes.

 

lol you're a character stephen

 

Just telling how my brakes are. If Saber thought his were bad, maybe it had more to with his pads/rotors or prop valve, than anything else. When they work, they work good.

 

I did the samething that BlueZee did, and no issues at all, (9!-92 car have the same brake stuff nomater the braking config.......Put it in and you will have no issues with braking

 

Oh i wasnt talking about the stopping power of them sucking, just referring to how they sucked cause there all iron and looked pretty nasty compared to a set of the PBR rear brakes, I know my 87 9 bolt brakes worked pretty well, aside from the pull, when applying the power, but the PBR's work tons better.