Matt205

I have a 90 rs with drums, the rear end went out in it so I got a used one from salvage yard. It came from I believe a early 80 ' s z28, with disc breaks. Will this interchange without swapping master cylinder, prop. Valve, etc. Iv been told it shouldn't make a difference. Any help would be nice.

FRMULA88

I should not matter, the piston area of the rear calipers should be same as those of
wheel cylinders on the rear drums.

The rear disc upgrade will eliminate rear brake fade and improve braking performance.

Bolt it in connect the main brain line to the rear distribution block, bleed the system and you should be fine.

Base91

iTrader: (1)

It all makes a difference. Some years the master was different but I think the prop valve was always different. Do some searches on the Brake board. There is a ton of info on 10 bolt and 9 bolt drum to disc swaps and with the 'old' style iron brakes and the later PBR aluminum brakes.

Matt205

Thanks for the responses guys... iv got everything hooked back up. Had to get new calipers... now my caliper on the passenger side will not stop the wheel and the caliper on the driver side will not let the wheel spin. I'm gonna just do away with the ebrake. Because it's an automatic and I never use it. Any ideas on why the calipers would be doing this? Iv bled the brakes all the way around and they bled ok but still not doing what it should do. All help is very much appreciated.. thanks guys...

Base91

iTrader: (1)

Did you check the caliper carriers were centered on the discs? Made sure everything moves freely? No lines pinched? Assuming you've got the iron calipers. ?

Matt205

I'm at the understanding that the brake proportioning on this vehicle is set at 60 front and 40 rear wear. This rear end came off of a 82 model z28 the master cylinder and the prop valve were different in these years but iv been told by countless people that the change would work without getting a new master and prop valve, because 40 percent would be enough to work my calipers am I making any sense? Does anyone know for sure if I'd have to change the master or prop valve? This is a 82 to 90 rear end swap, rear worked great but I'm trying to get away from the drum brakes and this new rear end had disc setup. The only problem I'm having now is getting the calipers to do there job.

JamesC

iTrader: (5)

There are three combination valves: disc/drum, disc/disc (Delco-Moraine) and disc/disc (PBR). For best braking results, use the correct valve. That said, finding a valve that will fit your 91 will be an issue.

Check the brake info in the following link for more info:

https://www.thirdgen.org/forums/tran...-10-bolts.html

JamesC

Matt205

OK iv got everything put together and got it on the road today. I was able to keep stock everything and my rear brakes work fine. I believe this rear end was geared differently then mine. My speedometer was around 8-10 miles off. Tach says I'm running 65 but instead I'm running around 55-58. Any way around fixing this issue or will I just have to live with it?

Base91

iTrader: (1)

You can round the prop valve issue by using an adjustable prop valve but that doesn't address the brakes being locked. With the wheels off the ground and in neutral with e-brake off you should be able to turn each wheel with only a slight drag on the pads. If you have to, remove the e-brake cables to make sure they are not interfering with the set up. Did you make sure the pistons were moving freely in the calipers? Moving parts greased? Did you dis-assemble or replace any parts? Carriers centered on discs? Sometimes you need spacers to get it correct.

JamesC

iTrader: (5)

You have to change the drive and/or driven gears in the transmission.

JamesC

Matt205

What kinda Job am I looking at to change over the drive/driven gears in the transmission. Is there anyway to change the vss over from a older model camaro with this same rear end or is changing the drive gears my only option