Hello gentlemen I have a 1991 Camaro RS with the stock rearend and drum brakes. I also have a rearend from a 1995 Camaro Z28 with disc brakes. What do I have to know about swapping out the rearend in the RS for the 95 rearend? How will I have to hook up the brakes? Thanks for any input. Thanks.

Anyone?

Unbolt the old, bolt in the new. Really, its that simple! No changes NEEDED.

You should consider getting the correct prop valve for rear disk brakes. And the proper gears for the speedometer.

Info in the following link will be helpful, concerning what needs to be changed in the swap:

http://www.thirdgen.org/techboard/tr...-10-bolts.html (FAQ About 10-Bolts)

JamesC

But PLENTY of people have swapped from drum to disc, without touching the prop valve & have been perfectly happy, and had no problems.

Like using the stock wheels. They SIT out farther, due to the wider rear end, but not stick out past the fenders & look bad. IMO, they sit NICE & give you a tougher look to the car.

I've posted pics of stock 3rd gen rear wheels on a 4th gen axle a hundred times showing that.

They may have been perfectly happy and had no problems, but they aren't experiencing the best brake performance. Swap the prop valve.

JamesC

Funny how you post a link to a thread that shows a GM Broadcast that gives dealers directions to install a disc/drum prop valve assembly, on 4-wheel disc cars, yet you say "for best performance".

If GM says its perfectly acceptable to install a disc/drum prop valve on a 4-wheel disc car, and YOU say otherwise..........

The 95 diff is no stronger than the 91 diff. It's slightly wider so your rims will stick out a little bit. All you're doing the swap for is to get disk brakes. There are plenty of aftermarket disk brakes available that are better than factory brakes.

Perhaps you'd better revisit the link, then get back to us.

JamesC

Done (i knew you'd say that) ....... http://www.thirdgen.org/techboard/su...fferences.html (Master Cylinder Differences)

PLEASE people!

STOP saying STICK OUT!!!! They DO NOT "stick out". That implies past the fender lips, which they DO NOT..DO NOT...DO NOT. They SIT out father, just like if you put front 16"s on the rear of the car.

They stay UNDER the fenders!

Really...This it getting OLD....

You'll note that the link has to do with master cylinders, not proportioning valves.

JamesC

I'm willing to admit to my mistakes, but the fact remains. PLENTY of drum to disc rear swaps have been done & no complaints. Some have swapped the prop later "because its the correct way" & they said they didn't notice enough difference to have made it worth the effort to have done in the first place.

Reason would dictate that GM designed different proportioning valves to maximize specific braking systems, disc or drum; otherwise why not simply authorize a one-for-all fit and be done. Using a valve that lessens braking efficiency is not the best choice, IMO--though, of course, each hobbyist should do what he/she feels most comfortable with.

JamesC

Damn, that's easy. You guys are awesome. Thanks.

My RS has a 305 TBI so I would assume my rearend is not very great. (Don't know what rearend I have, actually.)
I would think that a rearend from a 95 Z28 with an auto and 350 LT1 would have better gears.

edit: I just read through the above link. I will find out when I get out of work what gears I have.

Most likely, your RS has an open diff, 3.08 gear. And, most likely, the 95 Z28 has a 3.42 Posi.

Same axles (except the length) but better center section, because of the posi (limited slip for the nitpickers!) & gear ratio.

Because of the ratio change, your speedometer will be off, but that can pretty easily be fixed. And until then, just find out how far off the speedometer is & keep that in mind while driving around.

I have a differential from a 95 z28 i just put on my 86, i didn't change the prop valve, but when i hit the brakes as hard as i can on a dirt road only the fronts lock. So it would be a good idea to just get an adjustable prop valve.

Is the design supposed to lock? The following from MurcoRS:

"Proportioning/Combo valve - Our cars use a 3-function combination valve (proportioning valve, metering valve, and brakelight warning switch) and are prone to many of the same problems as the master.
The prop valve is an umbrella-shaped seal that ONLY REACTS AT PEAK SYSTEM PRESSUREs! It is designed to keep the rear-end from locking-up and is designed to close off the rear brakes at a specific pressure, allowing no additional pressure. The excess pressure is fed to the fronts.
The metering valve is designed to pressurize the rear brakes FIRST, under light pedal application, to promote more even braking. On drum brake cars it can hold up to 125 psi before allowing any fluid to the fronts, simply to overcome the force of the return springs and engage both front and rear brakes simultaniously. Disc/disc metering valves operate at lower pressures as it only takes about 3-5 psi to move a piston.
If EITHER of these valve fail or the springs are weakened, you will have excessive brake wear on one end of the car. Drum to disc rear conversion? CHANGE THE COMBINATION VALVE DURING THE CONVERSION or you will tear up your new rear brakes!"

Here's the link in its entirety:

http://www.thirdgen.org/techboard/br...air-101-a.html (Brake diagnosis and repair 101)

JamesC

treated.

You guys really are something. Drum brake use the pressure of the brake fluid, while disks use the volume of fluid, or viseversa. Either way, something as simple as changing the prop valve to the proper one is a pretty simple decision. It's not hard, time consuming, nor expensive, so why wouldn't you want the "right" prop valve for the disk brakes? If your gonna go through all of this, why not get the right valve to maximize the mod?

I guess some of us agree with GM, that a disc/drum prop valve is good on a disc/disc car........And some of us don't.

I need said NOT to. I only said you don't HAVE to. But, personally? I wouldn't swap the prop on my car.

Where in the world does GM say that?

JamesC

Master cylinder...WTF ever...You understood what I meant.

We can piss & moan about this BS technicality all year. Doesn't change a thing......

IT IS NOT REQUIRED THAT IT BE SWITCHED. Some do, most don't. Do whatever you (the OP) wants. It doesn't matter.

glad im not the only one who argues on this site lol.

Good grief! I'm too amused to discuss the issue more. I'm done.

JamesC

See it does make a difference. The master cylinder is interchangeable, disk or drums. But the prop valves are different. One flows more pressure, the other flows a greater volume of fluid.

Yeah, disk brakes will work with a drum prop valve. But the prop valve is cheap and easy to replace. So why not do it and get the most from the disks, not just, they work.

Agreed