I have a 1990 camaro RS 3.1L v6. the rear broke (dont ask how), I searched the archives for info on a drum rear to disk swap. I have a chance to get a disk rear for a good price. what do I need to make the rear work well or is it just a regular swap??? please reply!

 

I've found that the rear disk setup is a major pain. The parts are disgustingly expensive and seem to need constant attention... you'd better be getting a real sweet deal on it because a V6 certainly doesn't need the slight improvment in strength.

If you want to swap you need: the diff, master cylinder, proportioning valve, and e-brake cables from the donor car.


------------------
1986 Trans Am
carbed 350 - .30 over with 9.75:1 comp.
+- 315hp/390ft lbs.
700-R4 with 2500 stall
3.27 (ick!) gear
SLP 1 3/4" headers w/MAC catback and cat.
96 5 stars
SFC's, braces, arms, and a bunch more expensive stuff
no timeslips yet

 

I thought that the rear disk would give me a major improvement? am I wrong. Is the 1Le setup what I really need to stop really Quick. what do I really need to improve the braking of my camaro

 

btt

 

You do not need 4 wheel disks. It is a nice to have but not really easy to convert. You won't notice much of a difference anyway. I would just replace your rear or have it rebuilt and keep the drums. For all out performance, go for 4 Wheel disk, otherwise, put the effort in to something else like a 350 engine.

 

Thefastest, you should check out a mid-80's MPFI 2.8 f-body for it's axle. Those cars came with 3.42/open/drum axles; and if I'm not mistaken, your '91 3.1 has a 3.23/open/drum axle. You'll notice an improvement from the better gears. Keep the gears in mind; if you wind up with a 2.73 from a disc-brake-equipped f-body, your car will feel sluggish in the 0-60 and quarter mile, and you'll probably hate it.

Also, it depends on which disc brake rear you find. 82-88 was a "bad design"... 89-92 is the better one. If you get an 82-88 axle, chances are, the calipers won't work, and you'll need to spend +$200 at GM for the TSB/Recall parts. If you get the 89-92, the brakes will work...

The only axles with 3.73/posi/disc were under the 83-85 Trans Am's and Z28's with manual transmissions. Watch out for 82-83, those years used SAE brake line fittings- all 84-92 (actually 84-2001) f-bodies use metric fittings. If you wind up with an 82-83 rear, it's not the end of the world, but you'll need adapters or new lines or etc to bolt the 82-83 brake system onto your car.

Another "rare" car, the '84 Camaro H.O (says Camaro H.O. on back bumper) came with a 3.73/open/drum axle. I found two; both with their axles gone.

If you ever see a 4cylinder f-body (2.5l I-4) with a manual transmission, chances are pretty good that car's got a 3.73/open/drum axle on it.

As a side note, GM did not build a stronger axle for v8's. A V6 and I-4 axle will be just as strong as a V8 one. There was a move in '89 to a "28-spline axleshaft", but even the V6's got that.

When you do the swap, please, please, please buy new brake hoses for the back. I scored my Raybestos hoses from carparts.com. I went to Yahoo.com, and searched for "carparts.com coupon" (without the quotes), and found a "$50 off $100 order coupon". I scored new rear brake hoses, new rear e-brake cables, rear wheel bearings & seals, a caliper rebuild kit, and some caliper bolts & bushings & slides for only $65 (would've been $115).

Bleeding a master cylinder is a major pain in the butt. The good news is that for 89-92 f-bodies, GM used the same master cylinder for either rear discs or rear drums. So if you find an 89-92 rear axle, you won't have to change the master cylinder.

GM sells proportioning valves in case the junkyard car you're getting the axle from is long gone. I believe they wanted $80 for one. Absolutely, postively, do NOT unscrew any ports of the prop valve. Some look like they're "universal" for the location of some brake lines (seems to be mainly 84-85 models), but those ports are sealed and have valves inside 'em. You can also buy an adjustable proportioning valve from a company such as Wilwood (thru Summit Racing), but you'll lose your "BRAKE" warning light (for low or unequal fluid pressure).

Swapping the axle itself is cake; maybe an hour's job; it's the brake system that'll break your back.

Oh- make sure you pop the cover off the junkyard axle. This does two things- you can make sure it's got the gear ratio you "think" it has, and, you're making sure the gears aren't trashed beyond belief.

As to improving your stopping power, some stainless steel brake hoses (from Russell or Earl's, thru Summit Racing or similar) will help, as will some performance brake pads. Flushing your brake system with new fluid will also help. You can do a "gravity flush", where you loosen a bleeder screw at each wheel to let brake fluid ooze out as you pour new fluid into the master cylinder. Search the archives for "gravity" and "brake fluid", you should find the info. As brake fluid ages, it sucks in water and dirt, which lowers the boiling point of the brake fluid. New brake fluid is clear; take a look at the color of your old stuff!

I did this swap on my car. I managed to find an '84 Trans Am with it's rear axle; it had a manual trans and engine code "G" (think "G" for "Gold"!), I popped the cover off, and sure thing, it had the 3.73's underneath. I paid $150 for the axle, and over $600 to rebuild it and install it. That money would've gotten me "new" 3.73 gears, a posi unit, 28-spline axles, and paid for gear installation. Oh well- I'm not that upset.

------------------
-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards
---Think your car could be pic of the week? Visit http://www.f-body.net for details!

[This message has been edited by TomP (edited July 11, 2001).]

 

Great tech articles on the rear end swap.

http://sethirdgen.org/10bolt1.htm

http://sethirdgen.org/10bolt2.htm

http://sethirdgen.org/10boltinstall.htm


------------------
86 Camaro Sport
383 Speed-O-Motive Crate Engine, Raptor 700R4 Tranmission, Trick Flow Twisted Wedge G2's, 58mm Accel TB, 3.73 Auburn Pro, SLP Cold Air Induction and Headers, Hooker Cat-back, Serpentine Belt Setup, Dual IROC Fans, Jamex springs, 16" IROC Rims, 36mm/24mm Sway Bars, Global West Steering Brace. Hotchkis Rear LCA's,Panhard Bar and SFC's.
My Camaro Project

[This message has been edited by John Millican (edited July 11, 2001).]