yatwich

I recently bought a 89 Iroc convertible. As you know the rear disc were not an option. Ive come across a GT4 rear end from a 84 trans am with posi, 3.73, and disc. My question is will this work without mods or gear changes and am I wasting my time with this "upgrade"? Thanks for any insight, Gregor.

jstoltz

iTrader: (16)

it will bolt in no problem and there were verts with disc brakes.

Destructimus

Typically when you go from drum brakes to disc brakes you need to change the hydraulic pressure being fed to the discs because of the larger pistons in the caliper. The best way to do this is with a proportioning valve. There is a tech article here on how to install one and they go for around $40 on ebay.

hotrodhoney

I have an 86' I -roc Z, it's a t-top. my car currently right now has disc up front and drums in rear. I'm gonna switch that 10bolt out w/a 9bolt out of a Trans Am. So, my car too will let alone have a stronger,better built rear,but also have 4 disc stopping power.The husband and I plan on upgrading the brake booster,the porportioning valve and break fluid reservoir, to accomadate for the added disc braking power. hope this helps and good luck.

kelly

allgood

i have 92 ws6 ta vert and want to put rear disc and postitve i now it have the limit slip on now

Camaro067

Sine i'm doing a open diff/drum to posi/disc swap, i was curious exactly what years fit how. 82-92 will all bolt up the same way and are the same width, but the 93 and up rear ends are slightly wider but will bolt up no problem anyway? the only things to really concider are the gear ratios and brake conversions right? thanks

gmgod

Correct, just don't use the 85-89 rear discs. They suck.....bad. The drums work about 100% better.

JamesC

iTrader: (5)

I've heard that many times on this board. My personal experience with that set-up (82-88 Delco-Moraine calipers with 10.5" rotors), with the "fit kit" in place, was positive. However, the 89-92 PBR's are preferable. Here's a how-to to upgrade to them from Delco-Moraine's:

https://www.thirdgen.org/forums/faq-...iscs-89-a.html

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Posi = limited slip.

Camaro067,

Adding your car's info (make, model, year, etc.) to your profile will make answering your questions easier.

JamesC

allgood

so whats the diff in rear axle, i have 2.73 gears