Rear axle change

[mike561]

I plan on doing this in the future, but i was wondering what type of car can i take a rear axle from that still has my 5 x 4.75 lug pattern but has rear disc brakes and posi trac? i was told a corvette or maybe camaro?

[old_master]

Check with your local boneyard, they can tell you.

[96capricemgr]

Not going to happen.
The Vette and Camaro stuff wont fit.
Disc b-body axles were 5x5 8.5" axles.

Probably the easiest thing to do would be get a 94-6 disc b-body axle there are two different widths, the police cars got narrower axles than the Impala, and redrill the axle shafts/rotors for 4.75" pattern.

Thing is a stock posi is not likely to be reliable for long. This would also be a 8.5" axle instead of your current 7.5" and you would need to address the driveshaft.

One thing that might work is use disc setup of an f-body and add a posi to your existing axle. Problem there is a b-body making much power is capable of breaking the 7.5", if you stay near stock output though no problems.

[PeteA216]

Sorry for the wordy post, but here goes:
Y'know, I was gonna ask this too, but it looks like some of my questions have been answered... I too want a rear end, limited slip, higher numerical gearing also, anything better than my stock 2.73. I would like to find a whole axle that has the 5 x 4.75 lug pattern, and probably a 8.5" differential, and no preference on disc vs drum. I've had no problems with drums aside from leaky cylinders. So my overall question would have been would I need a shorter driveshaft with an 8.5 inch rear end or is the size of the U-joint more of a concern? If I do need a different drive shaft, would as shaft from an '80s Caprice wagon with an 8.5 inch reary work in my '84 four door Caprice?

Also, my trouble with finding a rear end, is most, of not all of the limited slip reary's I've found in bone yards so far have at the smallest 5 x 5 inch lugs. The reason I want to keep the lug pattern is I already have a nice set of rally wheels for the car with 5 x 4.75 lugs, and it took quite a while for me to find these at such a great price. My overall question about finding a rear end is what cars would have one that would fit right into my car with the 5 x 4.75 lug pattern as opposed to the 5 x 5?

[mike561]

i dont really mind if i have rear drums or not, but i would like the posi trac setup though, and i do still need the 4.75 lug pattern so i can still rotate the tires as well.

[CD Smalley]

Why not swap the fronts to the 5x5 and get the bigger front brakes if you're doing all of this anyway???

[silicon212]

I have to agree with CD Smalley here - the upgrade on the front is the knuckle and rotor - that's it. The calipers you have will work on the larger rotors and knuckles (spindles).

That way, you get to rotate the tires when the need arises, and you also wind up with heavy duty hardware as well as increased braking ability.

[mike561]

Thats what you have done on your 9c1 right silicon? your lug pattern is 5 x 5 then im guessing

[silicon212]

Originally Posted by mike561

Thats what you have done on your 9c1 right silicon? your lug pattern is 5 x 5 then im guessing

Correct. All components now on my car came from the same '94 9C1 LT1 car.

[96capricemgr]

Just be aware GM was cheap and lazy and used a drum proportioning valve on the disc cars, so in normal braking the rear discs do almost nothing, under HARD braking they come alive.

I will try and find a good link on the fix for you, either you have to modify some things in the proportioning valve or you can buy modified parts and install them in your proportioning valve. Might be best to grab that from the donor car just so you have the spare to work with and just incase it is different from the old boxies.

I have had the 9.5" drums, the 11" drums and the discs all in the same car and the discs without modification are the worst. Have not done the proportioining valve mods yet though and that will fix it, I have just put it off because I want to do a line lock at the same time and have not gotten all the stuff for that yet.

[mike561]

Alright sounds good, i herd there was some type of conversion that can be done for the rear axle or something regaurding the differential?