Axle Swap

[Donald]

I have a 85 GMC 1500 short bed . I want to narrow the rear axle to 60" about 1.5" per side , tires hitting 1/4s . What GM corporate 8.5 axles will fit the 1500 axle housing and bearings . Will Chevelle , Nova , F body , or ? fit . I have tried to match up the sizes but it looks like the axle bearings in the 1500 are larger inside diameter than the car axles . I know I will have to change the bolt pattern , I am trying to stay away from custom axles . Don

 

[rpcraft]

perhaps you should just try a different wheel offset? Seems a lot easier because finding a slimmer axle is going to be not too easy and it will most likely require relocating axle pads and stuff.

 

[Donald]

I have the wheels I want , all the axles I mention are the length I need to make the overall width I need and I have enough axle tube to narrow with out moving the spring pads . What I need is a axle bearing the will adapt one of those axles to fit the 1500 housing .

 

[bucket]

I think the B-body cars used the larger bearing ends, but I don't know how the length compares. I do know there are several to choose from though. '71-'76 are probably too long, but then there's the '77-'96. The length might not have changed in '91, but I was told it did change when the full rear wheel openings came back in '93, and also the disc brake axles were a different length than the drum brake axles.

 

[Donald]

OK here is what I found , I can use 1970 Chevelle axles 28 spline and 1985 Impala bearings , cut 1.5" out of both axle tubes and redrill bolt circle That will make a 60" wide unit . Don

 

[Craig 85]

I'm not sure of the width, but just to throw it out there, the police package Caprices had the same bolt pattern as 1/2 ton trucks. 9C1 is the RPO code for the police package.

 

[Hondo78]

I have a 85 GMC 1500 short bed . I want to narrow the rear axle to 60" about 1.5" per side , tires hitting 1/4s . What GM corporate 8.5 axles will fit the 1500 axle housing and bearings . Will Chevelle , Nova , F body , or ? fit . I have tried to match up the sizes but it looks like the axle bearings in the 1500 are larger inside diameter than the car axles . I know I will have to change the bolt pattern , I am trying to stay away from custom axles . Don

There are a few Ford 9" and 8.8" rear ends that come in 59", 60" or 61". Tougher too. The 1973,4 ,5 Mark V and Continental town car have a disk brake 9" rear axle, it's 63" wide and they are cheap. It also already has 5 on 5 bolt pattern like your truck.
Everyone can shorten a 9". Or buy replacement axles with long splines and cut to fit with a cut off wheel.

 

[climb-101]

can cut down the axle tubes and weld new ends on. then just order a decent set of axles

 

[Donald]

OK , I did it , I ordered axles from Moser . The Chevelle axles are not as thick as the c1500's . I also ordered 3.42 gears and hardware . It is more money but everything will be new . Now all I have to do is cut the tubes . Thanks for the feed back to all . Don

 

[KilgoreTrout]

Well that's exciting.