Making a jig to narrow 8 3/4 axle housing

GTXJim · Post by **GTXJim** » Mon Aug 24, 09 10:55 pm

Hi has anybody got any plans for a jig to narrow axle housings, me and me brother are thinking about making one we've got a rough idea on how to make it, but if anyone has any input or short cuts to make one it will be much appreciated. We normally take them to Andy Robinson but we only want to take 0.750" off either end and there's enough spline on the half-shafts to cut down, so just to save a couple of trips and a few quid

black8driver · Post by **black8driver** » Wed Aug 26, 09 10:22 pm

usually u can cut the ends off stick the ends in a lathe and cut away whats left of the axle tube in the end..
cut down the axle tubes..
cut the shafts..
push the shafts back in with the bearings and the ends pushed back on and clamp a dial gauge on the drive flange running on the brake backplate flange sectin or the axle end.. tack ajust with a tickling stick (light hammer) until acurate easy this way to get withing 100th of an inch which is fine..
its easy it works and u dont need a jig..
really only need a jig if axle is bent of making a new axle
hope this helps..
and i have done many axles this way so its not just internet talk..

si

db · Post by db » Thu Aug 27, 09 8:53 am

Old Skool Cheapskate Mechanics.
Love it

Dave-R · Post by **Dave-R** » Thu Aug 27, 09 9:14 am

Most jigs are no more than a steel pipe the same size as the inside diameter of the axle tubes. That squares everything up so you don't have to worry about how square your cut is as long as you leave some tube attached to the back of the flange.

latil · Post by **latil** » Thu Aug 27, 09 9:42 am

You can make alloy buttons to fit inside the axle tube ends and at the diff end of the tubes,then pass an accurate bar through the buttons to align it all.

db · Post by db » Thu Aug 27, 09 2:46 pm

http://www.moparts.org/Tech/Archive/race/16.html

Dave-R · Post by **Dave-R** » Thu Aug 27, 09 2:53 pm

Ah that's it! I had remembered it wrong. Makes more sense that way.

GTXJim · Post by **GTXJim** » Thu Aug 27, 09 10:12 pm

Cheers guys, I'll let you know how we get on

Jim · Post by **Jim** » Fri Aug 28, 09 9:41 am

Narrowing an 8 3/4 rear end is easy. 30 years ago I cut a couple of inches out of each side of one (to fit it under a Volvo 123GT).

As I said, that's the easy part. shortening the shafts is a different matter. At that time it seemed a good idea to shorten each shaft by the required amount then get it re-splined. That's what we did, but after a few years easy driving (no racing) it eventually twisted on both shafts then one broke. This was with only a 318 up front.

So, by all means narrow the axle casing yourself, but buy the axle shafts made to length from the USA. There are several companies can supply good strong shafts to your spec's.

Blue · Post by **Blue** » Fri Aug 28, 09 10:14 am

I used to have a proper narrowing jig to shorten 8 3/4"s and Dana's. I just need to remember who borrowed it 25 years ago......

GTXJim · Post by **GTXJim** » Fri Aug 28, 09 11:19 am

Jim the shafts are 35 spline strange and there is plenty of spline as we really only want to take off 3/4".

Mick · Post by **Mick** » Fri Aug 28, 09 5:03 pm

You need to machine some pucks up for the ends, then just a bar or tube through the middle, jig to drop it on, i sleeved my tubes before welding.
Mick

black8driver · Post by **black8driver** » Fri Aug 28, 09 8:52 pm

db wrote:http://www.moparts.org/Tech/Archive/race/16.html

this is how i do them at work genrally but still tack a few times and run a dial gauge around it first.. with the jig alone it can still move significantly when welding.. a weld will bend a 2.5 inch solid bar along a distance like that the trick is to weld oposites the same speed and heat applied after it has been tacked.. and check it.. then some heat gently applied for a decent ammount of time will normalise it in that position to remove stresses.... although if the welds are even on a tube the stress should be equal anyway..
hope this helps..
si

GTXJim · Post by **GTXJim** » Sat Sep 05, 09 7:17 pm

Right, Axle all narrowed and back in the car, made all the difference 3/4" either side tires have a good inch clearance inner and outer also notched the brace for better clearance round the shocks and put the drag shocks back on, no need for the air shocks to jack it up any more,all that's left to do is bleed the brakes