How to narrow a rear housing

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rod7515

rod7515

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Im thinking I might want to have the 8 3/4" rear in my 66 Dart narrowed do to clearance issues. I bought new axles from moser back about 15 months ago and havent used them yet. The few questions are: can I cut the splines shorter or would they need to be resplined once cut? Is narrowing something I could do here without buying jigs or special equipment. How do I cut to be sure to keep the flanges straight?
Are there any good threads on this?
Thanks
Rod
 
rod7515 said:
Im thinking I might want to have the 8 3/4" rear in my 66 Dart narrowed do to clearance issues. I bought new axles from moser back about 15 months ago and havent used them yet. The few questions are: can I cut the splines shorter or would they need to be resplined once cut? Is narrowing something I could do here without buying jigs or special equipment. How do I cut to be sure to keep the flanges straight?
Are there any good threads on this?
Thanks
Rod
Click to expand...

Having done this once before but on a ford 9 inch, let me say first, sell the moser axles for whatever you can, or return them to moser and get the correct ones, resplining isn't cheap and costs almost as much as new moser axles. And yes, they'd need the correct length splines in.

To cut one down, don't use a plasma or saw of any type, you need to source a big tubing cutter similar to a pipe cutter used by plumbers. Get one with a carbide wheel if you can. This will keep the cut as straight as possible. we did dads on a home built jig and it worked very well to keep the axle straight. Also, measure 10x, cut once.

You might hunt around your local area and see if someone locally has the experience to cut and weld it for you. Race shops, engine shops and your local drag strip would be places to ask around.
 
If you narrow a housing and don't use an alignment bar with spacers you run the risk of not having your axle bearings parallel on the same centerline as you carrier bearings. I know there are tons of individuals who have shortened housings without a jig or bar and had good luck. There is a risk you will not get them close enough and your axle bearings will wear out quickly. I wouldnt shorten one without an alignment bar and spacers. You also need to use the bar/spacers to check your housing after welding and to get the housing bent straight. You can buy a turned/ground/polished(TGP) bar locally and spacer off the Internet for a total sum of $100-300. I have access to a lathe, so I turn my own. Use a bandsaw, chopsaw, or pipe cutter to cut the housing.
 
On a cutter axle the splines only engage about 1" but they are splined about 4 inches. I dont see whey you couldnt cut them down 2" per side but the cut would have to be very straight. I helped with a guy (and did a Ford 8.8) and we just shortened one side so we had the short side axles and just needed to trim down the long side of an 8.8, pretty common project. We didnt use a bar, it was absolutely hillbilly but it worked out fine. The pipe cutter is the key. We knew how much it needed to be cut and just sectioned out a piece and rewelded. we used the axle in the floating piece to line everything up. Basically it was just lining up the tubes and tacking then running a bead. The ford housings are straight pipes out of a cast center with plug welds, the Mopar is sort of tapered so be aware.
 
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