I called Dutchman motor sports about building some custom made axles. The tech guy didn't recommend using the conversion bearing, which has a larger I.D. For use of 31 spline axles. He claims the weight of the car would put added stress on the bearing and could fail in as little as a few months. I told him my Mustang uses the same bearing from the factory and he says your Mustang doesn't carry the same weight. I don't really want to cut and weld new housing ends along with new backing plates,etc...... I know a few people have done this conversion ( Jim Nolan) and was wondering if anybody has had any rear bearing problems.
I'm a little foggy this morning and am not seeing the question clearly. Which bearing do you want to use and which one is the tech guy recommending? Any 9" axle bearing will carry the load of either a '57 Ford or a Mustang. Most '57s are no heavier than Mustangs especially the newer ones. I don't like the BIG, Torino, Late tapered wet bearing due to its poor sealing history and price. If it leaks, the bearing and seal are one unit and must be changed out together. I have seen the older, small, sealed bearings fail but at a far less rate than the Torino bearing that was changed just because it leaked. The Torino bearing is a better and bigger bearing and very rarely fails. But if the bearing and the seal are one unit and the seal fails...what's the difference!!!!
The '69/70 Torino CJ cars also used a 31 spline axle. I can't remember which bearing it used now.
It would be a benefit to actually have new housing ends and narrow your housing .75 on each side, as then you can run off the shelf wheels. With .75 off each end of the housing, it perfectly centers an 8" wide wheel with the common 4.5 Back Space. A 255-275 width tire will work with just a folding the inner fender lip flat in the right place. It also makes getting a wide wheel/tire on and off easier. The new replacement housing ends have a more common axle seal as well.
The money to narrow it .75 per side will offset the savings and availability on wheels later.
I upgraded to the large bearing on my sedan, as I planned to drive the Power Tours and always have a bunch of luggage in the trunk and back seat. I went up a bearing size as I did not want to take a chance while I was narrowing it slightly anyway.
The bearing I was originally going to use was the same one the cobra-jet/ Boss Mustangs use. It's the small O.D.(2.83) like 57 car but has the larger I.D. for 31 spline axles,I think it was 1.53 vs 1.37 for 28 spline axles. The tech guy suggests I cut and weld new housing ends to accept the bigger bearings. I agree the 57 custom I have can't be much heavier than a big block Mustang. The tech guy claims the added weight would wear out the small bearing prematurely.
My '69 MachI 428CJ four speed had the optional fold down rear seat (heavy) and was just over 3500 lbs.
It had 31 spline axles and I tortured that car and never had a rear end issue.
Same with my 70 Boss 302, many many runs at many road courses in the south east over a two year period and never an issue of any kind!
that's a good idea to narrow the housing a bit. I was looking to get 15x7 or 8 steel wheels anyway. Thanks for the replies guys.
Quote from: suede57ford on 2013-03-01 12:05
The '69/70 Torino CJ cars also used a 31 spline axle. I can't remember which bearing it used now.
It would be a benefit to actually have new housing ends and narrow your housing .75 on each side, as then you can run off the shelf wheels. With .75 off each end of the housing, it perfectly centers an 8" wide wheel with the common 4.5 Back Space. A 255-275 width tire will work with just a folding the inner fender lip flat in the right place. It also makes getting a wide wheel/tire on and off easier. The new replacement housing ends have a more common axle seal as well.
The money to narrow it .75 per side will offset the savings and availability on wheels later.
I upgraded to the large bearing on my sedan, as I planned to drive the Power Tours and always have a bunch of luggage in the trunk and back seat. I went up a bearing size as I did not want to take a chance while I was narrowing it slightly anyway.