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Old 04-20-2024, 01:15 PM   #27
wrangler94
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Join Date: Jul 2008
Location: Washington, NC
Posts: 90
Re: HO 52/ HO 72 question

Quote:
I will just give a short recap on the axle.
-Axles were used from 1947 to 1972.
-The difference between the HO72 and HO52 is the factory load bolt.
-Axle shafts are 1.5in coarse 17 spline. Many argue whether if they are stronger or weaker then 14 bolt shafts.
-14 bolt axle shafts and the drop in (detroit, grizzly) locker fits in the HO72. There are some exceptions, on some older open carriers they are a tad narrower and do not let the 14 bolt locker unlock. Some have fixed this with washers between the carrier or machining a few thousandths off the side gear. I machined .008 off each side gear for a total of .016 and it now locks/unlocks like it should.
-some carriers are a few thousandths tight and the 14 bolt shaft wont fit. Bore it out a few thousandths to fit….it seems newer (closer to 1970 HO72s have larger IDs and 14 bolt shafts fit with ease
-14 bolt disc brake kits work
-Diff covers, I have found mine on ebay. Some guy makes a HD diff cover. Ruffstuff made a short run of them
-Some did come with factory 17 spline detroit lockers
-Factory gear ratios are 4.10, 4.57 and 5.14. Supposedly there is an elusive 5.86 and if I can get my damn hands on one I would.
-No gear sets are available from the aftermarket
-pinon bearings are expensive.
-Pinion shaft is BEEF at almost 2in in diameter with zero neckdown.
-Ring gear size is 10 1/8 (some conflicting info on this but its between 10 and 10.5)
-Yoke is 1350
-I havent weighed an Eaton HO72 but they are much easier and lighter to move around compared to a 14 bolt.
-Ground clearance is better when comparing unshaved 14 bolts to unshaved Eatons.
-WMS is 63 or 65in and determined by the hub
-2 types of pinion bearings, ball bearing and tapered roller bearing, the tapered roller is better.
If it was me, I wouldn't even consider getting rid of the Eaton. for one, for the originality, for two, they were one of the best axles ever built. If brakes are why you'd consider ditching it, do the disk brake swap. Kits are available for a 14 bolt and they work for the Eaton.
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