Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

Your adjustment window is right there.

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

That's what I thought, and thought there was like a "star" shaped adjustment gear but as I spun the hub around and tried to use a light looking throught there to find it I didn't see anything. Pardon my ignorance here. Where (like clock position) should the window be to see, and what's the proper procedure for adjusting the ebrake a little tigher?

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

The window is for adjusting the shoe to drum clearance. If that is correct then you need to adjust the park brake cable at the equalizer.

Why do you feel you need rear disc brakes and why would you depend on a car rated caliper park brake for a 3/4 ton truck?

Service Manual Downloads
http://67-72chevytrucks.com/vboard/s...d.php?t=570059

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

Put the window at the 6:00 position.
Seeing the star wheel may be a little tough, since it is probably darkened up with brake dust.

The E brake adjustment is under the truck below the driver seat position.

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

Ok, thanks for the insight guys - that pic helps greatly.

Tim, I don't necessarily think I need the disc brakes out back- but from what I am reading it will be expensive and hard to find parts to rebuild the brakes should this eaton need drums and other brake parts down the line. I will be tearing the truck down soon and rebuilding from the ground up. If the drum brakes are serviceable, I will just run them awhile longer. I have the PB/PS from a 72, and will be finding some 73-87 spindles to upgrade the front to discs(although I hear the PB upgrade even with drums is an improvement).

This truck will not be used for seriously heavy work, although looking at the steel plate the PO welded in to the frame for the 5th wheel ball seems to indicate that it has been in the past. PO told me they used it to haul horse trailers.

I have adjusted the ebrakes as you suggested, and they are better. When I tear down and rebuild the truck I will be using another ebrake pedal assembly that is hopefully in better working order than mine. I just thought there was also an adjustment at the drum, I guess that's for the main brake shoes.

Thanks again for the help guys. Now if I could find a 4.10 third...

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

i checked on wheel bearings a t a napa store and its going to cost around 300 for both sides when i just replaced wheel bears and seal on a 14bolt for around 100 so i think ill be saving 200 on wheel bearings what do you think?And my spindles are pitted here and there on the eaton so i think ill replace my spindles with 14bolt ff's i can by them for 100 and there a fab shop that will put them on for me for 40 an hour or option 2 is i know a guy thats a welder for the gov. he'll do it for a case of beer plus i help out and lean. Beside i have a 110,220, and a 480 welder pluse plasma cutters and so on. i think i could do it my self but i want a cert. welder doing it... thank you for your support

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

Well I heard back from Right Gear & Axle. Their kit works with the non servicible drums. Once I find a donor axle for the brake parts I will order the adapter and let you guys know how it works out.
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Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

Wow, this thread is great. I think I know the answer but will a 14 bolt pinion support mate to the Eaton? If so then would a 14 bolt ring and pinion work in a Eaton? That huge Eaton pinion bearing most likely screws up that whole idea but i thought I'd ask. I want to keep my Eatons in all my trucks but 4:10s are really just too low for highway use these days. I've got 4:56"s and 5:14's too. Also the adjuster on the side, is that for pinion side load? My 63 unit doesn't have that.

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

The adjuster on the side is to prevent ring gear deflection. It is a common component on Heavy Line trucks like 18 wheelers, and such.

Interesting that you should ask that about the 14 bolt R&P. As for the 14B pinion support, no, it will not fit. The pinion support has a larger diameter than the eaton pinion bearing set. the 14 bolt pinion is longer, and the pinion pilot is different. One KEY measurement that I don't have yet is pinion height for the Eaton. the 14 bolt is -1.50". I have several axles torn apart at home. I will take pictures of the differences when I get home.

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

Here are some side by sides of a 14 bolt pinion support and the Eaton Bearing retainer.

https://lh3.googleusercontent.com/-5...112048_520.jpg

https://lh4.googleusercontent.com/-m...112016_992.jpg

Eaton pinion bearing and 14 bolt pinion support

https://lh3.googleusercontent.com/-c...112313_615.jpg

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

HO72 Pinion Bearings!!!!

National and Timken A1011
O.D. 4.330"
I.D. 1.9675"
Width 2.5"

National and Timken M5205EL (1.25" pilot)
O.D. 2.0472"
I.D. 1.2677"
Width 0.8125"

National and Timken MUB5205UM (1.00" pilot)
O.D. 2.0472"
I.D. 0.9843"
Width 0.8125"

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

This really is a great thread.
I had a question. (I'm afraid I may already know the answer)
63GMCkid mentioned that the carriers are somewhat similar.
Is there anyway someone could fit a posi unit in a HO72?

Thanks

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

I thought I posted this question once before but it isn't here so, asking again. Does this bolt on the side of the diff mean it's an HO72? Is this the basic difference between a 52 and a 72?

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

Good news from what I read here Nick, YES.

Get the Detroit Locker for a 14 bolt and use shortened, by .250" or so, 14 bolt axles. Look at THIS ENTRY for the "guts swap"

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

No the HO52's can have them as well.

http://67-72chevytrucks.com/vboard/s...d.php?t=595571

Here's some good info:

http://67-72chevytrucks.com/vboard/s...d.php?t=590959

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

OK I thing I got it. Decode the numbers on the diff is the only way to tell.

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

Does your SPID say if you have a 7200# or 5200# rear GAWR? I'll have to look into that more, but I can say the load bolt is not the difference. I think the brakes are the difference

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

I did see 7200# on the chrome tag on the door post. I'll post a pic. Also would the Aux Spring option G60 mean anything?

Here is Mr SPID

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

I need some help identifying my axle. I know its an Eaton 8-lug with the numbers HGI20 stamped on it. I have tried multiple Google searches and nothing. Any ideas anyone?

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

Probably going to have to know what year but also find someone that has a Rear Axle Identification chart for that year too.. Ir maybe try "Rear Axle Identification chart and year" ??

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

Maybe just an overload single spring?

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

I think BigDav160 was posting the G60 Spring option for Longhorn70... as for angryman117, I believe that the HGI20 (HG1020?) is a the gear ratio code for 4.57 for the Eatons. Eaton Stamped the ratios in the housing itself.

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

Jeremy I have a 1970 Chevy c30 Dually with a Eaton 72.Is the only difference is the length of the studs? Thanks Joe

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

Dually hubs are different than SRW. I don't have any pictures of the DRW hubs. They can be swapped over though.

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

Hi, I have a question about swapping a 68 HO52 brake set up to a 14 bolt 13" brake setup. You mentioned the bearings ahve different diameter, but the backing plate of the 13" brakes will bolt up to the HO52 housing, correct?

Now my question is, sure you could turn down the spindles and run the 14 bolt hub and make it work that way, but I was wondering, would it be possible to just turn out the bearing race diameter in the 14 bolt hub to accept the HO52 bearings and then bolt that setup with the original HO52 bearings onto the spindle?
I doubt that you can just use the HO52 hub, put the 14 bolt drum on it and mount it up, as your picture shows the 13" drum is deeper, so therefore the hub would come out further too and the bearing seats wouldn´t line up on the spindle anymore...or am I wrong? Is the backing plate of the 13" drums set in further, so that would actually work?

Could it be possible, I just take the 68 HO52 hubs, bore the stud holes out for the 9/16" studs, mount up the 13" drum and backing plate and bolt it all on the HO52???

Thanks!

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

Absolutely!!! if you cant source 71+ hubs, that is a very cost effective route.

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

COOL! So that way the bearings will stay in the same location and the 13" drum would still have the correct spacing to work with the backing plate?

That is awesome because I have a 8 lug D44 front that I could swap and have the 14 bolt with brakes as well. Therefore I´ll just mount the 14 bolt drums onto the HO52 hubs and be all set with a better braking system!

Thanks for the info!

I might try to find 71/72 hubs, if I can´t I just bore out the 68 hubs...

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

I have a 14B FF that I'm planning on mounting under my 54 3600 truck. I gave up trying to find a 4.11 gearset for the HO52, so I bought a 14B. My 14 is from a SRW truck, which is 67" wide. I knew I needed the DRW hubs to make it work, so I bought a housing that had been gutted, but still had the hubs. My original plans were to keep the factory style drum brakes. I found some 5.2" deep drums that would work from a van.

Well, one day when I was at the junk-yard I spotted an Express 2500 van with rear discs. I figured, "This could work." So, a couple months later I saw a rearend from an 03 van up for sale, anyway I bought it. The rearend was a D60 semi-floater. It had all the necessarry hardware, but to my dismay, the flange was different front the 14b. I wasn't too worried, there's plenty of shops that can fabricate them.

The Hubs and rotors.

The rotors won't slip over the early hubs, meaning they need mounted from the back, just like the drums. See here- http://s1074.photobucket.com/user/wh...97856697396817
http://s1074.photobucket.com/user/wh...97856697396817

I didn't like this arrangement for two reasons, 1- it puts everything really far inboard. 2- the flange isn't in a good spot.

So, I got to thinking. Why not the Eaton hubs? The Eaton spindles shafts are about .060 larger than the 14B, meaning I'll need different bearings. The rotor slides over quite nice and provides plenty of clearance before I get into the old flange. With the rotors installed the rearend will have somewhere around a 65" WMS, which is acceptable for my application. I need to have a flange made and weld it on. I'll have to get larger studs or use the tapered centering bolts from the Eaton hubs.

http://s1074.photobucket.com/user/wh...47396257023324
http://s1074.photobucket.com/user/wh...47396257023324

What I din't know in the beginning is that the brackets are availible from GM and aren't that expensive. Plus it's alot easier than pulling parts from a junk yard rearend. You can get new backing plates, hardware, and shoes from your local parts store also.

http://s1074.photobucket.com/user/wh...47396257023324

http://s1074.photobucket.com/user/wh...47396257023324

Bearings

14B axle- HO52 hubs

Inner- 382 Race (same as oem HO52/72)

Inner 387, 387A, 387AS, or 387S Tapered roller bearing (Same as the 14B)

Outer 362 Race
Outer 368, 368A, 370A Tapererd roller bearing

FYI- you can use he same brackets to convert your early trucks with the Eaton to Discs also.

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

well I don't know if mine is a 52 or 72, mine has a load bolt, 4.57 (if you do the math) so call it 4.56 if you want. it also has drums that resemble the 14bolt style, not the smooth drums that are normal for this axle. I never could find anything that showed the I.D. number I have on the top of the center section. also I do believe mine is an open carrier cuz I just see spider gears in there. I love these axles the more I read up on them. would LOVE one for the front !!! any help there ????

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

I've never seen anything that defininatively explains the difference between the HO52 and HO72. To the best of my knowledge, the HO52 has a 9.75 ring gear and the HO72 has an 11 inch.

With the "load bolt" I would lean towards it being a HO72, but who knows what changed throughout the years.

There are a number of kits out that that will convert a rear axle to fron axle use. The biggest problem I see is with the axle shafts. You'll need someone that can make a shaft with the Eaton spline pattern. I'm sure there's someone that can do it.

Here's some knuckles. Your tubes are 3 1/4" so the 3 1/8 are what you would need.

http://www.reidracing.biz/off-road-p...a-60-inner-c-1

http://www.reidracing.biz/off-road-p...ering-knuckles

14 bolt kit with lots of info.
http://www.cranehiclearance.com/crane_017.htm


I've heard of guys using Dana 50 knuckles from a Super Duty and fitting them to 14 bolts or D60s also.

Start choppin bro!

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

Thanks for the reply man. I'm going to need a locker for sure though. Not spending all that cash on a open diff. Guys where not joking when they said the bearings ain't cheap!

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

I want to say the difference between the 52 and the 72 is brake size. I don't think it got bigger gears until the 110 unit. I could be wrong though so don't take my word as gospel. You can use a 14 bolt detroit locker , but you will need to run the 14 bolt shafts cut down a little at the splined end.

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

RANGER- I don't think anything with the Eatons are cheap. Considering they haven't built the axles since 72, probably not alot of demand.

You may be able to source some alternative bearings by going to Timken.com, but I doubt it.

Another alternative is a Ford 9" front steer axle. The off road guys have been doing it for years. It has the same basic look as the Eatons, you might be able to fool some folks.

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

i actually just saw a 9" housing on craigslist and thought the exact same thing haha. the guy I bought my eaton from deals a lot with 4x4s and says he runs across these things all the time it seems like. so maybe he finds another one soon enough and I can make it happen. so with a 14bolt locker I just need the shafts cut down a bit and the side gears right?

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

Here is a build thread where a guy built a Eaton HO52/72 front differential. Unfortunately the build has been canceled and the parts are being sold off. Hopefully a member here ends up with the parts and does something with them.

http://www.67-72chevytrucks.com/vboa...d.php?t=504535

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

Ranger-

I'm not for sure about the specifics of the 14B locker in the Eaton housing. I saw a link awhile back but can't find it now. I know you have to but down the 14B shafts, but I believe you have to mill a little bit off the locker or differential carrier to get everything to fit. The 14B locker is just slightly wider than the Eaton carrier.

Boyce equipment has 4x4 GMC military axles also. They are seriously heavy duty. Would be kind of cool under a vintage truck though.

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

Man that dudes build is amazing. Pm was sent about the eaton front end so we'll see.

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

That was a pretty good build thread. Seemed like he went overkill on everything though and got burnt out.