Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

Maybe this will help, others may be able to use this info.

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

Following...

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

Has anyone swapped a H072 from a 1965 C-30 to a 1967 C-30 Cab and Chassis?

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

I would think they would be pretty close in width, I kicked out the ho72 from under my 52 for a 80s 14 bolt. Have to move perches and shock mounts, u-joints look different too but haven't got that far

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

I would think it should be a direct swap. Personally I would go with either a 14 bolt or a Dana 60 or 70 before I would bother with a Eaton HO52/72.

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

Just got a measurement on both.
It’s 47” plate to plate on my 67 and 46” on the other.

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

That is not an accurate to measure a differential's width. You must measure WMS to WMS (Wheel mounting surface). That is the dimension that matters. Not all brakes are the same width and not all backing plates are the same.

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

Thanks
After Re measuring the backing plates they are the same.
Yes I need to pull the wheels off mine to get a good measure.
I think I will just get the pumpkin out and let the rest go.
Thanks for your help.

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

Thanks for the info.
I have a 14 bolt waiting in the wing.
It is funny how this stuff happens.
I was walking thru the pick a part and this one jumped out in front of me.
I will probably just get the pumpkin out of it.
The whole thing may follow me home:)

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

Thanks CaptinFab and abig84 for the info.
I came home with just the chunk.

Here is my Numbers I have to share maybe some helpful info someone could use later.
The H072 rear axle I pulled the chuck from today was a 36/8 tooth (4.5 ratio).
It is anybody's guess if it was original.

The vin tag was Gone so No id but(from what I had to go by) it was 64-66 Chevy C-30 with 6 cyl. and sm465 with parking brake on the rear of the trans.
The main info I found out is that the axle housing would be a direct swap to my 67 cab and chassis C-30.
The measurement to the center of each spring perch is 40".
Both trucks have 2 1/2" wide springs.

From the same Pick a part 6 months ago.
There was a 71 GMC 2wd V8 Fleet-side truck (Flint plant).
I pulled the chunk from it was 32/8 tooth (4.0 ratio). this is the one I will use in my truck.

I also bought the doors from this truck. It still had the Blue I.D. sticker on the door.
In the 5th spot was an O or 0. I looked at the Vin decoder that bruceman1968 has on this site.

Attachment 1795607

This makes me think that the O was maybe for that 4:11 ratio rear chuck.
Hope this info helps someone.

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

Does anyone know what size these bolts are on the h052?

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

1/2 diameter threads. Has 13 threads per inch and is 1 3/4 inches long.
Take 3/4 wrench or socket.
1/2x13TPI and 1.75 inches long

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

Thank you very much for the timely reply, I'll head to the hardware store. I took mine out to inspect and have no clue where I put them 😅

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

They also have lockwashers.

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

Okay, I've got the bolts in everything tourqed in spec, including the rear cover axles and pinion. But now I cant move the pinion by hand, the wheels run opposite of each other. Any ideas?

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

Did it have a stack of shims between the Pinion housing and Rear-end case?

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

If it did I was unaware, I removed the 5 bolts then tried to remove the pinion nut, it's very stuck so I left it. 2 years later came back and that's where I'm at. Everything moved by hand twisting the pinion before I tightened the 5 bolts down. Now the wheels will move but the pinion I cant move all but a couple inches then I stops.

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

Attachment 1809813

I have 3 of these Rear Chucks.
I have not disassembly any of them except for removing that one bolt to get a measurement.
I hope I can help you with this problem.
Are you familiar with how to set the ring and pinion back lash with Persion blue?

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

I'm very under educated when it comes to anything pinion, I can pull axles and set a new diff in but that's about it.

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

That is why this Forum is so good.
I will try to find the link you need to look at.
The Adjustment for this issue is right behind the pinion bolts on the drivers side(I Think}.
But let me look at my spare chucks tomorrow and see.
Maybe some one that has Rebuilt one of these will chime in.
I like this type of rear end because once you get the chuck set up it is a push in and bolt up deal.

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

I hope so, it has been very bullet proof untill my gorilla hands got ahold of it 😅 I'll hang tight for a while and maybe try and stab the motor in the meantime. Thanks for all your help, it really is the coolest thing to have so many like minded people in one spot. Cheers.

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

Here is only a Example link just to give you something to think about.

http://67-72chevytrucks.com/vboard/s...inion+backlash

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

Thank you, I'll start reading up.

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

step 8 may be of assistance here as well as lots of useful HO52/HO72 info..

https://www.stovebolt.com/techtips/a...Ton%20Upgrade/

I think you're referencing the load bolt on the exterior that is only on HO72 I believe..


I have a non locker HO52 in my K20 burb and a donor HO72 locker I plan to swap in..

both 4.10 ratio so planning to just swap third members and move on..

sorry but that's about all I've got, good luck!

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

This is the link I was looking for.
http://67-72chevytrucks.com/vboard/s...d.php?t=714492
Hope this helps to give you ideas.
Search the Web for ring and pinion depth.
That sounds to be your issue.

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

I read somewhere a while ago that the ho52s, don't have a crush sleeve in that case how do I go about tourqing the pinion nut down after I take it apart. Just throw 100ft lbs at it?

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

I haven't had one apart myself but the general consensus seems to be that.. I'm sure there's a bearing preload procedure for it though.. I did stumble across this site that sells parts for these and seems that only shims are required for pinion depth, no crush sleeve for preload..

http://www.quad4x4.com/catalog/categ...-1972#cat_2846

if it were me, I'd consult Anaheim gear [local to me] and either pay a few bucks for a professional bench setup or ask for some free advice and drop off a couple of twelvers..

there's more info out there including factory repair manuals as well that could be consulted for proper procedures.. I just haven't gone that far since both of mine are in good order not requiring disassembly as far as I can tell at this point..

pirate4x4.com has a lot of threads on the subject but tread carefully there.. loosely moderated and you'll have to sort the fly poop from the pepper..

if I turn up any info I'll gladly share, good luck!

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

I've pulled the axle, I was getting tired of climbing under the truck, gets tricky at 6'2" and 285 lbs. So now I have access to both sides of the pumpkin, to check pinion depth and bearing caps ect.

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

Good choice.
This way you will also have more light on the subject.
Have you purchased any Persian blue to check your pinion depth?

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

Not yet, I've got a little bit of yard work that needs to be handled then off to the parts store!

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

So I pulled the cover and to be dumbfounded. Nothing seems out of place... no locker 😥 but both axles are spinning with the ring and pinion. But where I'm stumped is when it was under the truck, I could only move the pinion 2 inches total. When on jack stands I can spin it for ever no locking no funny business.

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

https://youtu.be/6I5kb-lUD9U

https://youtu.be/WlbrimAlmVw

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

In the second video
when you was holding the pinion and moving the ring-gear / That appears to be way to much backlash (Slop) it should only have a few thousandths (0.008 to 0.010) thousandths of an inch.

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

How do I go about correcting that?

https://youtu.be/ZoLpCK_q9ys

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

Let me get a picture of my chunk set up to check it for a Visual.
Then I will see what type of adjustment those have.

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

I don't mean to be insulting at all, so please don't take it that way. When it was on the truck, you had both wheels off the ground correct? A good distance off the ground? Assuming you did, was the ebrake on even slightly? Or could if have been the shoes catching? Are you absolutely certain that it was locking up when you tried rotating the pinion or was it just enough resistance that you couldn't overcome it without a bigger lever (ie, rotating the wheels). It just seems to me your looking for a problem that isn't really there. I've been down that road before myself, chasing something and the answer was so obvious I couldn't see it. :D

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

None taken, I had the wheels 4 inches off the ground I think I had one of the axle nuts to tight and was just enough resistance to cause the problem, the e brake hasn't been working for years😅

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

Attachment 1810386

Attachment 1810387

Attachment 1810388

Attachment 1810389
1st pic is adjustment collar. Red paint is collar yellow is the lock for the collar.
2nd and 3rd pics are indicator and magnetic base to check backlash.
These can be purchased at harbor freight.
4th is adjustment collar for other side.

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

Okay that's what I'd thought, now here is the million dollar question. I can hope the pinion still and then rock the ring gear, when the pinion is held still there is little to no movement between the 2 now if I let go of the pinion it move the ring gear and axles all together. So I'm betting the back lash is probably where it needs to be.

I haven't moved the adjustment lock tabs at all sense I've owned the truck.

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

Yes .Hold the Pinion still. Then move the carrier back and forth. There should be about (0.010 to 0.030") best I remember.
The Pinion housing was removed thou(right).
If so this could change things.

Pinion depth and the ring gear pressure against the ring go hand in hand.
Maybe you got lucky and the pinion is put back just like it came out.