Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

And has anyone seen any of the unwanted 8 lug dually ho72 rears anywhere out there?? like close to N texas

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

The original lockers that were in the HO52/72 were Detroit Lockers. They are just about indestructible but some people don't like the noise they make and the wiggling when they lock and unlock when turning.

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

If you have a 72 axle then the 14 bolt No-Spin and axle shafts will swap right in without modifications. You may get lucky and find a No-Spin for the Eaton as well. The factory locker is a Detroit No-Spin (Detroit Locker) and the 14 bolt locker that fits the Eaton is the Detroit No-Spin (Detroit Locker). They are automatic .

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

I'm still a little unclear. Not a fan of Detroit lockers, so what would it take to use a ARB 14bff locker? That's when I need to switch to the 14bff axle shafts and turn .250 off the splined end? Or is it only the 14bff Detroit that works for some reason?

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

The HO72 and HO52 use a single split case for both open and NoSpin applications. The NoSpin simply replaces the spider assembly in an open unit and was often dealer installed. Most differentials like the ARB have a dedicated case that to my knowledge have never been made to fit the Eaton HO72/HO52 series. A 14-bolt replacement carrier will not fit a HO52/HO72 series chuck.

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

Tim posted a picture of the detroit locker. Here is a 14 bolt ARB locker. Like Tim says, it has a dedicated case. If you don't want to have to hassle with machining .250 off the axleshafts (which you dont have to with the detroit) you wont want to even consider retrofitting a 14 bolt ARB to the Eaton. If you search the pirate there is a picture of one machine shop that fit an ARB to a Eaton. You have to machine the carrier bearing surfaces down and in toward CL and machine a new ring gear surface, then new holes for the eaton ring gear since they are completely different from the 14 bolt.

http://cdn3.volusion.com/rykce.hvsnw...jpg?1388663053

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

If swapping a 14bolt to replace a HO52 do you have to lengthen/shorten the drive shaft?

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

Here are the few pictures I was able to save of the ARB machined to fit an Eaton. I have been keeping an eye out for a deal on a used 14 bolt ARB to bugger up :dohh: Anyone know if the ring gear is different between the bearing types? Could I use the ring gear from a ball bearing setup with the tapered bearing style pinion?

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

I have a ball bearing type and a roller type, both 4.10s that I am about to tear into. I will also have some pinion yoke and flange info coming. Thanks for posting the picture of the 2 machined ARB. For the longest time I have been scratching my head trying to figure out the ring gear mounting for that

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

Sorry for the ignorance, and for reviving an old thread, but if people use the heavy duty rear ends like Eaton HO52 with 4.56 gears for hot rods or drag racers, and they use transmissions like TH350s, why the heck is my 71 K20 Suburban so slow? Is it just that the 350 engine can't spin the gears fast enough? Is it just the weight? If I put a 500hp engine in it, will it then 'go fast' with little other modification? (Not that I would. I am just trying to learn how it all works together.) Thanks for any insight! - Marc

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

Possibly a combination of weight and differential design? I know the ford 9" eats HP due to the pinion offset. Maybe the Eaton is the same? Also bigger gears and axleshfts and tires to spin.

If I am wrong in any of this I will be sure to edit my post.

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

There's more to your answer than can fit here. When you say "fast" do you mean top speed or 0-60 times. Research total drive ratios to help explain it. It's a combination of trans. ratios, diff. ratios and tire size. Then there's the engine. Is it build to develop torque or horsepower and where in the rpm curve?

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

I am considering rebuilding an HO72 in my '70 one ton or swapping a 14bff. I would prefer to rebuild the HO72 since it has a reputation for being one tuff system so making it new again should mean that I'll never have to do it again.

I do not know if the HO has a ball bearing or tapered at the pinion and I'm not certain how to verify that before ordering a pinion bearing.

From what I have seen though, the parts dealers are sure the HO72 parts are made of gold.

So I have a couple questions.

First, is it worth it to rebuild the HO72 and is there any one place to get all the parts (including R&P)---Don't want to order some parts then discover the others are no longer available

Is there a way to verify the pinion bearing (ball or taper) without a complete disassemble?

My truck is a cab/chassis model w/leafs, which if I am not mistaken, means that if I go with a 14bff, I would have to get a short setup as opposed to the pick-up truck axle. Can the 14 bolt swap be done without a bunch of cutting/welding or parts interchange?

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

Not positive but I think if the dropout has the pinion load bolt on the drivers side it is the tapered bearing. No new r&p are available so used is your only option. I believe most bearings are still available but as you have found are VERY expensive.

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

I would just switch to either a 14 bolt or a Dana 70. It isn't a big deal to move the spring perches. Either one of those is just as tough as the Eaton if not more.

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

Yeah, I've been looking over the options and the 14 bff makes a lot more sense.

If the leaf perches are the biggest problem then that's not really big deal.
Since I'm dealing with a cab and chassis dually one ton, intuitively that's the axle set-up I suppose would make the easiest swap. I know that some are full float and some semi float. Just don't know for certain that the one ton axles are strictly a full or semi float. I would prefer to maintain full float.

Thank you for the advise

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

just read this great help. i bought a IH pickup htat has an eaton ho (52 or 72) and was wondering how well these held up and how reliable they are

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

Much thanks Cap'n. I have recently acquired a 14 bolt ff. It's a bulky beast with 373 r&p and I believe the carrier is a gov-lock type. I was told it came from a g30 van. I am having a bit of difficulty identifying the year (if it is significant). I believe it from a mid 80's van and probably 1985 or earlier and may have the smaller pinion bearing.

I have found numbers on the axle tube and on the differential housing case. There is a little clock like symbol which I assume indicates the month and beside that there is the number 10. I guess the number 10 is the day of the month. I'm not certain about this, its just a guess.

There is also an alpha-numeric stamp on the long tube which seems to be KSRG 2692. The G is an uncertain character, could be a 6--can't tell.

Could someone please enlighten me as to what these characters represent and how to determine the year of this axle?

Also I suspect that since the van was longer than the swb c&c that I plan to install this axle in, then the pinion angle will be different unless I cut the spring perches and relocate them. Am I thinking about this correctly?

Advice much appreciated.

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

I would imagine there is a place to look up the build code on that differential, but I have no idea where to look for something that new. It sounds as though all you want to know that you don't already, is the year? If so, just pull the cover and look at the year stamped on the ring gear.

I don't think the pinion angle will be an issue but the width of this differential could be. Typically full size van differential are 3-4" wider than a pickup differential. This may or may not be an issue with your '70 C30 C&C. It will depend on what you plan to use for a bed on the truck.

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

So I speak from experience, since I do run a late 70´s G30 Van 14FF in my truck. It is correct that it is wider than the truck rear end. The WMS to WMS on the truck is 67" and the one on the van is 70". So it is exactly 3" wider and somewhat matches the 69.5" WMS to WMS on the front axle. This is the reason I changed mine out, to get rid of the wheel spacers. HOWEVER, the spring perches on the van are WAY wider than the truck. So there is no way around new spring perches or at least cutting them off and relocating them. On my K20 I already had to move them in about 2" per side, so the K30 will need them even further in.

I hope this does help. If you have any more questions, jut let me know.

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

I haven"t measured the wheel mounting surface distance difference between the van and the truck yet but the perch distance on my truck and the perch distance on the 14b I have acquired are the same. Measuring from the outside of the perch to the outside of the other, I get about 43 inches on both. My guess is the different distance of wheel mounting surfaces is in the hubs?

Also, I pulled the dif cover and the gears looks good--much better than I had hoped. A small amount of pitting on one tooth of the ring and none observable on the pinion. The diff lube looked clear (amber) and no metal residue inside the case. Backlash seem minimal---maybe .008, just a guess. But overall, it looks good.

The stamp on the ring has the 41 11 ratio, and then the number 12, then 73. I'm going to guess that the 73 is the year model of the r&p, but for its condition I am having a difficult time believing that they are the original gear set. If they had been replaced sometime in the life of the van from which this axle came, I would also guess that there are few miles on the set before the van was retired from service. I got a glance at the van the other day and I'll be going back for a closer look to see if I can determine the model year.

I was told the van has set since 98 and that would account for the pitting on the top ring gear tooth since the lube had a good long while to drain off. The carrier shows some slight pitting on the perimeter (same area as the ring gear) which cleaned up quickly with a wire brush. Aside from the slight corrosion, it looks fairly decent.

I suppose the 373's could have been replaced with a gear set made for a 73 differential and carry the 73 stamp even if the axle was 73+, up the mid 80's.
That however is just a guess because I don't have much experience at tearing these things down, at least not enough to determine if it shows appropriate wear for a 70's or 80's axle. I do know the gear set looks much better than those currently in my ho72 and the lash in it about a quarter inch. Plus the lube was burned up when I pulled the diff cover from my ho72 so I know those gears have seen their day.

Overall, the condition of the 14b is far better than the ho72. I am still perplexed though by the year stamp on the ring and the fact that the perches are the same distance apart.

Is the year stamp on the ring definitive enough to say this is certainly a 73 axle?

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

ok, so I am going to revive this as I have questions...
When I drive out the Eaton studs(mine are 9/16..1971 C20), Do I use the 14 bolt studs to put it all back together? Do I need to bore the hubs out to accept the 14 bolt studs or are they press in fit?
Also, the E-brake cable, will it hook up as original?
Thanks

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

I have a 72 chevy C-30, 292 engine with power steering, and floor shift trans. Were all of the Eaton HO-72 rear axle assembles with dual rear wheels rated for 11,000lbs
and is a rear disc brake conversion a good or bad?

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

For the rear disc, likely not worth it. I did it to mine years ago and didn't notice much difference. You also have to give up the parking brake or find one to bolt on the back of the trans. The El Dorado calipers suck with this conversion and a heavy truck.

Re: Eaton HO72/HO52 vs. 14 Bolt FF
 

The H072 rear axle was rated at a maximum of 7200 lbs with the RO5(dual rears) option and suitably rated tires.
To get a higher rated rear axle on a CS/CE30 you needed to order RPOs H022/H023 which included the 10 lug H0110 axle rated at 11,000 lbs.

Might want to review you driver's handbook or the 72 service manual's load capacity charts to see the options and tires required to achieve the specific axle and GVW ratings. Many C30 were built with a 6600 lb GVW (gross/ total vehicle weight)