1948 Chevrolet 1 Ton Differential Rebuild Leather Oil Seals

8

87vette81big

Guest
I have in my possession a 1948 Chevrolet 1 Ton full floating axle Differential to rebuild.
Usually parts for most makes & models are not a problem for me to locate & purchase.
This rear differential was made from 1948 to 1951. Chevrolet built, not an Eaton or Rockwell unit.
A search on the internet has yielded Zero results.
I did locate a copy of an original 1948 Chevrolet truck service manual online. Made printouts.
The front & rear pinion bearings are a BARREL type roller bearing with a 1- piece center race for both bearings. The rearmost pinion bearing is a straight roller bearing like a Ford 9 inch rear uses.
I have Hyatt Part numbers to work with & possibly convert over to a Timken or SKF bearings.
The Pinion Oil Seal & full floating hub oil seals are Leather type Oil seals. No part numbers.

Does anyone have a source for the Pinion bearings, carrier bearings, Pinion Oil & Floating hub oil seals ?
For an all original 1948 Chevrolet 1 ton pickup being restored.

Its a Super stout rearend & heavy.
I thought Dana 60's were heavy.
Has to weigh over 400 lbs this 1948 Chevy 1 ton rear diff axle complete drum to drum.

Brian
 
Re: 1948 Chevrolet 1 Ton Differential Rebuild Leather Oil Se

Thanks Grumpy.
I can make some phonecalls Monday morning.
The rear differential is a model H-072.
Maybe Timken built.
Similar inside to modern GM 14-bolt.
Hypoid ring and pinion. Not spiral bevel gears as was typical in the 1940s.
Always thought hypoid gears were an Oldsmobile innovation. Looking like not so.
4-pinion spider gears. Open diff case.
5.14 gearset.

Brian
 
Re: 1948 Chevrolet 1 Ton Differential Rebuild Leather Oil Se


Looking forward to seeing how this is done. I hope you will be posting lots of pics !!!

 
Re: 1948 Chevrolet 1 Ton Differential Rebuild Leather Oil Se

Indycars said:

Looking forward to seeing how this is done. I hope you will be posting lots of pics !!!
Click to expand...

Yes I could start a new thread on this 1948 Chevrolet 1 ton Rear diff rebuild. Pretty straight forward as long as I find the correct parts to rebuild as I like to complete.
One of the oldest rear diffs I have been asked to overhaul.

If you look back to the 1930's into postwar 1940's, its very interesting to check out drivetrain technology. Much of the same is still being used today. Just more refined.
Centrifugal & roots superchargers existed & used on the exotic European & Domestic American cars.
Like the Duesenburg SSJ. I read recent a test drive done a few years back on a fully running & restored example. Had mega torque with a super flat powerband & acceleration to be admired even today.
Let alone all the wonderfull engine mechanical noises & exhaust sound shifting through the gears.

BR
 
Re: 1948 Chevrolet 1 Ton Differential Rebuild Leather Oil Se









































 
Re: 1948 Chevrolet 1 Ton Differential Rebuild Leather Oil Se


Is the pattern supposed to be that close to the toe of the gear tooth?

 
Re: 1948 Chevrolet 1 Ton Differential Rebuild Leather Oil Se

Indycars said:

Is the pattern supposed to be that close to the toe of the gear tooth?
Click to expand...
Lightly loaded Rick.
Closed up backlash to .008,
Was .020.
Used gear. Can't get new nomore.
Will lap in. Live.
Going to power load
Made a diff dyno.
48Vdc Aircraft starter. Worm gear drive.
Will have full pattern.
Install drum brakes tonight.
l
 
Re: 1948 Chevrolet 1 Ton Differential Rebuild Leather Oil Se

Child's & Albert Vintage 48Vdc Aircraft Top Fuel Starter.
Upper Blower Pulley drive.
Big Monster. 15-20 estimated HP. Torqueat least 500 Ft/lbs.
Radial piston engine starter motor original. 21 cylinder.
Post more pics tonighr Rick. @work now.
 
Re: 1948 Chevrolet 1 Ton Differential Rebuild Leather Oil Se

I have here The 44 Magnum S&W - Desert Eagle 44 of Racecar Top Fuel Dragster - Funny Car of Electric Starter Motors.
Its Heavy. Around 80 lbs +.
12 VDC battery sufficient for most Differential Dyno Needs.
Spins crazy fast at 48 VDC.
From 1968-71 Drag Racing era best I can tell. Very rare today.
Swap meet find around 12 years ago. Drag racing- Top Fuel swap meet.
000 Welding cables to carry High Amps.
Its Pretty KOOL the C&A Top Fuel Starter to have around.

















































 
Re: 1948 Chevrolet 1 Ton Differential Rebuild Leather Oil Se

I did some more power loaded testing this evening.
Decided the pinion setting was off .
How much off I am not sure.
Pinion is set too deep into Ring Gear.
Have to move pinion towards the front & out of mesh.
Making the call on how much to remove or add shims on pinion varies in the particular hypoid helix cut into gearset and pinion offset present from ring gear centerline.
Any musclecar or popular race car rear I can predicy by studying pattern present & experience learned from other differrntial builds.
Entire different animal I am working on .
I can't use my pinion depth gauge. No published checking or mounting distance.
I do know I have a Nominal or "0" cut gearset.
Unique pinion depth shims present. No longer made for this 1948 Chevy 1ton H072 rear diff.
Pinion depth shims located in a machined register in 3rd member center section & sandwiched between special 1 piece bearing race on rear taper bearing cone side.
Like a 1957-64 Pontiac Olds 9.300 & Dana 60 Rear diffs.
4.300 OD of shims. 4.010 ID. .150 diametric cross section.
.015 & .018 thick shims. .033 " inch total pinion depth shim pack.
Must ADD(Opposite of Chevy 12&10 bolt rear) to move pinion out of gearmesh
Going to use my Granite surface plate table to measure dead accurate what I need with a digital height guage. Check old bearings stack hieght & new bearing stack heights .
Measure each. Subtract. Know how much difference. present.
Shims a problem.
Have a plan.
 
Re: 1948 Chevrolet 1 Ton Differential Rebuild Leather Oil Se

I did some more online searching.
Keyvwords 1948 Chevrolet 1ton H072.
Came up with a hit.
Randy's Ring &Pinion.
He shows a listing for a. rebuild kit.
1960-72.
GM 3/4 & 1 TON & Suburban.
Ball bearing equipped or 2 tapered roller bearing pinion setup.
Seems they used variations of this type of rear differential for some time.
Early H072 diffs use a unique 1-piece tapered roller bearing race as I am working on & barrel rollerbearings everywhere else.
I called.
Found me pinion depth shims.
Different style than stock. They install between pinion gear head & Rear tapered rollerbearing.
I have to carefully remove that bearing without destroying.
Use my Snap On bearing seperator plate & A press.
Matched bearing set.
PIA.



Farmer that owns wants yesterday of course.
 
Re: 1948 Chevrolet 1 Ton Differential Rebuild Leather Oil Se

Just for Reference of how large this 1948 CHEVY 1 TON REAR DIFFERENTIAL IS,

H072 Has a 12-1/8 " - 12.125" inch ring gear.
Threaded Ring gear brass tipped load adjust bolt too.
 
Re: 1948 Chevrolet 1 Ton Differential Rebuild Leather Oil Se

87vette81big said:
I did some more online searching.
Keyvwords 1948 Chevrolet 1ton H072.
Came up with a hit.
Randy's Ring &Pinion.
He shows a listing for a. rebuild kit.
1960-72.
GM 3/4 & 1 TON & Suburban.
Ball bearing equipped or 2 tapered roller bearing pinion setup.
Seems they used variations of this type of rear differential for some time.
Early H072 diffs use a unique 1-piece tapered roller bearing race as I am working on & barrel roller bearings everywhere else.
Click to expand...

Brian when I search on "H072 Differential" I get lots of hits, but it's always for the Yukon Master Kit. Amazon seem to be the cheapest price at $588.77, but it actually ships from Drive Train Parts Las Vegas.

http://www.drivetrainpartslasvegas.com/ ... ho72-b.htm
http://www.amazon.com/dp/B0078U8CIW
http://www.gearsunlimited.net/bearing-k ... load-bolt/
http://www.drivetrainsuperstore.com/pro ... KGMHO72-A/


 
Re: 1948 Chevrolet 1 Ton Differential Rebuild Leather Oil Se

Thanks for looking also Rick.
Bearings for this 1948 Chevy H072 are different from the listed 1960-72 Yukon H072 rear master rebuild kit sold current.
I found all by individual part numbers.

OLD CAR BEARING IN NORTH CAROLINA HAD & SOURCED OUT.
SUPPLIED A KIT.
THE SPECIAL PINION BEARING ASSEMBLY COSTED $500 ALONE !!!!
CAN'T GOOF UP REMOVING PRESSED ON B :? EARING.
:shock:

I caught the Tech guy at Yukon gear in Washington state Friday late.
Stayed late and found a shim kit that will work.
Have to call back Monday morning & Order.
All sales people left for the weekend already.

Make it work.
 
Re: 1948 Chevrolet 1 Ton Differential Rebuild Leather Oil Se

The Yukoon Gear Tech guy checked for current availabilty of the 1960-72 GM H072 Master Rebuild kit.
There are none anywhere.
They don't have either.
No correct bearings in stock to build a kit.
No one has ever purchased the H072 Yukon gear kit.
Just on the Net listed.
Funny......

Have the pinion depth shims in stock I nee
d though.
Big assortment. Won't break the bank account either.

Good Mechanic has to improvise.
Very versed there too.
 
Re: 1948 Chevrolet 1 Ton Differential Rebuild Leather Oil Se


Brian I called Precision Machine where I had all my work done on my trans, since I know he has alot of NOS for 60 something vehicles. He referred me to Steve Davis, so I called him. He said he could order individual pieces and he might have some new parts including a ring & pinion gear. He has been building rear ends since 1979.

Since I couldn't talk intelligently about what you needed, I said I would give you his number. I asked about his hours and he answers the phone anytime.

So you might try him......Steve Davis at 405-232-1972

 
Re: 1948 Chevrolet 1 Ton Differential Rebuild Leather Oil Se

Thank you Rick.
Will call Monday.
If Steve has the original style 1948 H072 pinion depth shims I would prefer them instead.
Sizes OEM produced and service was .012 .015, .018, &
.021".
I think the Ring & pinion Gearset are Ok.
No scoring or surface blemishes.
Just super light surface corrosion from sitting unused for 50 some years.
Had a broken axle shaft that disabled the truck.
Side gears and 4 pinion gears unscathed.
Owner supplied a used replacement axle shaft.

The entire pinion gear & bearings assembly slides otut the front of 3rd member.
I was able to leave axle shafts, 3rd member attached to banjo housing, Ring gear and carrier intact. Tapped the pinion gear out with a long brass drift on end of pinion.
Backed off carrier ring adjusters. Had just enough room with my Snap On carrier spanner nut diff wrench.
No welded cover. Bolts on. Ingenous & throughal engineering in this ancient 1948 H072 Rearend.
Never seen such high quality in any stock rearend diff.
Unbelievable for 1948.
Housing is precision cast steel. Smooth inside & outside.1/4 inch thick.
All welding is Heliarc stick .
Looks like TIG welded.
Like Bob here welded it. Like your T bucket crossmember you both built. ;)
Take more pics this time around assembling.
Owner was calling & texting me every 1/2 hour.
Driving me nuts.
He has no choice but wait now.........
 
Re: 1948 Chevrolet 1 Ton Differential Rebuild Leather Oil Se

Appreciate your help Rick.

Brian
 
Re: 1948 Chevrolet 1 Ton Differential Rebuild Leather Oil Se

No dice on finding the correct pinion depth shims for the '48 Chevy rear diff from your friend Steve in Oregon .
He thought I was local.
Had to explain I was calling from Illinois.
Managed to remove the pressed on Rear tapered pinion bearing.
No damage done.
Hand filed the Snap On bearing seperator plate inside edges to a Razor sharp edges.
Made the task easier. Nerve racking $500 bearing assembly & long obselete.
Yukon gear for shims now.

BR
 
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