Numbers To Identify Rear Axle

chromebumpers

solid fixture here in the forum
Staff member
Ok, so these are everyone I could find. The internet is confusing, they have 7 digit codes and 5 digit and letter mixed numbers. I need to replace the wheel cylinder but have no idea which to buy.

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B&R Racing

solid fixture here in the forum
Brian, you never let me down yet with your master mechanic brain!
The Numbers casted in the cast iron center housing have no bearing meaning at all.
You have to remove a wheel cylinder look for a part number. Take it apart and measure the piston and bore size.
 

B&R Racing

solid fixture here in the forum
I believe it's a 1971 Year GM 8-1/2" Differential in your 1968 Catalina .
And I think it's an Oldsmobile orginal application.
The axle shaft inner hub has 2 -prongs what Oldsmobile used.
Pontiac used 4-prongs .
That part was used on Oldsmobile and Pontiac Factory plants to turn machine the axle shafts in a lathe and for Hob Cut Axle spline rolling operations.
 

B&R Racing

solid fixture here in the forum
I just noticed the photo above has a number on the wheel cylinder “1102”
It's likely an Aftermarket replacement.
It could be a AC Delco, Wagner Brakes, Raybestos Brakes, some Vintage Mom and Pops small company there were lots of them in the 1950s -1970's, see that when looking at Ebay for NOS Replacement small parts like brakes.
Likely China, I don't know who made it Richard.
 

B&R Racing

solid fixture here in the forum
I found this. These are the Identifying numbers?

View attachment 16018
It's the Factory production number Unit number to identify GM Differentials.
Dana Spicer did the same with thier Differentials.
Bad now is only way to know is look at GM Service Manuals all makes and years 1971- 1977.
It's not on the internet.
High Performance Pontiac magazine covered all the numbers 30 years ago for 1964-72 Pontiac GTO.
1967-81 Firebird Trans Am.
They did a writeup on Fullsize B body like our cars 1962-1971 also but numbers very few just not known and as popular as A & F cars.
 

B&R Racing

solid fixture here in the forum
A wheel cylinder can be rebuilt also.
As long as there is no deep rust pitting inside the cast iron body bore.
Use a wheel cylinder hone to clean it up and shine get a nice cross hatch again.

It's what is coming of course.
Rebuild salvage all we can.

I rebuilt the Original drum brake wheel cylinders on the 63 Gp in past.
Was like $ 8 per cylinder rebuild kit.
 

B&R Racing

solid fixture here in the forum
Once the inner wheel cylinder ram pins are pulled out, just pry off the rubber dust boot covers.
The pistons are steel or aluminum and come out instant usually.
Sometimes you need a small pick or screwdriver to remove the Rubber seals .
Usually pop out too.
 

B&R Racing

solid fixture here in the forum
I never bothered to rebuild a wheel cylinder when it was always (until now) easy to buy new WC’s.

https://pin.it/65HmJZv

I bought a spare set of front wheel cylinder rebuild kits for the 63 Pontiac.
Looking for the Rears today yet.
My car uses 1-3/16" front bore wheel cylinders.
Rears are 1.00" bore size.
Listed in my Vintage 1963 Year Chilton's Repair Service manual.

Stinks seller will not contact you back what your Catalina Differential came out of exactly .
 
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