Rear Differential Model Identification

[Commander 927]

Someone in my 67 Monaco's past installed a Mopar 8.25 rear end. It is the correct width and it doesn't appear anything was relocated. They also added air shocks. It will be plenty strong for what I'm doing so I'm leaving it. I need someone to tell me how to ID what vehicle the rear end originally came in so I can order brake shoes, wheel cylinders, etc. I may need to order additional parts in the future because I'm keeping the car forever. Thanks in advance.

 

[Omni]

Good Afternoon

Not a three gauge set-up, but here is where/how I mounted two gauges on a '65 Newport w/add-on A/C.

I have since squared off and shaved down the mounting pad by 3/8 "
Omni

 

[Big_John]

Someone in my 67 Monaco's past installed a Mopar 8.25 rear end. It is the correct width and it doesn't appear anything was relocated. They also added air shocks. It will be plenty strong for what I'm doing so I'm leaving it. I need someone to tell me how to ID what vehicle the rear end originally came in so I can order brake shoes, wheel cylinders, etc. I may need to order additional parts in the future because I'm keeping the car forever. Thanks in advance.

The best thing to do is pull a drum and measure. The rear might have been swapped, but I believe the backing plates will interchange. For example, if I were swapping a rear, and the existing brakes were in good shape, I'd disconnect the backing plates and swap them (with the brakes etc. intact) to the new rear.

Mopar brakes are kinda standard in those years and can be bought by comparing sizes... But compare the sizes to what should be on there (consult your FSM) and see if they are the same.

If you don't have one, get an FSM here: MyMopar

 

[1970FuryConv]

I know from experience that brake backing plates for 8.25 and 8.75 interchange. I removed the original 8.25" from my 70 Fury and installed an 8.75". Installed the backing plates when I installed the axle shafts.

All of my fuselage cars have used 11" shoes, either 11x2" or 11x2.5"

 

[69PHOENIX]

I have Always Loved Mother Mopars Habit of Not Changing Things unless It Had to Be.
I Swapped a 65 Charger Diff into a 59 Custom Royal and was able to Swap "C" Body
11" x 2.5" Drum assemblies from a Later Model for the "B" Body 10" Assemblies.
A Simple Swap.
Regards Tony.M

 

[fury fan]

Here's a reference thread:
rear shoes for 1968 polara 2" ?

 

[70bigblockdodge]

Most likely 11×2, but measuring is best. Wheel cylinders and hardware are not always specific to one size/ or width. Self adjust cables and return springs are specific, retainers, adjusters and wheel cylinders are not.

 

[fury fan]

To follow on that:
Some things are likely common due to the diameter of the brake, while others (like the coilsprings that hold the shoes on) will be specific to brake width.
Wheel cyl will differ in bore (IIRC there are only 2 choices) based on the braking balance the engineers wanted.
Meaning - if you have fat/grippy rear tires, you may be able to increase rear braking capacity without experiencing lockup.
I have 1.12 Firmfeel front T-bars (reduced nose dive) and 275-sized rear tires, so I could take advantage of more rear braking than the 11x2" the factory installed.

 

[Commander 927]

I was wondering if there was a way to identify the vehicle the rear diff came out of so I could just order brake parts, axle seals, etc. Example: 1972 Plymouth Fury. It's the same length as the original 1967 Monaco 8.75 but is 8.25. What car or truck with an 8.25 would just drop in my car like that?

 

[fury fan]

It is likely from an early 70s C-body, IIRC was introduced in 1970 behind smallblock engines.
Regardless, you'll need to know the rear brake size - part-store listings sometimes even list options that weren't available for a particular year.
And at this point, you cannot know if the brakes are original to that rearend.
Does it have finned or plain drums?

 

[Commander 927]

It is likely from an early 70s C-body, IIRC was introduced in 1970 behind smallblock engines.
Regardless, you'll need to know the rear brake size - part-store listings sometimes even list options that weren't available for a particular year.
And at this point, you cannot know if the brakes are original to that rearend.
Does it have finned or plain drums?

I will check the rear drum style and report back next time I'm at the shop to work on it.

 

[Commander 927]

I will check the rear drum style and report back next time I'm at the shop to work on it.

I will probably take photos of the wheel cylinders and measure the brake pads. I can then look up brakes for early 70's C body cars to compare and go from there.