1950 sedan rear end help

R

rockabilly

Junior Member
Hello everyone!

I'm getting close to being able to finally drop the car down and take it for a spin. Over the last few months working on the weekends I completed a 289/C4 swap, full rewire of the car, LED lights, new gauge cluster, all sending units, new clock, welded the floor patch panels, made a new trans tunnel, POR-15 everything, sound deadening throughout the whole car, new door panels, carpet, exhaust, new driveshaft, and about 500 other things I'm forgetting.

One of the items I still need to handle is the pinion seal on the rear third member. It was leaking pretty good. I got a new seal, but it looks like the only way I can replace it is by completely removing the third member from the rear end, removing the entire differential gearset, removing the pinion gear and punching the seal out from the inside. All of that seems pretty straight forward, but I'm worried about ruining the front/rear pinion bearings and the carrier bearings. I went ahead and found a NOS pinion bearing and race cup just in case, but I don't see any sort of crush washer and I don't want to set too much/little preload if I have to replace the bearing. I have the third member on my workbench, new pinion seal, new pinion bearing/cup, new axle seals, new pumpkin seal and plenty of RTV/fluid.

Any tips on this so I can get it right the first time? This is the first time working on a rear end of this style.



Thanks in advance!
 

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rockabilly said:
Hello everyone!

I'm getting close to being able to finally drop the car down and take it for a spin. Over the last few months working on the weekends I completed a 289/C4 swap, full rewire of the car, LED lights, new gauge cluster, all sending units, new clock, welded the floor patch panels, made a new trans tunnel, POR-15 everything, sound deadening throughout the whole car, new door panels, carpet, exhaust, new driveshaft, and about 500 other things I'm forgetting.

One of the items I still need to handle is the pinion seal on the rear third member. It was leaking pretty good. I got a new seal, but it looks like the only way I can replace it is by completely removing the third member from the rear end, removing the entire differential gearset, removing the pinion gear and punching the seal out from the inside. All of that seems pretty straight forward, but I'm worried about ruining the front/rear pinion bearings and the carrier bearings. I went ahead and found a NOS pinion bearing and race cup just in case, but I don't see any sort of crush washer and I don't want to set too much/little preload if I have to replace the bearing. I have the third member on my workbench, new pinion seal, new pinion bearing/cup, new axle seals, new pumpkin seal and plenty of RTV/fluid.

Any tips on this so I can get it right the first time? This is the first time working on a rear end of this style.

Thanks in advance!
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Check page 105 of the manual re pinion seal replacement; it can be done without removing the diff. The manual suggests using a special tool to remove the seal but any sort of tool/tools to gouge it out should work?
 
Don, thank you for referencing page 105, as I have that manual in front of me currently. The problem is that tool just doesn't exist anymore. I have a slide hammer puller, but the gap between the pinion and the inner wall of the seal is incredibly tight to get a tool between. I can completely understand why they had to come up with a special tool Ha!

I have the assembled third member on my workbench and when I get home I'm going to see if there is any possible way to get the seal out without taking the entire third member apart. The classic pick/chisel/flathead screwdriver routine doesn't seem like it will get the seal out, but I'll be sure to give it a try before I rip it all down.

Just trying to get some troubleshooting/proactive advice in case it goes that way, which I have a feeling it will.
 
The manual seems to call out several specialized tools and stock parts which don't seem to exist anymore, at least as far as my internet digging has found. That is why I have brought these questions forward hoping that there are some tricks to getting it done in 2024.
 
Millions of these cars were sold so I'm sure someone else will run into replacing the pinion seal on a Shoebox and not have the incredibly specialized Ford brand puller designed specifically for this rear end. Here is what I did and it went smooth as butter:

Pull both axle shafts out of the rear end, remove third member from rear end and get it on a table. Mark where your adjusting nuts are currently set (these are the large bowl shaped pieces with holes every 3/8" or so mounted outside of the carrier bearings) so you can put them back where they were previously.

Remove the two bearing caps that hold the adjusting nuts and carrier bearings in place. Make sure to mark which side is which and set them to the side. The adjusting nuts and bearing caps might need some lights taps with a soft hammer to separate them from the third member case.

Once the adjusting nuts and bearing caps are loose, you can remove the entire differential as once piece. This will allow access to the pinion gear. Simply pull it out of the third member case, but pay attention to the orientation of the bearing spacer. When the pinion gear is out, you have the ability to either punch the seal out from the inside or pry it out from the outside. Clean seal seat, replace the seal and reassemble.
 

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Did this last year on my 49, without any special tools. Combination of what Tubman and Rock mentioned.

I also removed the axles to replace the bearings and seals.

I used a self tapping screw on the end of a slide hammer. It was the original Chicago
Rawhide seal, complete with leather.

Used a local bearing supplier for the bearings and seals. Also installed CR Speedi Sleeves - dang these have got expensive!

No more oil leaks is the result of all of this.
 
With how close the pinion bearing is to the seal (literally against it) I didn't want to risk drilling into it or contaminating the bearing with metal shavings or even damaging it with a self tapper. I love the idea, but those parts are getting harder and harder to get.

Honestly just taking the third member out and having it on the bench was a breeze and made it much easier to work on. It also allowed me to reseal the third member to the pumpkin, which looked to be leaking anyway, and clean out all of the nastiness from the inside of the pumpkin that doesn't make it out of the drain hole. From start to finish maybe an hour more work than trying to get the seal out of the housing with everything still in the car.
 
rockabilly said:
Millions of these cars were sold so I'm sure someone else will run into replacing the pinion seal on a Shoebox and not have the incredibly specialized Ford brand puller designed specifically for this rear end. Here is what I did and it went smooth as butter:

Pull both axle shafts out of the rear end, remove third member from rear end and get it on a table. Mark where your adjusting nuts are currently set (these are the large bowl shaped pieces with holes every 3/8" or so mounted outside of the carrier bearings) so you can put them back where they were previously.

Remove the two bearing caps that hold the adjusting nuts and carrier bearings in place. Make sure to mark which side is which and set them to the side. The adjusting nuts and bearing caps might need some lights taps with a soft hammer to separate them from the third member case.

Once the adjusting nuts and bearing caps are loose, you can remove the entire differential as once piece. This will allow access to the pinion gear. Simply pull it out of the third member case, but pay attention to the orientation of the bearing spacer. When the pinion gear is out, you have the ability to either punch the seal out from the inside or pry it out from the outside. Clean seal seat, replace the seal and reassemble.
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rockabilly be aware (you probably already are) that you will likely get oil leaking along the splines between the pinion and the yolk. RTV behind the washer and pinion nut will cure it.
 
I use a drill bit with a long wrap of masking tape as a drill stop. I put grease on the bit and old seal to catch chips. I start with two holes 180 degrees apart, the diameter of the threads lowest cross section in the valleys of the pitch. Install a slide hammer with a machine screw that will thread into the holes. Pull from side to side till it moves enough to pry on or just keep popping away till it either comes out or pulls the thread out. If the latter happens then drill more holes to keep pulling away at it. I've been using this method for many years and have never had a seal that wouldn't pull out.
 
I think a couple of holes, a slide hammer, and a sheet metal screw disturb the carrier a lot less than tearing it completely apart.
 
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