Diff pinion seals

[Apis Mellifera]

Any pitfalls/tricks to replacing the pinion oil seals with the diffs in situ?

[KevinNY]

Some diffs have a removeable pinion seal housing which makes the swap a piece of cake. Look for 6, 7/16" bolts on the front of your 3rd.

[Sputnicker]

I just did this in my Series II. Assuming you have the standard Rover differential, there is a removable housing that's already been described. To get that off, you first have to remove the driveshaft flange, which requires removing the large nut (with cotter pin) that holds it on the pinion shaft. This large nut needs to be torqued to 85 ft/lbs upon reassembly. There is also a gasket between the seal housing and the differential case. The improved seal I got from our hosts had two lips on the ID - one on either side (the original was a metal-cased rawhide seal with one lip). The improved seal also has an additional small rubber lip on the outside diameter of the seal, which gets pushed into the bore of the housing (providing a better seal between the outside of the seal and the housing). You need to be sure you press the seal into the housing until the seal bottoms out in the bore. The new seal was expensive ($15), but it looks like a big improvement over the original (which has always leaked on mine). Be careful not to lose any of those 7/16 bolts - they have BSA threads and smaller than normal heads and would be difficult to replace.

[kevin-ct]

Remember to look for a worn grove on the flange. If there is one you will need a new flange or a speedy sleeve from the host

[KevinNY]

The flange is not that expensive and a good idea to replace considering the age of your original. That way the new seal is running on a new smooth surface.

[kevin-ct]

The flange is not that expensive and a good idea to replace considering the age of your original. That way the new seal is running on a new smooth surface.

Kevin, are you heading up to GF next weekend? if you need any parts from Paul, I can bring them with me.

Kevin

[KevinNY]

I'm good thanks. May head over for a few hours on Saturday after I get my PS leak fixed.

[Apis Mellifera]

I just did this in my Series II. Assuming you have the standard Rover differential, there is a removable housing that's already been described.

I'm guessing this feature was deleted for the SIII. This is what I'm dealing with:

[jac04]

^^ Correct. You will need to pry the old seal out after removing the pinion flange. It's kind of a PITA. I did both on my SIII, and found that I needed to replace one of the pinion flanges.
The only tricky part is getting the mud shield back in the correct position if you are replacing a flange.

[Apis Mellifera]

I finally got the rear pinion seal replaced today. I was expecting the pinion nut to be difficult to remove, but when I removed the driveshaft, I found the nut loose. Loose as in I could flip the nut and it would spin loose or tight. The cotter pin was still in place so I'm curious what could wear enough the loosen the nut. The seal was the original leather part so I don't think the PO replaced it and didn't torque the nut.

Any ideas?

The good news is the test drive after reassembly was a success. No more leaking oil and the growl from the back is mysteriously gone...

[jac04]

I found the same thing with the loose nut(s) on mine as well. I just torqued to spec at re-assembly.