So I'm replacing a leaky axle seal on my truck and I'm having a helluva time getting the new seal to go in. There's a small notch (for lack of a better word) that looks to be peened in the edge of the sealing surface (see attached pic)—is this supposed to be there? Do I need to somehow smooth it out so the new seal will go in? Thanks in advance for any help!

That divot appears to have been made while installing the wheel bearing. I can't imagine any reason you couldn't use a high speed drill motor or a Dremel tool and a small grinding wheel to smooth it out. I've also had some success with getting a seal to start in the bore by grinding a slight chamfer onto the leading edge of the seal. It won't cause any leakage because there's plenty more straight area to make a leakproof fit on the outside as the seal slides into place.
Jerry

Thanks, Jerry! I wound up using a small rattail file to smooth out the ridge in the sealing surface caused by the divot. I then took some 400 grit followed by 1000 grit sandpaper to smooth it out. I got the new seal in, but the block of wood I was using to seat the seal got a little off center and I bent the inner edge of the new seal. darn (and several other colorful words). I've ordered a new seal along with an installation tool and hope to have it all buttoned up by Tuesday or Wednesday. Here's hoping I run into no more unexpected issues!

When I installed the pinion seal in my 1 Ton, (I know it is a different size) I used a black ABS plumbing part from the hardware store.

Thanks for the suggestion, truckernix!

Finally got everything buttoned back up! I filed down the ridge on the sealing surface and got the (second) new seal installed with the help of the seal installation tool I bought (always helps to have the right tools). Got the new brake shoes adjusted and also lubed the rear spring shackles while I was there. Took the truck for a test drive and everything seemed to be working A-OK. Now I wait to see if the new seal stopped my leak. Thanks again for the help here!

I've driven my truck once since getting the new axle seal installed, about four or five miles (that was Wednesday). I noticed yesterday and again this morning a tiny but of gear oil on the outside lip of the bottom of the rim yesterday morning and again this morning. It's not enough to drip down the tire and puddle like before I replaced the old seal, but so far just enough to get your finger wet. I did inspect the axle and found no issues on the bearing/seal surface that would lead me to believe it would leak after the new seal was installed. I was hoping someone may have some suggestions on what to try next. Thank you in advance!!

You may need to put a light coat of RTV on the outer edge of the seal, with the divot in the surface it may be just enough to leak. You also might want to polish the axle surface where the seal rides, it may have a slight burr or be worn from the seal riding on it for years. I once used a ready sleeve on an axle to repair where the seal had ridden, the trick was finding one the would fit. It took the aid the machine shop to locate the proper diameter sleeve (Ford 390 harmonic balancer in that case).

Thanks, @TUTS 59! I'm going to keep an eye on it and see if the leak continues. I'm also going to check the axle vent tube and ensure its not plugged up. If I have to pull it apart again, I'll definitely keep your recommendations in mind.

The seals I found for my 59 Apache fit so tight when I tapped them in with a seal driving tool, it peeled the green paint off the outside of them. I was worried the new style seals were not as thick as the original ones. but they are working just fine. So, if your axle is leaking on the side with the divet I'd go with what TUTS 59 said above. Put a light coating of RTV around the outer edge of the seal. Spray solvent on it and make sure its not leaking sitting there static, apply the RTV and let it dry overnite before driving it. I've seen that fix a few in the past.

Good luck!