rear big bearing seals

[RICH MUISE]

I need to replace the big bearing seals on my differential. I don't remember what bolt pattern I used.......does it make a difference, or are the seals the same regardless of bolt pattern? Anyone got a part number?
My car passed 22 of the 23 inspection points for the NSRA "safety 23" sticker, emergency brake being the holdout. We tried to adjust when my car was on the lift having the rack replaced, but it wouldn't hold. My mechanic noticed the rear seals were leaking and thinks maybe it got on the brake pads. There is a possibility I have an issue with my rear left caliper, so I'm going to order a new set and have them replaced along with new pads and the seals.

[gasman826]

Early Big and Late Big(Torino) bearings are the same size ID and OD.  Small bearings are the same ID.  Early Big and Small Bearings use the same seal.  Late Big are a one piece seal and bearing.  If leaking, the entire bearing/seal needs to be changed.  I have changed all mine to Early Big.  If the seal leaks, easy and cheap repair.  I only use Moser or Strange bearings(Early or Late).  I have NOT had a leak or bearing failure since changing back to the old style.  A good quality Late Big is fairly reliable but tends to leak if disturbed.  I like to change gear ratios without having to change axle bearings each time.  Early and Late bearings are interchangeable.

Early Big Bearing hold down plate bolts are 1/2"
Late Big Bearing hold down plate bolts are 3/8"

[RICH MUISE]

Thanks for the info Gary. I guess I need to pull stuff to get to the bolt size. I wish I could find my invoice for the disc brake kit....that would tell me. One of these days I'm going to get all that stuff together and make a notebook.

[Ford Blue blood]

Rich keeping a note book was learned a long time ago.  I try to keep all receipts and invoices in a folder to track the parts and the cost.  It has paid off a couple of times as the mind goes south with time to help recall a part, especially with the amount of time it takes to get one built for me.....

[gasman826]

link to Small, Early, and Late bearing bolt pattern:

https://cmwraceparts.com/moser-custom-9-inch-ford-axles.php

The bolt pattern can be measured from the outside of the axle flange without disassembly.

[Rancher]

Another "notebook" guy here.
If I did keep a log I wouldn't remember where I left it. Lol

Wasn't there an easy way to ID them from the back by hardware?
One used T-bolts the other square or D head, something like that?

[gasman826]

It really doesn't matter.  A big bearing is a big bearing...they interchange.  The choice is intergraded seal or separate seal.  Separate seal must be purchased separately from the bearing.  I got a buy on eBay and have a half dozen on the shelf.

[RICH MUISE]

I went back and checked my build thread. These are the Timken (non-sealed)bearings ;
http://57fordsforever.com/smf/index.php?action=dlattach;topic=5795.0;attach=15900;image
I can't say as I've ever seen a bearing with integral seals, but these look like they're not them. The shop that built my differential obviously supplied the seals, so I won' find a part number in my records. Also, I found the info on the disc brake kit I bought from Summit, and it's for big bearing, Old Style.

[gasman826]

The bearings in the picture are Late Big bearings with the seals built in.  The Late Big is a tapered, roller bearing.  The Early is a ball bearing.

[RICH MUISE]

OK, thanks. So, if I understand correctly, if my "seals are leaking", I actually need to replace the bearings. I think I may go to the shop that redid my differential and see if he has a record on file of my PNs.

[gasman826]

Yes.  If you have the Late bearing like in the picture.

Moser 9508M are $70 a pair with rings plus the cost of seal (Chicago Rawhide Part # CR15141).  Moser Late tapered are $100 a pair and not available.  First it was shipping...now its shortages!!

Initially the price is a wash.  The savings comes with the next leak.  Right now on eBay, NORS seal is less than five bucks!

Have we beat this subject enough yet?

[RICH MUISE]

Almost. Yesterday I talked to the guy that built my diff. He got online and printed me out an info sheet (Summit) on Moser Engineering 9508T with an estimated ship date of 6/14....."will be special ordered for you". Comments?? ($70)

NORS on eBay.........never understood why one would want a nos rubber part/ part with rubber.

His computer crashed last year, has a new system, might have my info in an older computer at home.
Edit......the 9508-H is 1.771 I.D., the -T is a 1.562 I.D. Do I have to pull my 31 spline hd axles to find out what bearings I need?  If I have him do it, he'll pull the car apart, order parts, and my car will have to sit there for whatever time (weeks) it takes for the parts to come in. I'd prefer to have all the parts I need before starting if that's possible.

[gasman826]

I've had that thought too.  It's a toss up...well made old parts or crappy new parts.  I've changed out more new, failed seals than older seals.  I wouldn't use NORS if I didn't have confidence in them.  Come to think of it, I have been lucky and not changed out any NORS parts.  Knock on wood, several of my projects have NORS u-joints, ball joints, tie rod ends, idler arms, bushings, motor mounts, transmission mounts, and body mounts.  Who knows, the next time I open a 30 year old box and unwrap the paper, the seal might just crumble in my fingers.

[RICH MUISE]

I added an edit ^^^^^^^^while you were typing.

[gasman826]

I stay with the OE (stock) axle diameter (1.531) which means Moser 9508B or 9508M part numbers.  The Moser 9508H and 9508T are for some other axle that I am not familiar.  They could be 33,35 or 40 spline axles.  You need to 1) guess 2) find your axle order sheet or documentation, 3) pull an axle and measure, or 4) buy all the sizes and return what you don't use.  Without an axle or bearing part number, my best guess would be that your 31 spline axles are the standard 1.531" diameter.  There would be no justification in the world for your application to have an expensive, exotic axle bearing diameter.  I do understand from tech's side and your side that you don't want your car hanging on his hoist waiting a month for a bearing.  But, it would take longer to get your car set on the hoist than it would to pull an axle, measure it and put it back together.  If you need, I have a spare bearing on the shelf...USPS Priority 2 Day $8.50.  Replace it or return it.