Hi Guys
My rear axle seals ony 71 F100 are leaking.
My mechanic in town says that they need to be changed, along with the wheel bearings - then we can take care of the rear brakes.
For any of you who have been down this road.....Where is the best place to get quality seals & bearings?
Please be as specific as possible, as I know nothing about this end of the truck.
Oh, it's a 9" rear end. 28 Spline (I'm pretty sure).

Thanks,
Bob

 

Pretty sure doesn't cut it.

1971/72 F100 could have a 9" with 28 spline axle shafts or a 9" w/a 9 3/8" ring gear, 31 spline axle shafts and Traction-Lok.

9 vs 9 3/8: The bearings and seals are not the same.

AXLE code stamped on the 2nd line-far right of the Warranty Plate, located on the left door face below the latch.

Post what it is.

 

Timken or SKF bearings and seals.

 

2X Bill.
3.3M axle.....1 17/32" I.D. bearing KIT...D8AZ1225C.
3.6M axle......1 5/8" I.D. bearing kit...DOTZ1225A.

 

Which brings up something else. The "industry" number off an old bearing will help Bill or I also.

 

BIN = Bearing Industry Number, what auto parts stores and bearing shops go by.

All the OP has to do to get the correct parts...is whiz down to the auto parts store with the BIN that is stamped on the axle bearing.

DOTZ-1225-A 9 3/8" axle bearing is BIN 1580

There are multiple different BIN's for the 9" bearing as Ford changed the part number (so what else is new?) multiple times.

 

Dollars to donuts says the likelihood of the rear end in your truck is a 9-inch.

A 9-3/8" rear end is very easy to distinguish from a 9-inch rear without taking anything loose from the rear end assembly to identify it. Simply look at the face of the 3rd member. If it's a 9-3/8" rear, the 3rd member will have (2) widely spaced vertical ribs running up the front of the 3rd member. The main determining feature is the top horizontal rib. It will curve downward on the end, on the left side.

Photo of a 9-3/8" 3rd member.



A common C7AW 9-inch 3rd member will have a single vertical rib and (3) main horizontal ribs with no downward curvature of the horizontal ribs.


Common 3rd member case you will find.



Chances are probably slim that the 3rd member would be a factory N-case (the ultimate Ford 9-inch 3rd member) but if so, it would look like one of these two. (These two N-cases belong to me).


Heavier duty Daytona version N-case.



A factory N-case prior to 1970 will not have the large "N" present on the casting between the two vertical ribs.

The only other Ford 9-inch 3rd member that looks somewhat similar to the N-case would be the much weaker 1957 through about 1960 WAA, WAB or WAR gray iron cases. They are notorious for the driving pinion housing breaking away from the 3rd member casting, under high torque or horsepower loads.

Third Member Cases

If your truck has a 9-inch rear end, the rear axle seals (O'Reilly part number) is MPS 51098.

Pinion seal p/n is National 7044NA.

3rd member-to-housing gasket is Fel-Pro p/n RDS55074.

 

Hi Guys,

Thanks so much for the quality input.
My rear end is definitely a 9".
It is a 28 Spline.
It is a "C7" rear end.

Now for the unusual way I came about this information......
A long time ago, somebody told me to go look on the door.
I did - and checked the numbers. It showed that it was a 3.5 gear ratio, which was perfect for what I wanted (a work truck).

Then, I looked at the tag on the rear end (it wasn't accurate) - it showed 3.5 as well. And I saw a big "N" on the housing, as well. I was really psyched - this was perfect!

Then, Mr. Reality came around - a friend who helped me with my truck, and eats, drinks, and sleeps Ford Bumpsides and FE Engines looked at it......
The "N" is rubbery and not real. It is definitely not the original rear end, and not a 3.5 ratio. He figures it is about a 2.73 (more of a Highway Gear).
He actually has a nice 3.25 rear end that I may get down the road, but at the moment, I just want to stop the leaking, so I can get the rear brakes done, and be able to pull my trailer safely.

I wanna do the seals, wheel bearings, and eventually the rear brakes. Thanks for any help.

Bob

 

With luck your axles will come out easily. Not always the case. If so replacing those seals are pretty easy. I had new bearings pressed on to my axles by a local shop.
I would put some anti-seize goop where the bearing rides in the axle housing. If you want to see a nightmare related an axle not coming out easily, you might check out some of my posts. A lesson in how not to do some things. Also, make sure there is not too much rear end oil in the differential.

 

Ford 9-inch rear end will require 2-1/2 bottles of gear oil.

 

oops, thought I was starting a new subject.

 

C7 = Dana 60 / 3.54-1 / Limited Slip / 5,200 lbs. Rear Axle Capacity.

Since you have an F100 and Dana 60's were only installed in F250's, either you copied down the wrong code or the door has been replaced.

AXLE code stamped on the Warranty Plate, which is located on the left door face below the latch. People replaced damaged left doors with used doors.

99.9% of the time, they failed to install the original Warranty Plates on the replaced doors.

 

Hi Guys,

What I meant to say when I said "C7" was that it was a "C7AW". It looks exactly like the one shown in the post above. My friend (Ford Truck Expert) said it is definitely a C7AW. But, he was just saying, C7. He said it was probably the next best thing to the "N" rear end for towing/hauling.

So, that's the type of rear axle seals, and wheel bearings I'll be looking for. I sorta want to get the better ones, and not some el cheapos. The mechanic said there is quite a bit of difference, and ya don't want to have to do this again right away.

Thank You,
Bob

 

Post 2: I asked you to post the AXLE code stamped on the Warranty Plate, so when you posted C7, I assumed it was the code.

 

Don't forget to make sure the vent is clear.