Wonderful thread you guys have here. Some comments; the housing axle seals in a 9" ford do not stop diff. grease from getting to the wheel bearings. And they damn sure don't keep oil off the wheel bearings in fast cornering cars such as a cobra. The main reason they are there is to provide a vapor barrier protection for the seal surface of the wheel bearing. That rubber wheel bearing seal will rot faster without them being in there, leading to premature wheel bearing failure, in theory anyhow. That said, I'm going to give up a secret here though.
I haven't put axle seals back in ANY housing in any performance car for quite some time, years actually. They rub and give your car rolling resistance, so out they go!
Now as for your oil leak. Putting silicon around the edges of the outside of the wheel bearing will not stop that leak. The right thing to do is to pull the wheel bearing, silicone up the housing and the whole outside circumferance of the bearing, and put the whole slimmey works back into the housing. Won't leak any more I'd bet. As for wheel bearing failure, if you use new wheel bearings, those bearings will most likely out live us all if you don't put any axle seals back in. If you choose to put them back in, all you have to do is tap them in with a big socket. I usially chisel those bad boys out.
If I remember right, on 9" Fords with the big wheel bearings the seal goes out. With small bearings the seal side goes in. The seal that you see on the small bearings is really a partial seal, so I was told at Mosers years ago. The real seal is inside the bearing unseen on small bearings. Another trick is to buy the late model wheel bearings that have a rubber O ring on the outside of the wheel bearing. This O ring will butt up to the housing for a better oil seal. I can't remember if the small bearings have the O ring but off hand I'm sure they come with and without a O ring too. On some cars I've seen two O rings on wheel bearings too.
Finally, check the housing vent and make sure it's open. On almost all the cars I've ever fooled with, I'd say about 80% of the time they are closed up with dirt, esp. on high mile cars and on junk yard rear ends. If stopped up your rear end will build up pressure when hot and force oil out in places a otherwise vented rear end would not leak in. Hope this stuff makes some since to you guys.
cobrashock - veteran of the 9 inch war.:mad: :mad:

Update.....

Well, it turns out you do need seals.... apparently they don't come with the kit, atleast mine didn't even though I was suppose to get "everything you need to get the car on the road" minus the engine, tranny, driveshaft, paint, battery, wheels and tires.

Owell, they did give me the part number of the seal... that was nice of them.

Thanks for the help everyone

By the way the part number of the seal is:

Federal Mogul #473228

I ordered my car bare...so I could put it all together myself. When I ordered the rear axles and brakes, all the bearings and seals came with it. That's kinda weird that they didn't put them in for you.

Like I said Red, you'll probably need a slide hammer or something equivilent to pull the axles out. They're in there good when that bearing is pressed into the housing.

Hey Red...

You might wanna try what the other guys were saying...just pull the axles out far enough to run some sealant around the circumference of the bearing...It would save you the price of the seals...although they're probably just a couple bucks each. :-)

Hello fellas,

I've been talking with some hot rodder buddies, and they were all adamant about using seals on the 9". They said the only reason I don't have leaks yet is the oil level isn't quite high enough in the axles with the car sitting still. They will leak when you drive it. Kind of like Excalibar said, the sealed bearings are designed to keep grease in not oil out. I didn't receive any seals from SV either.

Now after reading Cobrasochs good comments, I'm not sure what to do. So, if I wait to put seals in until after I get a leak, would you say that most leaks come through the outside fit of the bearing or through the inside greased area? How would you know if the bearing was still good if oil has passed through it and maybe displaced some grease?

Very interesting topic here. Thanks for the part # Red99z.

Sydney

You guys are making this WAY too difficult. For the cost and effort in installing the seals, it's a no-brainer. Why would you purposely invite a leak when you have a choice?

If you decide not to add seals, then develop a leak, is it worth the time associated with the "do over"?

[Soapbox Off]

Blykin,

Yea, I have a slide hammer... I've pulled those axles out several time and there is not way to do it with out one... I put in new gears and a posi unit myself so I know whats involved. Its just a PITA having to take everything apart again (tire, brakes, axle). I'm just gonna go ahead and put the seals in, I'll have everything apart anyhow.

Thanks again everyone.
RED

When I was at Shell Valley I asked about the rear axle and at the time (1994) they just shortened the tubes by cutting the inside and re welding. Mine use the seals from a late 70's LTD on a 9" rear. I think they used whatever 9" rear they could find at the junkyard so seals/no seals wasn't a set thing.

We do narrow our own housings, starting with pretty much any housing we can get ahold of given that it: 1. Uses the large bearings. and 2. Has the "square shoulders" (rather than rounded butt-welded shoulders). We then put new Moser axles with new bearings in the housing. We also include a stock, rebuildable third member. We normally do not include the axle seals due to the fact that quite often they are included in a "rebuild kit" when you rebuild your third member. If however, we rebuild the third member in house, we do include the seals as part of the package.

Part # for the seals is Federal Mogul # 473228

Hope this helps!

Dana

Hi Dana,

Tim Terry here. I sent Bruce a photo yesterday. I hope the other guys in the shop liked the other stuff, too.

Our visit to Gessford was most enjoyable. George is a hoot.

I'll most likely be ready to order a kit in the Feb-Mar timeframe.

I look forward to talking with you again. Thanks for all of the hospitality during our recent visit.

TT

I noticed on some axle berings there are o-rigs If you don't have that type a little RTV will help make sure there is a axle seal in the housing before you install it

CONFUSION
 

There seems to be a lot of confusion about Ford Rear Axle/Differential Assemblies here. I have worked on countless Ford Mustangs from 1965-2003 models....I have NEVER seen a Ford 8" or Ford 9" WITHOUT a SEALED Bearing....The FORD 7.5" and Ford 8.8" seen on any 79-2003 model has a tapered roller bearing and race inside the housing with the seal on the outer most part of the housing, 8.8" and 7.5" can be converted to a SEALED bearing for racing commonly known as C-Clip eliminators....Rear ends can be identified by 8" and 9" having a drop out Center Section or 7.5" and 8.8" having a differential cover held on the back by 10 bolts....like a GM 10 or 12 bolt rear....On a Ford 8" or Ford 9" the bearing is pressed on the axle and is sealed, and is tight to the housing, bearing does not spin in housing thats why there is no race etc....seal is driven into axle tube housing and prevents gear oil from getting around the bearing causing it to spin...there is also a paper gasket that goes behind the splash shield to axle housing tube....8" Ford housings are similiar to a 9" by having a drop out center section, but have completely different components, housing doesn't have bump on back for ring gear clearence, (Except for early 9" housing had no bump either, 50's-early60's etc..) and center section looks more oval than round like a 9"...came in Early Mustangs/Falcons etc with 289, except 289 hi-po models and big blocks which came with 9" rears, unless a dealer installed it.....
It is impossible to confuse the 8" or 9" with a 8.8" or 7.5", the 8.8" and 7.5" are like a GM 10 or 12 bolt rear, never to be confused with a 9"..........
www.teamcracing.com

Brian

Looking this tread over I don't think you guys really understand how a rear end gets it's lubrication. If you understand what this about, all the other peices will fall in place.
As the gears and parts of a rear end rotates at high speed, in and out of grease, a oil mist is created inside the housing. This mist is what lubracates almost ALL the parts in your rear end, (not the ring and pinion)and believe me that mist will go everywhere inside the housing. Axle housing seals are in there to provide a place for the mist to drop out (not all of it though) into a oil liquid. Thats why some axles have a sprials cut into the axles, to help spin pump that oil back to the center section, and other "makes" pump oil towards the bearing. This depends on the design and explains why some rear ends should not be narrowed. Now some wheel bearings are open to the oil mist, some are totally sealed w/ their own grease, some have a external seal outside the bearing. WHATEVER. In the case of all the 9 inch Fords I've delt with, the bearing is open towards the rear pot and sealed to the outside, and relys on the mist for lube of the bearing. There may be however a sealed bearing out there on 9 inch Fords that I don't know of. No matter,,,,,
All is well till the rear end cools off. Then condensate gets into the oil and on a cold startup that oil mist/water mix will congeal into sledge when it cools, that is, if the rear end never gets hot enough to boil off the water out of the oil and vent it off via the housing vent. Thats why there is sledge coating inside most used rear ends too. Those bunny hops we all make builds up sludge in your rear end. (sounds perverted now doesn't it?)
Those axle seals help prevent sledge buildup in the wheel bearings and subsequent seal rot. If you don't put axle seals back in a fast cornering car such as a Cobra, live liquid hot grease
can and does get to the bearing. This does no harm to it at all. Fact is, it may even knock off some off the sledge buildup in the bearing. When a 9 inch Ford leaks oil at the housing ends, most times it's because of a rough housing end, and my silicone trick above will almost allways fix it. I've also fixed or slowed down 3rd member gasket leaks on bolts above the oil level in the past by simply clearing the housing vent. Works wonders! Remember we are talking about a pressurized oil mist here.
If you think about what the oil does in a rear end, the things you can and cannot do fits a bit better in place.
BTW- In cars such as a Cobra DO NOT run c-clip axles. Way too dangerous. And that's not a thing I will even debate about.
cobrashock

But Ron,,,,
the 8.8" Ford rear end DOES use C clips to retain the axles. So are you saying, in your opinion, you NOT recommend anyone run the 8.8" rear end?

I can understand your logic. IF the C clip comes out, breaks or what ever, you WILL loose your axle and wheel and quite possible WRECK the car. BUT, is the risk really "that" substantial?

Ernie

I think you should only worry about it if you have enough torque and friction on the tires to snap an axle. 8.8's are usually pretty stout, and if you have a 31 or higher spline, it makes it that much stouter. I've never really heard of anyone breaking an 8.8 on the street. Now launching at a drag strip with slicks would be a different story.

NEED CLARIFICATION
 

Uh...WOW...cobrashoch this is worthy of an emmy.....I think if grease is in the rear end other than gear oil there is a BIG problem. I would think that Grease has to get very hot to create an OIL mist...And by magic it lubricates all the parts except the ring and pinion.....
So the seals create gear oil.....but not all of it....
Some rear ends have the oil in the tubes and the axles pump it into the center? But others pump it out of the center down the axles? If you go in Reverse for a long time it will pump all the fluid, I mean grease the wrong way....Is this right?
Refer to my earlier post of comparing 8 inch, 9 inch, 8.8" and 7.5"...May be a little confused...blykins posted a picture of a 9 inch axle tube with seal inside, and if he showed the axle bearing it would be pressed on the axle, a sealed bearing, after the seal....Which every 9" Ford, drop out center section rear axle that I have ever worked on, read about...etc etc....has had.
....Uh....No comment.....
So, boiling hot temperatures in the rear is OK, the oil mist doens't go through the vent, only the water.....And with a vent the rear axle is not under pressure by oil or grease.."WHATEVER."
Not from old gear oil, no filter, clutch material, grease from checking tooth/wear pattern, but because it never got hot enough to boil the water.....
Especially if you run the wrong viscosity oil......engine yes, rear axle????
So if you put seals in, oil/grease will get to the bearing, but if you don't put them in oil/grease will get to the bearing....unless you don't go around corners...or will the axle pump keep it in the center....
So it will get into a sealed bearing....but I thought Or changing Axle seals!!!
So by clearing the vent, so that it relieves any backpressure that built up in a sealed housing, it stop leaks of too much pressure....
That never reaches the vent.....
Atleast we have oil now.....
If the rear end gets a pressurized oil mist, why would a 2000 Cobra R have a pump to cycle the gear oil through the rear diff cooler....And if the rear end needs to boil water, is the cooler to keep it at the boiling point???
8.8" is a strong axle, not as strong as a 9", but can be built very strong....It all depends on intentions/output of motor/tranny/gear ratio which will give you required strength needed of rear axle based on torque multiplication factors.....you can run C-Clip eliminators on an 8.8" to prevent this and is a NHRA requirement for Vehicles running I believe 10.99 and quicker you HAVE to run aftermarket axles and C-Clip eliminators....ANYTHING that is in NHRA Rule book is the way to fly as anything else you are just putting you/your car/ and others in danger of something that may fail.............Although if you are planning on going off roading, C-Clip eliminators don't hold up well to side loads..........
I am only writing a response to this so that people see that not all questions are stupid, and not all answers are correct... and vice versa.... everyone makes their own decision based on facts presented or known..... Hope this thread is an example of that...

I have a 9" in my 1967 Mustang Fastback (Eleanor Clone), an 8.8" in my 2001 Mustang GT, my center section is in my brother 1967 Mustang Convertible (He wanted 3.50 posi, instead of 3.00 open)....His car originally had an 8", but we picked up a 9" axle from a 69 Cougar....my father 1965 Mustang Fastback has a 8" 2.73 open (Oh yeah).....I have alot to compare too, this doesn't include the 2 (1989) 5.0's I've had, 1973 Bronco Sport, 1974 Bronco (Parts Truck), 1971 Mach I I pulled my Cleveland out of and 9 inch, 3 1967 (Coupes) (6 cyl's)....numerous friends cars that I work on... etc. etc....not to mention all the cars we build here or have worked on.....Food for thought......
After re-reading your first response I can't even comment anymore, other than call Moser and talk to them again.....
Brian

www.teamcracing.com