Rear Axle questions

[Keyspider]

I have a 74 spider, it has an oil leak from the diff. I cant see exactly where... I posted this question on another section but little response.
Someone suggested that it was the pinion seal... How difficult is it to remove the flange... does it upset any diff torque settings?
I see there is a bolted casting on the bottom, does it use gaskets or sealant?
Also the car lifts a wheel and spins easy, so I am unsure if it has a LSD or if it has how can I test it? I think the axle was swapped at some time.
How can I tell if it has one, cos it picks up its inside tire and spins it good!

Anyone?

[grizzly]

I've read you can do this on the car. Do a google search for "the art of tool making" Someone in AROC Australia wrote this and its good. I just replaced my pinion seal by dropping the rear end; I also wanted to replace all the suppension bushings. You will a special tool to remove the pinion nut, from there you can remove and replace the seal. Additionally I removed the bottom pan and clean it up a little. I used gasket sealer with the old gasket when I put it back together (blue). You could probably use one or the other or even both like I did. Hope this helps.

Read the aussie article

[Andrew]

If you're talking about the center of the diff, there are a couple places to leak. Outer oil seals at the wheel end can leak too.
The most common is the pinion seal. To replace, remove rear of driveshaft, get the special castellated socket and lock tool to undo the pinion flange nut, remove the pinion flange, carefully pry out and replace the seal, put everything back. Mark each piece before removal for identical reassembly.
There is a sump, the rectangular base to the diff, that has a gasket, and can leak. There is also the sump drain, and the filler plug. They don't use gasket sealer. They should have a copper or aluminum sealing washer under the head of the plug.
In theory the diff could leak through the side seam where the axle tube assembly bolts to the diff housing, especially on the large side. It doesn't have a gasket, but uses sealer. You have to take the whole thing apart to address that.
I'd clean it all really well, maybe steam clean (but close off the vent tube first) and then watch closely where the leak reappears from.
Andrew Watry

[Paradiso]

I need to replace the pinion seal on my 92. Besides the socket are there any other specialised tools required? Once the flange for the driveshaft is removed, can the seal just be pried free and the new seal just pushed into place?

[Andrew]

You've got to have the castellated socket unless you want to drive the thing off and on with a punch and a big hammer, not recommended. It's torqued to 80+ ft lbs. I think Eriminas has reproductions, and Jon Norman used to have new ones. Don't know if that's still true. They come up on ebay periodically.

It's best to also have the big L-shaped factory tool to lock the pinion flange in place while you loosen and tighten the nut, but you can make do with some kind of angle iron or something, or if you're using an air wrench you probably don't need it at all.

The seal is a standard type, and a normal seal-pulling tool (a doubled-sided hook thingy) ought to do the job fine. Be careful not to let the hook score the face the seal is pressed in against. When installing the seal, use a large socket or similar round heavy thing that will press right against the vertical edge, and not deform the flat face. Make sure it's square, and work slowly and carefully to drive it in all the way. Notice before removal how far in it sits. They also make seal-driving tool kits, and there's a factory seal driver, but they're not commonly found.

Andrew

[Paradiso]

Thanks Andrew!

[papajam]

Also lubricate the lip of the new seal.

[Keyspider]

Thats great info!
Thankyou all!
I found the link about making the tool... here it is.

http://www.geocities.com/MotorCity/D.../ringtool.html

Any ideas on the LSD issue?
I saw that you can get a replacement clutch pack... what is that?

[VeloceOne]

Greetings,
When using the socket do NOT use an impact on it, you will tear the teeth off if you do.
Regards, Ian.

[adam1750]

I made the tool from that article-came out really ugly from my ineptitude but worked fine; use an air wrench to simplify things

Adam

[Roadtrip]

Check out this thread.

Pinion seal change problems

I've already been thorough what you're about to do. Chances are your axle pinion bearings are as worn as mine, so don't expect to torque the pinon to the 60 ft/lb spec.

Here's a picture of the limited slip differential casting.

[Keyspider]

So, John... The LSD equiped axles are different casting to the normal!
Wow, thats a good one!
I will look and see this weekend...
Thanks

[Andrew]

Regardless of the condition of your pinion, you do need to torque the nut up to spec. They back off pretty readily if not torqued. If your pinion is that loose it's probably time to be looking for another good axle, or rebuild it.

It's recommended to loctite the nut; I'd use removable med. strength.

Note that the castellated nut, and matching socket, are one size for 1300-1750, and a larger size for 2000. 2000 is the same, whether LSD or not.

Andrew

[Keyspider]

Thanks guys...
Well Roadtrip... I guess I know why I get lotsa wheelspin now...
here is my rear axle case....

Good news is that my other one has the LSD!
Thanks

[Roadtrip]

I believe that the 74s were supposed to be fitted with LSD axles, however, knowing Alfa, they used what parts they had on hand at the time.

As far as torque on the pinion nut, I'd be very surprised if you could torque the pinion nut to 60 ft/lbs and not lockup the bearings. At least that's what happened to mine. The bearings in my axle are worn, no doubt, but no filings in the oil and no noise. I could only get about 15 ft/lbs of torque after replacing my pinion seal and still have acceptable preload.