Re: [T3] A couple of AT questions

[Jim Adney <jadney@vwtype3.org>]

On 8 Aug 2005 at 16:31, Daniel Baum wrote:

> Jim Adney wrote:

> > Leakage from the output shaft seals on both sides would be gear oil, so 
> > they
> > are not a suspect here. There is a joint between the actual AT housing and 
> > the
> > final drive housing, however, which is secured by 4 long studs. Check the
> > torque on those nuts to make sure that they are tight to spec. A couple of
> > people here have reported those coming loose (or having never been 
> > tightened properly.)
> 
> There's no way I can get a torque wrench on those nuts, except maybe with a 
> wobbly extension, which I don't have. I think they're OK - they don't feel 
> loose and I couldn't see any sign of leakage.

 Leakage would come from the seam between the final drive housing and the AT 
housing, not from under the nuts. I would just put a wrench on each nut and 
give it a little tug. If they don't move you're probably fine.

> Meanwhile, I had a closer look at the driveplate today, and cleaned it up.
> 
> Here it is, after I cleaned up the central hub:
> 
> http://www.type34.info/temp/Drive%20plate.jpg
>
> The bolt in the hole is for orientation when I put it back.

The easy way to mark orientation is to use a crayon to mark the bore of the 
hole where the gland "nut" came out. You can mark both parts in a single swipe 
and still move everything around and put it back together. This really isn't 
important unless you're pretty sure the original factory orientation hasn't 
been lost already, which is not at all clear in your case.

When I take a virgin engine apart, I stamp a mark on the face of the flywheel, 
under where the gland "nut" washer would go, and a matching mark at the bottom 
of the gland "nut" hole. Berg uses a letter V as a kind of arrow. That seems 
pretty reasonable so that's what I do, too.

> The hub itself has a groove in it. Is it supposed to be there, or has it 
> been worn into it over the years by the oil seal?
> 
> http://www.type34.info/temp/Groove.jpg

No, that's a bad thing; that surface should be smooth. The best repair would be 
a good replacement drive plate, but those are hard to find, even here. I 
suspect that a good machinist could clean up that surface and keep it round and 
centered, but it would have to be very carefully done. It looks (I'm guessing) 
like they would have to remove about 1mm from the diameter of that hub, but the 
standard oil seal should be able to fit down to there and still have SOME room 
to wear. This might cost a lot to have done, and might not be successful.

Another possibility is a kind of repair sleeve which you would press over the 
old damaged surface. They are a stainless steel sleeve, about 1/4mm thick, with 
a beautiful outside surface finish. In the US, we can buy these as "Speedi 
Sleeves" made by Chicago Rawhide. They install right over the old surface and 
are so thin that the extra diameter is no problem. Because they do not require 
machining, you are assured that the new surface will be as well centered as the 
original. Before you install the sleeve, you would want to file down any 
material on your old surface that was standing above the original diameter. 

You can check out the "Speedi Sleeve" concept at:

http://www.chicago-rawhide.com.au/Products/speedi.htm

Your local machine shop should know about these and be able to find you one in 
the right size.

Note that if you google on "speedi sleeve" you'll also get hits from SKF, who 
also seem to sell these, which makes it more likely that they will be available 
world wide. Oddly enough, when I go to the SKF link, I get a Chicago Rawhide 
URL which seems to have been written specially for SKF. Unfortunately, I don't 
seem to be able to find a list of available sizes online.

Looking a bir farther, I find that other seal companies make similar products. 
Federal Mogul (National) makes Redi-Sleeves.

http://www.federal-mogul.com/cda/content/front/0,2194,2442_7705_7689,00.html

I have no experience with either of these, but one of our machinists here 
recommended them. I believe he's used them a lot. I found one link on the web 
that mentioned that they were expensive. I don't know how expensive that might 
be, but one would have to compare that to the cost of remachining or 
replacement.

Okay, I finally found an online size listing. This doesn't look like much of a 
URL, but it seems to work to bring you a pdf of the Speedi Sleeve catalog.

skf.hu/images/5149_E.pdf

ISTR that the seal ID is 70mm so if that's the hub diameter, then you have a 
couple of choices available to you. The CR in the part # stands for Chicago 
Rawhide, but I gather that the other maker uses the same numbers. You'll have 
to make a careful measurement of the actual hub diameter (three measurements at 
different places and take the average) to determine the correct sleeve to buy.

It looks like these sleeves can be bought at any standard bearing supply house 
and that you could just install it yourself. Instructions and an installation 
tool come with each sleeve.

Remember to lube the drive plate and new seal before you install the drive 
plate on the engine.

-- 
Jim Adney
jadney@vwtype3.org
Madison, WI 53711-3054
USA

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