Resealing early diff side covers

[ninfelise]

It was recommended that I post this here instead of the Beetle 1958-1967 section, my apologies if this has been covered.

I'm in the process of doing a "reseal" on my 61 transaxle and am questioning if the gaskets I used on the diff side covers were the proper thickness or how much they have effected the bearing preload, if any. The old gaskets were so deteriorated that I couldn't get a good thickness measurement upon disassembling. I questioned if they were even gaskets or if it was just a coat of sealer.

Also when I removed the diff side cover on the drivers side (clutch cable bracket) the carrier bearing came off with the side cover and the shims under the bearing remained on the diff carrier. The passenger side cover came off and the bearing remained on the diff carrier. I did each side by itself and didn't actually have the diff assembly completely out of the transaxle. I assembled the covers in reverse order using a single paper gasket per cover with a thin coat of high tack aviation sealant. Torqued them to 22 ft/lbs.

Some questions I have are: Should I be concerned with the diff side cover gasket thickness? Should I ditch the gaskets and just use some aviation sealant?

I have the light blue and orange Bentleys and really need the early dark blue one! This is the earliest car I've owned.

[Casting Timmy]

Tough to say, not knowing what you still have on hand or have available at your disposal.

Today I think there are only two side cover gaskets you can get, the kits actaully cost the same, but the quality difference is not even comparable. The cheap kit you have to clean up the gaskets (light brown color) and those are very thin. The good kit is a red color and are thicker and cut correctly and require no clean up.

I'd be tempted to put it back together just with sealant, I don't think giving those old bearings a little preload back would be a bad thing at all.
_________________
T1 IRS Rebuild Book on Lulu.com
http://www.lulu.com/shop/tim-marshall/t1-irs-transaxle-book/paperback/product-24055997.html
As seen in Volks America Issue 14 Page 11 (Full page review)

[andk5591]

Can't help on the shimming. I just use enough gaskets to do the job. as far as an actual sealer, most of the trannys I work with have some deterioration. I ALWAYS use Permatex Right Stuff (coat all the gaskets) and never leak a drop.
_________________
D-Dubya Manx clone - 63 Short pan,1914.
Rosie 65 bug - My mostly stock daily driver.
Woodie 69 VW woodie (Hot VWs 7/12).
"John's car" 64 VW woodie - The first ever
Maxine 61 Cal-look bug - Cindy's daily driver.
Max - 73 standard Beetle hearse project - For sale
66 bug project - Real patina & Suby conversion
There's more, but not keeping them...

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The paper gaskets on an early swing axle side cover are not shims, they are simply sealing gaskets that are used one per side. The metal shims under the carrier bearings are what sets the preload/backlash. The thickness of the gaskets have to be taken into the measurement though. Ideally you would want .005-.010 worth of side cover lift/preload. If you have a used trans in a stock application, you could get away with less. I would clean all gasket material from both covers, and assemble them dry. Then loosen the nuts on one side to see how much, if any the side cover raises off the main case. If it doesn’t raise at all, then like Tim mentioned, you could most likely get away with simply applying some sealer without any gaskets. If the cover raises, do the math. It’s been a long time since I messed with an early sidecover gasket, but it sticks in my mind they are about .005 thick. If you have .015 worth of side cover lift, two .005 gaskets (one on each side cover) will give you .005 bearing preload. Anything deeper involved is going to require some way of measuring the backlash, and/or replacing the carrier bearings.

[ninfelise]

Thanks for the replies! I ended up pulling both side covers back off and cleaned everything up. I'm going to do some measurements dry fitting the side covers. I pulled the diff, both bearings stayed with it so the shims haven't been disturbed. I'm leaning towards a light coat of "the right stuff" over the 25 years of wrenching that stuff has never failed me and has amazed me several times! I like the aviation sealer but it has failed me on occasion. Part of me feels like I'm overthinking this and part of me feels if I don't do this its gonna bite me in the ass.

[ninfelise]

Alright, I just got done dry fitting the covers with no gaskets. I installed the passenger side cover first, installed the diff and then the drivers side cover. torqued both covers to 22ft/lbs. I then loosened the drivers side cover and it created a gap of .010" between the cover and the case. I torqued it back down and flipped the trans over and loosened the passenger side cover and found the gap to be .005". The gaskets I have are tan and measure .010" thick. I'm thinking I should use 1 gasket with the right stuff on the ring gear side cover (drivers side) and just use the right stuff on the passenger side cover with no gasket. I appreciate any opinions and or advice..again, I feel I might be overthinking this one!

[Casting Timmy]

Personally I would bolt it together dry with some gear marking grease on a few teeth of the ring gear. Put a 2x4 over the end of the side cover and give it a few love taps to make sure the bearings are seated in teh cover.

I'd really think your preload was probably more the old mag covers bending and flexing and popping as the bearings weren't fully seated than that's how much preload your trans has to it. The preload you give the bearings will go away with mileage, so unless it's a really fresh rebuild I'd kind of question what's really happening to get the side covers popping off.

You'll want to turn the diff over a few times in each direction and then take it apart to see if the grease pattern is matching up with the wear pattern on the teeth. If it matches the wear pattern, putting the same shim or gasket on both sides will keep the pattern, but change bearing preload. (Your gaskets on each side would give side to side movement of the diff.)

I'd just use your sealant of choice and know the bearing preload is a little higher than it was, but my guess is that you really have little to no preload in those old bearings. It's a very common thing to have little to no preload left in the swing bearings, so doing no gaskets will add it back and you'll know the pattern is correct from the dry run.
_________________
T1 IRS Rebuild Book on Lulu.com
http://www.lulu.com/shop/tim-marshall/t1-irs-transaxle-book/paperback/product-24055997.html
As seen in Volks America Issue 14 Page 11 (Full page review)

[andk5591]

My understanding has always been that the gaskets are acting as shims. You add or subtract gaskets based on what you have. Not a tranny guy, but that is what I have done when installing axles....
_________________
D-Dubya Manx clone - 63 Short pan,1914.
Rosie 65 bug - My mostly stock daily driver.
Woodie 69 VW woodie (Hot VWs 7/12).
"John's car" 64 VW woodie - The first ever
Maxine 61 Cal-look bug - Cindy's daily driver.
Max - 73 standard Beetle hearse project - For sale
66 bug project - Real patina & Suby conversion
There's more, but not keeping them...

[[email protected]]

[ninfelise]

Finally got a hold of some gear marking compound and did a few dry runs this morning. First 2 are with no gaskets the last 4 are with both cover gaskets installed. I haven't had to look at gear patterns for 20 years but I'd say both look decent, especially for a 59 year old set of gears. I'm leaning towards going with no gaskets with a thin coat of sealant and call it done..unless someone can point out any problems they see.

[Casting Timmy]

The first two photos almost look like it was before the diff was turned with the pinion gear.

The last 4 photos I like to look at the grease put on the teeth that didn't have brushed on grease. I like to put it heavy on a few teeth as well, and think it looks good.

I'd really go for no gaskets and call it a day. That way you know it's not a lose diff going side to side and they'll go the preload they want in a few miles anyways.
_________________
T1 IRS Rebuild Book on Lulu.com
http://www.lulu.com/shop/tim-marshall/t1-irs-transaxle-book/paperback/product-24055997.html
As seen in Volks America Issue 14 Page 11 (Full page review)

[Casting Timmy]

I would also say kudos to you for sticking with it and taking the time to learn and run the pattern.
_________________
T1 IRS Rebuild Book on Lulu.com
http://www.lulu.com/shop/tim-marshall/t1-irs-transaxle-book/paperback/product-24055997.html
As seen in Volks America Issue 14 Page 11 (Full page review)