915 Trans - paper gaskets

Shawzy · 08-04-2002, 07:13 AM

OK gents...

Almost ready to reassemble the 915 and I need advice on the gasket situation.

I have some adhesive paste designed to replace or help gaskets seal (not DOW CORNING 731 unfortunately). I have a new gasket set for the re-assembly of course but I am wondering if I should place some gasket sealer on the casing before torquing it up.

My parts guy said "fine, but make sure it is of the non-drying variety". Non-drying??? Is he talking a bit of swepco here? Or is he referring to not using an epoxy-like paste the dries rock hard?

Just wondering if you guys used any 'helper' with your gaskets or if you just put it together dry as a bone. I am thinking of using this same gasket helper on my new valve cover gaskets also. Can I do more harm than good with this idea?

ChrisBennet · ChrisBennet's Garage

The paper gaskets will weep/wick out tranny fluid if you put them in dry. I rub Loctite 518 (red stuff available at NAPA) into the paper gaskets before assembly. Some people use 274 (orange case sealer).

The following is probably "wrong" but it is what I personally do.
I know I'll be the next one disassembling the transmission so I try to save myself some work by making the gasket stick to the easy-to-scrape side of the joint (the one that doesn't have the studs sticking out of it) when I disassemble the tranmission. When am putting the joint together I wipe down both sides of the joint and check for burrs. On the side I want the gasket to stick to, I clean it with Brake Kleen so the gasket will adhere well. On the "studs side" of the joint I don't mind if there is a slight oily film.

-Chris

john walker's workshop · 08-04-2002, 07:57 AM

if you use a brush on, or paste type sealer on thin paper gaskets, the sealer will squish outwards as the parts are torqued together, taking the paper gasket with it.
spray K+W coppercoat is what i use. allow it to penetrate the paper and dry out somewhat before torquing.

Jim Sims · 08-04-2002, 08:02 AM

The tech rep associated with PCA told me to install them dry but to ensure that every bit of the old gasket must be removed and without marring the sealing surface. Hard to do especially with 30 year old gaskets cooked onto to magnesium alloy. However we did it by using wooden and plastic scapers and careful application of gasket removing compound. The PCA rep also said if the housing sealing surfaces have slight scratching to then apply a very thin film of silicone rubber sealant to the gasket. He repeated that it should be very thin; "essence" of silicone is the term he used. Our gasket sealing surfaces were in good shape so we installed our gaskets dry. We had one joint start to weep very slightly (about 1 drop of Swepco per month) after about a month. We retightened the screws and the weep went away. If I were to install the gaskets again I would probably use either the thin coating of silicone rubber or perhaps the non-hardening Curil-T compound. Jim

tbitz · 08-04-2002, 07:50 PM

When I did my rebuild, I ended up using Loctite 574. I cleaned both surfaces of the case using an x-acto with great care to not scratch the case. In hind sight I should have use something plastic like Jim recommends. I don't know if I would get the surface as clean as I did though.

I applied a very thin amount the 574 on both sufaces of the paper gasket. Then tightened her up.

Seems to have worked. I've been under the car a couple of times and haven't seen a leak, yet.

Cheers,

Shawzy · 08-05-2002, 09:13 AM

ok

i have a few options here that i will decide on, and give a report in due time.

thanks once again boys.....