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Sealing a tight fit

Sealing a tight fit

Sealing a tight fit

(OP)
I have an intermediate shaft in a transmission unit that goes thru a cast iron hole in the case. .0005 max gap and even with thick gear oil it leaks. I need something very thin that can get into that gap and seal it.

RE: Sealing a tight fit

If the shaft rotates, you need a proper part to do the sealing. Check FNOK, SKF, Parker, etc.

RE: Sealing a tight fit

That is why they sell seals!!

RE: Sealing a tight fit

I agree with all of the above. cory & mike
port the hole to accept the seal OD. see mfg web site.
in addition the shaft must be properly machined
to prevent the seal from failing & to seal properly.

HTH

Mfgenggear
if it can be built it can be calculated.
if it can be calculated it can be built.

RE: Sealing a tight fit

(OP)
Its not a rotating shaft, transmission usually dont work that way. This is for existing units in the field. Over time the shafts being taken in and out have created a looser tollerence. I was thinking of a loctite product.

RE: Sealing a tight fit

if your transmission unit shaft doesn't transmit rotation nor linear motion, then what does it transmit?

Any LocTite salesman will be able to guide you through the hundreds of LocTite products, depending on your specific application parameters (heat, gap, size, ...)

RE: Sealing a tight fit

high temperature rtv

Mfgenggear
if it can be built it can be calculated.
if it can be calculated it can be built.

RE: Sealing a tight fit

(OP)
I tried RTV, too thick. The intermediate shafts are stationary, gears have needle bearings and the gears rotate and slide back and forth on the shaft via the shift forks. Ever have an old erector set?

RE: Sealing a tight fit

If you have the space, put a Forsheda v-ring on the shaft and inside the case. It fits tight to the shaft and makes a face seal against the case.

Ted

RE: Sealing a tight fit

In automotive transmissions, it is commonplace for intermediate shafts to rotate and transmit torque.

For your application, you want to look at retaining compounds, for example Loctite 609 or 620 or 680.

http://www.henkelna.com/adhesives/product-search-1...

RE: Sealing a tight fit

maybe resurface the holes with brush on chrome, or nickel?

Mfgenggear
if it can be built it can be calculated.
if it can be calculated it can be built.

RE: Sealing a tight fit

(OP)
Of those 3 loctite which would be best for this application. They look similar in nature. mfgenggear, I had the same idea but dont want to take it apart.

RE: Sealing a tight fit

I'd check with Loctite, but if the oil wasn't there, I'd expect the amazing "wicking" green 290 would sneak right in.
If that bracket weren;t there, using up valuable space, I think gluing an external cap would work slick. Actually, I think with thorough de-greasing applying a fillet of RTV would work.

I'd be checking to be sure the breather isn't plugged.

There's always the "rub it with a bar of soap" trick.

RE: Sealing a tight fit

With the complete absence of operating environment details, it is impossible to say which product is most suited.

RE: Sealing a tight fit

(OP)
Well 609 has a low viscosity, that would be a good thing. Corypad, yes the intermediate gears turn but in this case the intermediate gears have needle bearings that ride on the shaft. The shaft just supports the stuff. Common place for non syncro transmissions pre-60's.

RE: Sealing a tight fit

designerguy

very good

Mfgenggear
if it can be built it can be calculated.
if it can be calculated it can be built.

RE: Sealing a tight fit

If the assembly is new and never been lubricated, the Loctite 609 will work. If the assembly has been in service and the joint is greasy, the Loctite will not work without degreasing the joint.

Ted

RE: Sealing a tight fit

Try Loctite 603 (or 243 or 263). These are oil tolerant products that will still work even if you can't do a thorough degreasing.

DOL

RE: Sealing a tight fit

(OP)
A sleeve with .00025 wall, good luck with that. Loctite 200 series is the only stuff like wicks so I may try that. Back in the day, 1940's, they used 600w oil but I am not sure where to buy a small amount of it.

RE: Sealing a tight fit

the only correct solution is to take it apart & repair it properly.
any time there is jerry rigging it will never work correctly.

loctite is a temporary fix, I have encounter this type issue before.
& it just leaks again. so then you have either fix it right or live with it.
loctite will be temporary fix.

Mfgenggear
if it can be built it can be calculated.
if it can be calculated it can be built.

RE: Sealing a tight fit

Put some saw dust & banana peels in there and sell it quick.

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The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.

RE: Sealing a tight fit

Seal weld the shaft on the outside then it can be ground if the shaft has to be removed.

RE: Sealing a tight fit

Spray it real good with brake cleaner, then see if a torch and plumbing solder would wick in? Not exactly an engineering opinion but that's what I would try in my garage.

RE: Sealing a tight fit

i like that Idea, if the solder will stick.
sometime it will just peel if isn't cleaned properly.
or leak but the leak would be small.

Mfgenggear
if it can be built it can be calculated.
if it can be calculated it can be built.

RE: Sealing a tight fit

also that it may not wick if there too much contaminate in between the surfaces.

Mfgenggear
if it can be built it can be calculated.
if it can be calculated it can be built.

RE: Sealing a tight fit

JB Weld

RE: Sealing a tight fit

Wrap some SS shim stock around the shaft and pound it in the gap?

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