Sealing a tight fit 1

[Dave21426]

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.

 

[CoryPad]

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

 

[MiketheEngineer]

That is why they sell seals!!

 

[mfgenggear]

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.

 

[Dave21426]

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.

 

[kingnero]

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, ...)

 

[mfgenggear]

high temperature rtv

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

 

[Dave21426]

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?

 

[hydtools]

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

 

[CoryPad]

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-1554.htm?nodeid=8797928194049

 

[mfgenggear]

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.

 

[Dave21426]

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.

 

[Tmoose]

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.

 

[CoryPad]

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

 

[Dave21426]

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.

 

[Tmoose]

I was thinking the ends of the shafts are typically covered up by the tail shaft housing or the bell housing.

http://www.fordification.com/tech/images/3spd_T89C-F.jpg

 

[DesignerGuy16]

If it was working before, maybe you could use something like these:

http://vsm.skf.com/en-US/HeavyDuty/KitsAndTools/SpeediSleeve.aspx

James Spisich
Design Engineer, CSWP

 

[mfgenggear]

designerguy

very good

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

 

[hydtools]

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

 

[Oldhydroman]

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