Making replacement hydrostatic transmission case gasket to stop oil leak (Cub Cadet 127).... I really don't want to screw this up.

[EVVFarms]

I am attempting to fix all the oil leaks on my Cub Cadet 127 tractor. I have most of them fixed with the exception of a leaking gasket on my hydrostatic transmission case. I thought I could order the part based on various web searches, however, after making several calls nobody seems to have it any more (Part# 394865-r1 or 3102875) so that means I have to make one. My first attempt success rate in fixing oil leaks hasn't been great so I thought I would post my plan and let members tell me if they think it will work or if they have a better idea.

The original gasket measures 0.0095 thick. Although I haven't scoured the earth looking, the thin gasket material isn't easy to find, however, I have heard of others using file folder material. It measures 0.010, which when compressed makes it perfect. So my plan is to use this file folder material with a very thin coat of permatex Aviation Form-A-Gasket No.3 on both sides of the paper gasket. I am not using the file folder material to be cheap, I just think it should work.....but again I don't have any real world experience in this and I would love to hear the opinion of others that have more experience than me. This is a huge PITA to take apart so I want to do it right the first time.

Also, I am not replacing the round output shaft seals. I hope I don't regret this. They aren't leaking, and I don't want to open up a can of worms by going deeper than necessary. Again, if this is a bad idea feel free to let me know.

Everyone's help is very much appreciated, thank you!

Best regards,
Ryan

 

[joecdeere]

found this just googling around, didn't know if you'd called them -

 

[EVVFarms]

Unfortunately most companies list it but don't actually have it. I will do another round of calling in the morning. I am curious if the group thinks my alternative plan with work. Thanks for doing the look up though.

 

[5030]

Any auto parts store, especially NAPA will have sheet gasket material (where I get mine actually) and I don't believe the gasket thickness (too thick or too thin) would adversely impact anything. However, instead of using Permatex, get yourself a tube of 3 Bond gasket maker and use that. I make a lot of gaskets, it's really pretty easy. 3 Bond is all I use now.

 

[MTGreen]

I would be very cautious using RTV (Permatex type stuff) in a hydrostat. Suggest using an absolute minimum amount as any blobs that break off internally can cause flow restrictions or other problems.

Also I would hesitate to use cardstock/file folder material as it will likely disintegrate with oil exposure over time. Rather I would find thin gasket material that's designed for oil exposure even if it's a little thicker. It's unlikely that the thickness is critical here

 

[oldnslo]

Like MT states be very cautious on the application and use of RTV On those case halves. There should be minimal pressure in that case so a good paper gasket or careful application of form-a-gasket should work. Surfaces must be completely oil free for form-a-gasket to work and follow assembly and cure time instructions.

 

[EVVFarms]

Like MT states be very cautious on the application and use of RTV On those case halves. There should be minimal pressure in that case so a good paper gasket or careful application of form-a-gasket should work. Surfaces must be completely oil free for form-a-gasket to work and follow assembly and cure time instructions.

I am sure it would be fine, but I have also heard horror stories about RTV on pumps / motors / hydrostats which is why I thought I would focus on using the Aviation form-a-gasket No.3. When you said stick with form-a-gasket, I assume you meant the Aviation form-a-gasket No.3 like I mentioned in my original post.

In my search for the part, I did come across a guy that focuses just on the the older cubs and he said that thickness does matter. I also suspect the group is right about finding the appropriate material that is made to handle the oil so I will go on a search tomorrow for the correct gasket material and thickness. Better safe than sorry, sometimes I just need somone to keep me on the right path.

Thanks everyone, feel free to keep adding comments. My mind is like a sponge, I am happy to keep absorbing whatever wisdom you want to bestow on me.

 

[oldnslo]

Yes the #3 product would be fine. Without physically looking at that unit I suspect changing thickness a couple thousands of an inch would not matter a 0.03 thick gasket would affect the pre-load on the rotating group(s) and may cause excessive leakage.

 

[EVVFarms]

Yes the #3 product would be fine. Without physically looking at that unit I suspect changing thickness a couple thousands of an inch would not matter a 0.03 thick gasket would affect the pre-load on the rotating group(s) and may cause excessive leakage.

Sounds like I have my marching orders for tomorrow. Thanks for the help!

 

[seville009]

Just a thought, but if you have any club cadet dealers/repair shops around, physically go there with your old gasket or the specs to see if they have it, as they probably have to deal with this too on occasion. It wouldn’t show up on an internet search, because they probably don’t generally sell them. They might not have that specific gasket, but might have material, or could give you a supplier to contact.

If there are no club cadet dealers around you, then any tractor/equipment repair shop may be worth checking.