glue or sealant???

[sirbean]

I have the hydraulic tank out of a 743. The fitting in the bottom of the plastic tank was leaking. The fitting is a SAE 12 oring fitting. My question is this. The threads had a type of sealant or glue on the threads on top of the oring. Any guess what that is? Any idea on how tight to make the fitting? Thanks

 

[melli]

As far as torque goes, a manual (SPEC pages) would tell you (depends on size). Excerpt from my manual: Flare Fitting/O-ring flare fitting Use the following procedure to tighten the flare fitting: Figure SPEC-40-3 Tighten the nut until it makes contact with the seat. Make a mark across the flats of both the male and female parts of the connection (Item 1) [Figure SPEC-40-3]. Use the chart below to find the correct tightness needed (Item 2) [Figure SPEC-40-3]. If the fitting leaks after tightening, disconnect it and inspect the seat area for damage. New o-ring, about 2 hex flats, and old o-ring, about 1 hex flats. Larger size, less flats. I suspect the 'sealant' was locktite. Was it blue/red?

 

[sirbean]

As far as torque goes, a manual (SPEC pages) would tell you (depends on size). Excerpt from my manual: Flare Fitting/O-ring flare fitting Use the following procedure to tighten the flare fitting: Figure SPEC-40-3 Tighten the nut until it makes contact with the seat. Make a mark across the flats of both the male and female parts of the connection (Item 1) [Figure SPEC-40-3]. Use the chart below to find the correct tightness needed (Item 2) [Figure SPEC-40-3]. If the fitting leaks after tightening, disconnect it and inspect the seat area for damage. New o-ring, about 2 hex flats, and old o-ring, about 1 hex flats. Larger size, less flats. I suspect the 'sealant' was locktite. Was it blue/red?

A clearish yellow..not as dark as dried wood glue. The fitting is screwing into the plastic threads of the tank so I like the idea of some kind of sealant and just seating o-ring. Thanks for any help. Anything stick to that tank plastic?

 

[melli]

A clearish yellow..not as dark as dried wood glue. The fitting is screwing into the plastic threads of the tank so I like the idea of some kind of sealant and just seating o-ring. Thanks for any help. Anything stick to that tank plastic?

I'd use locktite myself...coupled with o-ring, it shouldn't loosen nor leak. Loctite 5452 or 243 is made for your app (sealant/thread locker).

 

[SkidRoe]

A clearish yellow..not as dark as dried wood glue. The fitting is screwing into the plastic threads of the tank so I like the idea of some kind of sealant and just seating o-ring. Thanks for any help. Anything stick to that tank plastic?

Providing the threads are in decent shape, this sounds like an application that I would generally use a cream-style pipe sealant, like Loctite 592 or equivalent. This stuff never truly hardens, fills gaps, and resists vibration. It will also help the o-ring do its job. They also work well even if there is a bit of oil residue
Thread lockers like 242, 243, 262, 273, etc. are not the best in this situation. They will prevent the fitting from loosening, providing you can get rid of all of the oil residue, but you will be likely looking at another leak at some point.
My $0.02.

 

[Tazza]

Providing the threads are in decent shape, this sounds like an application that I would generally use a cream-style pipe sealant, like Loctite 592 or equivalent. This stuff never truly hardens, fills gaps, and resists vibration. It will also help the o-ring do its job. They also work well even if there is a bit of oil residue
Thread lockers like 242, 243, 262, 273, etc. are not the best in this situation. They will prevent the fitting from loosening, providing you can get rid of all of the oil residue, but you will be likely looking at another leak at some point.
My $0.02.

I can't remember the number my dad said, but they use it at work all the time to seal hydraulic fittings. At the base of the tank, there is no real pressure, just about any thread locker suitable for working in oil should do the job as long as all the threads are clean of any oil when you install them.