Type of thread seal?

[wdchyd]

That’s the same thing my neighbor - who is a retired heavy equipment mechanic - told me ...

My moto:

Work on something like you’ll be the next guy to fix it.

 

[BWSwede]

#2 grease on the O-Rings and never-seize on the threads sounds good to me. I think I'll go that route.

Thank you all for your input.


Blane

 

[5030]

Lets throw this wrench into the fray... NPT Dryseal fittings need nothing alpplied to the threads.

 

[LouNY]

#2 grease on the O-Rings and never-seize on the threads sounds good to me. I think I'll go that route.

Thank you all for your input.


Blane

The best way in MHO also.

 

[rScotty]

Hello hydraulic gurus,

I will be rebuilding the hydraulic cylinders on my tractor. They all have end caps with internal threads and tubes with external threads. I assume there is a thread seal in there now and I am wanting to use a thread seal as part of the rebuild.

Does anyone have a recommendation for a Locktite (or other) product that is appropriate for the application. I contacted Locktite but they never responded.

(The tubes are about 3.25" diameter if that makes a difference.)

TIA,
Blane

I don't use any thread sealant on hydraulic fittings. Just a very little clean grease on the mating surface or O-rings..... and maybe a little bit more grease on the threads. I've never had a problem that I couldn't get to stop leaking - although sometimes it requires replacing the fitting. But I probably will run into a problem like that someday. So I'll be curious to see what others use.

I guess what I am saying is that I wouldn't start out by using a sealant of any kind. Assemble it as if no sealer is required. Most of your connections are going to be good, and if one isn't then I'd look it over carefully before adding anything.

If the connections are good it shouldn't need anything.

 

[RickB]

FWIW
Many (if not all) of the end caps I have removed have o-rings so no thread sealant should be required...

Agreed. And the only reason to use a qualifier is there is probably one out there somewhere that does. But I have not seen it yet. If the threads are on the dry side of the seal, use never seize on the threads to facilitate removal next time.

 

[wdchyd]

I don't use any thread sealant on hydraulic fittings. Just a very little clean grease on the mating surface or O-rings..... and maybe a little bit more grease on the threads. I've never had a problem that I couldn't get to stop leaking - although sometimes it requires replacing the fitting. But I probably will run into a problem like that someday. So I'll be curious to see what others use.

I guess what I am saying is that I wouldn't start out by using a sealant of any kind. Assemble it as if no sealer is required. Most of your connections are going to be good, and if one isn't then I'd look it over carefully before adding anything.

If the connections are good it shouldn't need anything.

Correct me if I’m wrong Scotty (and others), but my take is the OP is talking about threads on the cyl barrels, not a fitting.

Here’s what can happen if no one put neversieze or grease on the threads on an old repair. One cap came off hard, the other had to be cut off.

 

[wdchyd]

(Sorry for the upside down pic)

 

[rScotty]

Correct me if I’m wrong Scotty (and others), but my take is the OP is talking about threads on the cyl barrels, not a fitting.
Here’s what can happen if no one put neversieze or grease on the threads on an old repair. One cap came off hard, the other had to be cut off.

Yes. On re-reading I think you are right about his question being specific to the cylinder cap ends. My reply - and others - was more general for hydraulics & hydraulic fittings.

So on more thinking about it, I do agree that the cylinder caps are one of the few places around the hydraulic system where one could use a sealer. The threads are parallel so there is a potential leakage path to deal with. It's a path that lets water cree in as well as hydraulic fluid out. Since I now agree that we are dealing with external threads on the cylinder, there is no easy way for a cap sealer used there to get into the hydraulic system - which was my main concern.

I'd want to use something that doesn't harden so that it can creep under pressure - but very slowly - and that has the quality of being slightly gap filling. Some fairly thick never-sieze compounds seems to have those characteristics. So it would be a reasonable product to try in that location.

I've wondered why cylinder end caps tend to be hard to remove. It must have something to do with the repeated cylinder pressure. Other similar threaded connections don't set up so darn tight. The never-seize might help with that, too.....I doubt it would hurt.
rScotty