Pipe Threads #$%^&

[3Ts]

I've added some hydraulic lines to my tractor and had to use pipe threads in a few places. I used thread sealant on all pipe threads, but have a single fitting that leaks. I've gotten all but one tight enough to not leak, but the one is driving me up a wall. It is a 1/2" pipe thread quick disconnect at the end of a 6' hydraulic hose and it's leaking around the threads. It is possible to remove the hose but would be a lot of work to do so. I have crescent wrenches up to 2' (in length) for leverage but trying to tighten it further has been unsuccessful. My next step is to see if I can get a deep impact socket to fit over the QD but that will be several weeks before I can get into a town that has one. Any suggestions?

 

[Granthol]

If it’s a drip and you don’t ever need to get it off, jbweld?

 

[chim]

I've done just a little work on hydraulics. I used pipe dope that listed on the can it is suitable for hydraulic lines. No leaks.

 

[TractorGuy]

Aviation Permatex.

 

[fruitcakesa]

Pipe dope and teflon tape has worked for me on NPT stuff

 

[Oaktree]

I have crescent wrenches up to 2' (in length) for leverage but trying to tighten it further has been unsuccessful. My next step is to see if I can get a deep impact socket to fit over the QD but that will be several weeks before I can get into a town that has one. Any suggestions?

+1 on the teflon tape/thread dope. Could it be that the male fitting is bottomed in the female? Trying to tighten further would just strip threads and make things worse.

 

[the old grind]

Permatex No 2, thicker than No 3.

LocTite 567 is a 'high-temp' alternate to 565. These two aren't like the 'green stuff' and most other teflon-based brush-on dopes. They have a working time (~5 min) and a curing time (20-30 min) like many of the company's products. This gives them an edge over more basic plumbing dopes.

IMO, Parker fittings are worth the $$ for better fits, fewer rounded hexes when tightening to stop leaks, and fewer 'do-overs'.

TSC stuff (hoses w/NPT male ends) is among the worst we can easily find. I suggest 'chasing' the lumpy plating off their male NPT threads with a regular die set. :2cents:

 

[LouNY]

Over tightening sae pipe threads causes more problems then it solves.
A small amount of a teflon pipe dope or 3 wraps of teflon tape should be sufficent to seal a npt fitting.
If it needs more the fitting is low quality, teflon tape is not a sealant anyways it is a thread lubricant allowing the thread distortion to occur which is what seals npt threads.

 

[the old grind]

.. A small amount of a teflon pipe dope or 3 wraps of teflon tape should be sufficient to seal a NPT fitting.
If it needs more the fitting is low quality, teflon tape is not a sealant anyways it is a thread lubricant allowing the thread distortion to occur which is what seals NPT threads.

This! ^^^ :thumbsup:

 

[hawkeye08]

Had a sae NPT fitting leak on loader last year, no amount of thread dope/tape would seal it, had to replace fitting.

 

[jaxs]

Same as any mfgred product, threaded parts/fittings can be defective. Replacement is preferred but thread repair is possible. I clean male threads,melt thin layer of solder into threads then dope and assemble. If solder prevent's assembly,I chase a few threads with pipe die.

 

[WranglerX]

Hate PTFE tape, it commonly referred to as a sealant but its actually a thread lubricant designed to allow you to put more turns on fitting to tighten it to cause better thread interference (seal)...

Have better luck with most every type of threaded connection using product below be it plastic, brass or steel...



D.

 

[ericm979]

I hate NPT for hydraulics too but it's on a lot of fittings. Loctite 545 is made for sealing threads on hydraulic connections. It works much better for me than the Permatex goop for hydraulic threads. It's an actual sealant not just thread lubrication. With it I don't have to torque the fittings down quite as hard.

 

[/pine]

NPT fittings are not made to be reused...after they have been tightened once...

 

[kennyd]

NPT fittings are not made to be reused...after they have been tightened once...

ESPECIALLY after they have been over-tightened.

 

[3Ts]

NPT fittings are not made to be reused

I was aware of this and was hoping I just didn't have it tight enough. But, it looks like I'll be replacing the fittings and I'll try that Loctite 545.

Thanks to all.

 

[mjw357]

The loader on my B3200 has leaked almost from the time I bought it new. I tore into it this week to find the dealer had used sone sort of tape on the quick connect fittings, the material had the consistency of chewed bubble gum. Cleaned it all up and used Teflon pipe dope. Several hours of shoveling and leveling crushed limestone, no more leak.

 

[jaxs]

The loader on my B3200 has leaked almost from the time I bought it new. I tore into it this week to find the dealer had used sone sort of tape on the quick connect fittings, the material had the consistency of chewed bubble gum. Cleaned it all up and used Teflon pipe dope. Several hours of shoveling and leveling crushed limestone, no more leak.

Never leave home without it.:thumbsup:

 

[3Ts]

I've got some of that 545 on order from Amazon, no one in town had any. I'll let you know how it turns out once it arrives.

 

[keljan11]

So many on here have said npt fittings aren稚 designed to be reused. New is always best, but being a pipefitter for over 40 years, I have reused a 吐ew threaded fittings, and rarely had an issue. Just check the threads for damage. Thread tape should be for designed purpose (oil, gas, water, etc), and there is a correct way to put it on. Wrap it on going with the threads. Also, never bury the threads into the other fitting. I致e used threaded pipe with Teflon tape on 2-3000 psi systems doing hydro tests using old reused fittings without issues. It can be done.