Hydraulic hose problem

[J_J]

http://www.henkelna.com/us/content_data/141299_LT5557_5452SSF448695.pdf

 

[tcreeley]

http://www.henkelna.com/us/content_data/316041_FINAL_LT4680_AAM_Do_It_Guide_v7.pdf

 

[tcreeley]

Of course the slow drip was there this morning, after using thread sealer paste. I went to my backup hose and fittings I bought (for when the next hose blows!) and this time I used plain old PTFE teflon tape. I used 21/2 wraps and kept it back up from the first two threads on the male end of the hose, and I screwed on the adapter. Finger tight, grip tight (wrench), and then a little extra. I pulled the new leaky hose off and put this one on - no leaks. I can live with that! Pics are taken after I ran the tractor.
View attachment 385763View attachment 385764 - my 22mm, 3/4, 7/8 wrenches! View attachment 385765
Re specs on wrenches and fittings, I found that of the two same Chinese made adapters, one worked with the 22mm, the other worked with the 7/8. We are back to the good old days when we used to joke about it being made in Hong Kong. Hard to know what to expect. As long as it works, that's what we can hope for.

 

[Discount Hydraulic Hose]

You need some kind of thread sealer on NPT fittings.

http://www.henkelna.com/us/content_data/141299_LT5557_5452SSF448695.pdf

If he's buying hydraulic fittings, they are most likely NPTF, and not NPT

I'm starting my own online campaign to get more people to use the correct term. NPTF (National Pipe Taper Fuel) is a tighter fitting, dryseal version of NPT. The general thread dimension are the same, but the threads are designed to fit more tightly together. Technically, this connection doesn't need sealant (the first time), but one you have tightened the fittings the threads become deformed, so anytime you disassemble a connection and reassemble it again, sealant will be needed.

Almost everyone I know uses sealant the first time and every time, just to be sure.

 

[J_J]

NPT verses NTPF

NPT Vs. NPTF Taper Pipe Threads

 

[CJONE]

Almost everyone I know uses sealant the first time and every time, just to be sure.[/QUOTE]



And a lot of times with just sealant they will still leak. That's why I use both dope then tape. CJ

 

[Threepoint]

If he's buying hydraulic fittings, they are most likely NPTF, and not NPT

I'm starting my own online campaign to get more people to use the correct term. NPTF (National Pipe Taper Fuel) is a tighter fitting, dryseal version of NPT. The general thread dimension are the same, but the threads are designed to fit more tightly together. Technically, this connection doesn't need sealant (the first time), but one you have tightened the fittings the threads become deformed, so anytime you disassemble a connection and reassemble it again, sealant will be needed.

Almost everyone I know uses sealant the first time and every time, just to be sure.

Out of curiosity I just checked Tractor Supply Company's website for hydraulic fittings, and hoses with factory ends. All of them, from 4000 psi down, are listed as NPT. I'm assuming they are, in fact, only NPT and not NPTF, but I don't know. If the distinction was lost when the descriptions were written, that would be a pretty big error.

 

[J_J]

Another point of interest would be that NPT fittings were never designed to be used over and over as there is some compression and distortion every you tighten the fittings.

That includes the NPT crimped on hose fittings. So if you notice them leaking, you can try tighten them down and use paste or replace them.

If y use anything like a lubricant, the torque figures will not be correct.

Torque figures are for dry contact.

So what happens if you mix the two type threads?

Is each fitting identified as to the NPT or NPTF?

OK, who started this bag of worms.

No wonder the NPT stuff is leaking more, we don't even know what we have.

Now that the threads are mixed/combined and tighten, what do you call the mixed up threads now? What a bunch of crap.

 

[CJONE]

Another point of interest would be that NPT fittings were never designed to be used over and over as there is some compression and distortion every you tighten the fittings.

That includes the NPT crimped on hose fittings. So if you notice them leaking, you can try tighten them down and use paste or replace them.

If y use anything like a lubricant, the torque figures will not be correct.

Torque figures are for dry contact.

So what happens if you mix the two type threads?

Is each fitting identified as to the NPT or NPTF?

OK, who started this bag of worms.

No wonder the NPT stuff is leaking more, we don't even know what we have.

Now that the threads are mixed/combined and tighten, what do you call the mixed up threads now? What a bunch of crap.

+1 completely agree. Just like everything else, it is getting so messed up you can't accomplish anything without a bunch of grief. CJ

 

[SPYDERLK]

Another point of interest would be that NPT fittings were never designed to be used over and over as there is some compression and distortion every you tighten the fittings.

I find NPT fittings to get better with use, esp if used with sealer repeatedly in the same hole. I believe many taper threads arent quite round off the production line due to the cutting flutes on taps or dies used to cut the threads. The worst ones are difficult to seal and need to be burnished in to the mate. A problem fitting set can often be corrected by using anti seize in the joint and tightening moderately -- and then rotate back and forth from this position ~1/8 turn several times. Disassemble, clean, and reassemble using tape or sealer.