Pipe dope on hydraulic line connection?

[nbennett]

My neighbors tractor has a hydraulic line leaking at a connection around the threads. the connection is very tight. Can pipe dope or another material be used to seal this? The fluid is UDT.

 

[JDeerekid]

good amount of tephlon tape should do, just make sure you start back a couple treads from the end so to not get any tape in the hydraulic system. Worked for mine. Also there is a special pipe dope out there just for hydraulics, if I remember right it is black or gray color. My local tractor dealer used it on a inline filer setup for my wood splitter and it worked nice. I never did find out what brand it was. hope this helps

 

[nbennett]

Thanks. The reason that I asked is one time I tried Teflon tape on some connections where automatic transmission fluid was used for hydraulic fluid. The teflon tape was quickly dissolved and every connection leaked.

 

[59ih340]

I had the same problem with a large fitting,I used teflon thread sealer from permatex and it's held up fine.

 

[Sherweld]

It's not clear what type of thread we're discussing here

Pipe thread (tapered) is generally the only one where tape or better still, dope would be recommended. Other types of hydraulic fittings seal by other methods. (tapered seats, "O" rings, etc)

 

[TedLaRue]

I think Sherweld is shrewd. I'll elaborate on his/her post a bit.

The fitting could be

1. tapered "iron pipe threads" (IPT)
2. butt joint with a soft copper/aluminum washer
3. "banjo fitting" with soft copper/aluminum washers
4. a joint with an o-ring

For #1, Teflon tape or pipe joint compound might help.

For #2 and #3 above, tightening might help, or you could replace the soft-metal washer. Or if you're desperate, try flipping the washer over. Or you can get a new washer at a NAPA dealer or local car parts dealer.

For #4, the only solution is to replace the o-ring. You could get one at your dealer, but you might find one at a big-box (like Lowe's or Home Depot).

I haven't found it necessary to use tape or dope for any of my hydraulic line joints. But if a previous owner has over-tightened fittings or otherwise distorted them, you could have some problems.


Be aware that over-tightening can distort a fitting and cause it to leak!

 

[ultrarunner]

I use LOCTITE 567 Thread Sealant when needed.

Used in the chemical processing, petroleum refining, pulp/paper, waste treatment, textile, utilities/power generation, marine, automotive, industrial equipment, gas compression and distribution industries. It is also recommended for industrial plant fluid

As with any sealant, paste or tape, care must be used to insure the material doesn't contaminate the hydraulic system.

 

[davey4000]

I had a connection that leaked and I used white teflon tape and later teflon paste. It still leaked. I then used the yellow gas line type teflon tape and it fixed it right up. No leaks. These were npt fittings.

 

[EddieWalker]

I've never come across a hydraulic fitting that required teflon tape or a thread sealer. The preasures on the line are so great that they require a new o-ring or special washer. Most of the ones I've dealt with have all been sealed with O-rings.

Eddie

 

[Sherweld]

I may have the wrong idea here, but the main reason that I use either teflon tape or dope on tapered threads is not so much for sealing, but the ability to take the joint apart in the future if need be. The taper tightness and the micro pores in the thread metals and particularly rust can make many joints a real trick to take apart without damage.

I only say this because I'm old enough to have had to take apart many joints over the years .....