Teflon or thread seal on hydraulic hoses?

[Zephrant]

I'm new to hydraulics. I bought a hose/fitting/gauge to measure my bypass pressure, but am not sure if I should use some kind of a thread seal when assembling them. I'm used to using teflon tape, or the pipe joint compound as needed, but that is on low pressure stuff.

I don't want to put the threads together dry- what should I use?

 

[groundcover]

I would check with the place that you got them but it seems that the industry is going back to thread seal as the tape was causing problems. Some of the hydraulic fittings don't need either,Wayne County Hose might chime in here and give some insight.

 

[Willl]

Loctite 545

 

[RickB]

Tapered pipe threads require some type of sealer/tape. Either is fine when used correctly, either can be problematic if used improperly. Other fitting styles such as inverted flare, JIC, ORB, and ORFS do not require any sealer/tape at all.

 

[Zephrant]

Thanks all- these are NPT threads, similar to what I use for water applications which is what concerned me. There is no flare or O-ring that seats.

Does anyone else prefer the thicker red teflon tape instead of the normal stuff on the blue rolls? I think it is sold for gas applications, but it is easier to handle so I use less wraps- usually two.

 

[kennyd]

You should use a Teflon based PTFE paste. Tape, if not used VERY carefully can find it's way into the system and cause problems.

 

[Kfbeal]

We've used the white Teflon tape on the blue rolls for the 25 years that I can remember on hydraulic systems without any problems.

 

[DieselPower]

Paste or tape both work fine. Just make sure you don't get any on the tip of the fitting otherwise it can get into the system.

 

[Zephrant]

Thank you all- The Loctite looks like it will seal up the connection, but make it hard to get undone. I'll pick up some paste when I can, but for this gauge hose the tape should be fine.

Next question then, how tight? I normally go pretty snug with a pair of standard box wrenches (maybe 7" long). I'd rather be loose and snug it up to stop a leak then too tight and destroy the fitting. (Not that I've ever done that )

 

[CurlyDave]

Next question then, how tight?

I have always gone about as snug as I can reasonable get it with a pair of open end wrenches (not adjustable just plain old fixed open end). It should not require heroic effort to take it apart.

With the thin teflon tape, the correct technique is to leave the first thread exposed, and only use 1 1/4 to 1 1/2 wraps of tape. A lot of people use way too much.