View Full Version : Non-teflon thread sealant

11-07-2009, 03:24 PM
Putting my log splitter together, the hydraulic cylinder and control valve both said to use thread sealant without teflon. Well, I had two kinds that both had teflon. The only one that didn't was call Leak Lock. Since it said it was alcohol clean up, I assume it is a shellac based goop.

Well, it aint worth much, half of the joints I made up leaked. All were 1/2" pipe threads, nothing unusual, but it's gonna be a mess to take all these lines apart, drain the fluid out to re-install.

So, what's the deal with teflon and hydraulic fluid? I've seen it used for fuel piping, and of course water. What would be a good pipe dope for this fluid?

J. R. Williams
11-07-2009, 03:47 PM
One old stand by thread sealant is a mixture of Litharge (Lead oxide) and Glycerin. The threads must be clean and the compound sets up in a hurry.


11-07-2009, 03:51 PM
I have a lot of hydraulic connections on my tractor and use teflon paste sealer. I have heard a lot of warnings not to use teflon tape but not paste. People do use tape but it must be done carefully because it can ruin a pump quickly.


Peter N
11-07-2009, 04:03 PM
The only problem with using PTFE tape in an hydraulic system is that there is a possibility that small pieces of tape can enter the system, and possibly stop a spool valve or similar from sealing in the open or shut position.
Obviously in some cases this can have disastrous consequences, hence the general recommendation against it, particularly if people wind it on the wrong way, or across the end of a fitting.
However, I don't see how small tape debris could damage a pump in any way, it would just be pulverised.


11-07-2009, 05:04 PM
When I was trying to do some exotic stuff, I bought one each of all the threadlockers these guys make:


Their web store is at:

The have shellac based thread seals as well as special ones with big chunks for damaged threads etc. More kinds that I've seen elsewhere anyway.

Hope this helps if you're looking for odd thread sealers. No relationship to me, I just bought some of their products once.


11-07-2009, 05:16 PM
Loctite 569.

11-07-2009, 06:18 PM
The loctite products are excellent. Paste with teflon is also excellent

The problem with teflon tape is that it flows, in terminology. Probably a better explaination is that is squirms out of a joint when there is pulsing pressure. Diesel fuel will seep out between the tape, as will warm hydraulic fluid.

If you are using taper fittings for hydraulic high pressure they should be a high quality, reliable brand like Parker,etc. Standard american pipe fittings are only good for return lines.

11-07-2009, 06:38 PM
I would recommend Gasolia pipe dope. We used to use it on gas station nozzles and it is gasoline and diesel proof. It does set to a point. I would say it is "semi-hardening" over time. It remains somewhat flexible yet seals quite well.

Oh...and quality threads is critical. I have never had good luck with higher pressures in cheap die cut pipe threads.


11-07-2009, 08:21 PM

11-07-2009, 08:27 PM
I use loctite 567

11-10-2009, 12:46 AM
i use permatex aviation form a gasket, on every thing ,car head gasket,oil and water pump, pluming,and anything else aroun here .works great F me .