Leaky hydraulics at the cylinder

[rossn]

Bought and assembled a new snow plow, and have a fitting at the raise/lower hydraulic cylinder that leaks at the 3/8" fitting. I used permatex thread sealant with PTFE (as per Massey Ferguson instructions), and even after disassembling and re-assembling with fresh thread sealant, it continues to drip a drip or two per minute. I've cranked on it pretty good with a 12" crescent wrench, and wouldn't want to push it further. Is this a common issue? Is there a specific time required for the thread sealant to set up before use?

 

[kennyd]

I assume this as an NPT style fitting? Sometimes if they have been reused they will always leak, remember the threads re slightly crushed every time they are tightened. Sometimes they are just poorly made and will never seal either. Generally the sealants used will take 24 hours to dry to full strength, but that doesn't sound like your issue.

 

[CCWKen]

Have a photo of the fitting? Perhaps it's supposed to have an O-ring.

 

[rossn]

Thanks - I'll take a pic tonight and see if I can see specifically what area of the fitting or joint is dripping. If I recall correctly, it is a 3/8" male fitting - so if there is an o-ring (missing), I'm guessing it is on the cylinder side. I believe it is NTP.

 

[rossn]

Here's a photo of the fitting. It is actually the lower fitting that is leaking, though they are the same.

Regarding the comment about threads being worn each time you tighten them (and the second time I cranked on this pretty good), one pair of the hoses that came with one of the cylinders looked like it could have been used. When you look at the fittings, they have a dull/blackish finish, versus the other ones that have a bright/clean finish. You can see this in the picture. Perhaps these hoses were used before.

 

[kennyd]

Here is another wild guess, but one is not leaking so maybe this is not it: The ports on the cylinder are ORB (o-ring boss) and the hose is NPT.

Although I generally recommend against it, you could clean the fitting well and apply about 3 wraps of teflon tape starting at the second thread from the end, then apply your PTFE paste.