Hi all I recently put new seals in the dipper arm cylinder of my excavator. Today was the first day I ran it properly since resealing. There is a small weap of oil coming from between the gland nut and cylinder barrel. I guess the oil is bypassing the o ring seal on the gland nut. I used a genuine seal kit and made sure to use plenty of lube when reassembling the cylinder and also followed the workshop manual. It is a threaded gland nut that is on the cylinder, not a cap with a ring of bolts. If I was to unscrew the nut halfway, and apply thread tape or compound, and tighten the nut again, would you think it would seal it up? Thanks
Some cylinder glands used a o-ring just under the gland lip as a dirt protector. Not sure if yours was designed that way but your idea should work as long as the perimeter o-ring wasn't damaged when you installed the gland back into the barrel.
Thanks for the reply. Ya I suppose I wont know if its damaged or not until I unscrew the gland a bit. I was very careful to keep everything straight and used plenty of lube to prevent the o rings getting damaged, so hopefully it's ok.
any sharp edges inside the barrel can nick an o-ring. they need to be smoothed before installation of the gland in the barrel
That’s a good point about the dirt protector! It might be worth checking if the workshop manual specifies an extra o-ring in that area. If not, the thread tape idea seems like a decent workaround - just make sure the threads are totally clean before applying it. A nicked o-ring could definitely be the culprit, though.
That’s the best approach - care and lube usually do the trick! If you decide to unscrew the gland nut on the hydraulic cylinder try inspecting the o-ring for any small tears or flattening. Sometimes, even a slight imperfection can cause a leak under pressure. Are you using a specific type of lube for hydraulic seals, or just a general-purpose one?"
Great tip about checking the o-ring! A small flaw can definitely cause big problems under pressure. As for lube, I’ve been using a silicone-based hydraulic seal lubricant it’s worked well for me because it doesn’t degrade the rubber over time.
Arthur, Mike and Steve . . . Almost like a AI trio . . . Can you guys sing?
Why do say so?
Arm all the way out and pop the pin out of the rod, undo the gland a bit, sip the oring over the end of the rod and then down over the gland and screw back up, near seating sometimes you need to go back fourth slowly as you do it up to left the oring move and seat properly or they can pinch and tear, some thing happens with oring boss fittings and valves especially
Make sure oring isn’t twisted as you roll it on the gland. Run a seal pick around it in a circle under the oring. This will un twist the oring and look for the moulding seam.