I've got a 329D boom cylinder that is leaking. I tore it apart and repacked the cylinder and it lasted about a week and it's leaking again, slow drips. I've rebuilt dozens of different types of cylinders and I'll say this internal locking ring cylinder is the most difficult I've ever worked with. I had issue cutting a seal while putting it together, luckily I had order 2 kits so I was able to put it together again. I had a heck of time getting the primary piston seal expanded and on and then had to let it set 30 minutes with a hose clamp trying to shrink it back up. I had a mess getting the locking ring in, I tried the hose clamp ring trick I found to no avail. I ended up just putting inward pressure on the gland and working the o ring in with a brass drift. My questions is are these problematic to get to seal? My dealer will do it for $225 plus parts but he says 10 to 14 days without the machine. I'm also a more hands on person and typically like to fix it myself but I don't want to keep wasting time and money if they are super difficult to get a good end result. I suppose I could order a new piston, there were rubber components on the piston that were non serviceable, could this be the issue? Any advice would be greatly appreciated.
DAM! Most of us could do it in an hour. Is this a coated piston? If material was coming off of it then it should have been replaced. It will contaminate , not only your cylinder, but the rest of the hydraulic system as well. Sounds like you are in a learning experience. The first 1 is ALWAYS a B*&^%. After you learn the tricks its relatively simple.
It's not a coated piston, it has what looks like a couple of telon (maybe) rings that are made into the piston that are non serviceable.
The piston rings should be serviceable. If this is the type where the gland needs pressed inward to remove the snap ring, the kit should have a plastic filler that temporarily sits in the snap ring groove, to allow the gland to pass. It is then removed, and the snap ring installed.
The orange ring is the temporary filler.
Pic of piston?
Yes, the kit has the filler , took awhile to figure that out the first time. There is an O ring and a backup O ring that go dead center in the piston then a black ring that looks made on that is on either side if memory serves me right. I might tear it down again I guess, I have the parts and it's not a huge deal just a PITA if it still leaks and I have to take it off a 3rd time and have it built. I feel like I'm missing something with this style of cylinder and I just can't quite put my finger on it.
Its not made on. Its the one piece piston seal that is heated and stretched into position, then compressed in place for install. There will be a one piece rubber expander under that. 2 plastic guides go on each side of that seal assembly
So the center seal is supposed to be heated up before installation? Like in warm water or something? Then the 2 plastic guides that is what I'm saying does not look serviceable, they are not in the kit for sure. Do you have to order those separately?
Take a pic of all the seals and the piston. I need to see what you are working with
https://www.herculesus.com/product.php?productcode=JD-AH160647&pd=Y&pid=627765
Perfect!
Ya that's the deal so the non metallic bearing is non serviceable.
Correct. That is bonded to the piston
There is a picture of the piston, that orange ring in the middle is a real problem to get on, by the time you stretch it on, it's too big to fit in the bore, I cut the first one in half. Are you saying to heat this up somehow before installation ? I think I see why it's leaking again, the white o ring on the gland must of been cut going back into the tube. It's a reallllly tight fit, any suggestions for this (yes it's lubed to beat the band). Also the snap ring any suggestions on how to get that thing back in?
Those were always a bear to fight with (and I was always hoping for an easy fix to come up). Was told to just soak those in really hot water until they were a little more pliable and fight it on. Once they were stretched on and oversized, would wrap with piston ring compressor or cut up 2 liter bottle plastic and tape to push it back into form.
Dump the complete piston assembly in some really hot water while doing it.? The seal will likely go back into shape faster if it's hot.
We'll I came up with a trick that seemed to help quite a bit. It helped me get the gland seal in evenly and more important it made that awful snap ring about a 30 second job. I took a piece of 2" drain pipe cut it down the center and clamped it onto the cylinder. Then I threaded a ratchet tie strap thru the cylinder eyes and it allowed me to put pressure even pressure on the gland. On the snap ring once I had some pressure on the gland I just worked it in a little and the gland popped in. I ran the machine about 10.5 hours over the weekend and so far it's still dry, hopefully I have it repaired.
Congrats...they can be a pain, I use a little white lithium grease on all the seals going back in. When installing the rod and piston end, I rotate and wiggle it side to side while going in with it. Lubrication always helps.