JD 300 Backhoe swing cylinder repair

[RCBS]

Have located the seal kit. This is 100% brand new for me as I have never had a cylinder apart. Removal from the machine is not a good option, so need to repack it in place. Been leaking for two years and can no longer be ignored as the leak has gotten worse.

Open to any tips/tricks/advice if you have some.

I can't locate a dummy guide. This is the best I have found so far but is a different design of cylinder end.

 

[1Snowcat]

 

[1Snowcat]

Looks like a real stout air chisel was used in the video above if the end cap has notches similar to the one in the second video. I think the tear down is toughest part.. along with keeping it super clean upon re-assembly.

 

[RCBS]

It is a notched cap. Plan to use a big center punch and a 3lb hammer. As much oil as it has been bathed in I'm hoping it doesn't fight too much. I see mentions of a taper pin or some sort of lock ring that is giving me the anxiety. I am assuming that once taken apart the gland packings will be self explainatory. Getting everythng back in correctly is also a bit worrying. Probably a good idea to get a plug for the feed line while it's disconnected? (wondering if gravity will try to drain off everything above through it) Yep, complete noob on hydraulic systems. Familiar with fittings and hoses and that's about it. I put this chore off all last summer due to my ignorance. It's getting fixed one way or another this year. I'm pretty good at digging up source material but this gal is nigh on 50 years old now and not much talked about here on the mighty interwebs.

Thanks to those who responded so far.

 

[1Snowcat]

I wouldn't worry too much about saving the fluid above it, with a plug, as it's not really not worth saving, it's used oil, and and more than likely needs changed anyway, fresh fluid is best especially since you are going to the trouble to rebuild the cylinder, and as much pressure the system makes, its a self bleeding system. The hammer and punch method MAY loosen the threaded ring (remember righty tighty, lefty loosey) but its more than likely pretty FROZEN due to RUST/Corrosion, dirt and gunk etc, especially being so low on the backhoe.. I've found the rapid tapping of an air hammer tears up the metal ring less than beating on it with a hammer and a punch, its the rapid action of the air hammer or electric hammer that starts it turning. Borrow one from a friend if possible. Don't overthink the packing, take pictures of the old before you take it apart (best part about new phones) and its going to go smoothly. If you get the area clean take pictures and post em here (before and after), people on here are great at helping!

 

[1Snowcat]

Pressure wash the area before you tear it apart is a HUGE help IF possible (a cheap degreaser is MEAN GREEN or PURPLE POWER wear gloves) both available at Wally World , just DONT USE WATER after the system has been OPENED UP! Solvent based cleaners are best even cheapo mineral spirits, or diesel fuel, gas or white gas/kerosene) as a solvent is better than WATER after its been opened up to avoid rust. My cousin works in a hydraulic repair shop, I've spent lots of time helping horse around BIG cylinders. OLD junk cotton t-shirts are excellent rags for cleaning up the area mopping up all the oil and gunk.. Goodwill sells t-shirt rags boxes for ultra cheap too..

 

[1Snowcat]

use a hydraulic compatible grease to re-assemble, or hydraulic fluid on all the seals you re-furbish makes it go together smoother than DRY..

 

[1Snowcat]

they always used white lithium grease in the tubes from NAPA etc for re-assembly or better yet Aero Shell grease but its not cheap

 

[1Snowcat]

The lock/snap ring might be inside, below the lock ring, if that makes sense, (remove the notched ring which allows access to the lock ring (protected by the notched outer ring) a big set of internal/external snap ring pliers to remove, unless its just a round snap ring without the eyes on the ends, then a sharp pick rather than the pliers..

 

[RCBS]

I wouldn't worry too much about saving the fluid above it, with a plug, as it's not really not worth saving, it's used oil, and and more than likely needs changed anyway, fresh fluid is best especially since you are going to the trouble to rebuild the cylinder, and as much pressure the system makes, its a self bleeding system. The hammer and punch method MAY loosen the threaded ring (remember righty tighty, lefty loosey) but its more than likely pretty FROZEN due to RUST/Corrosion, dirt and gunk etc, especially being so low on the backhoe.. I've found the rapid tapping of an air hammer tears up the metal ring less than beating on it with a hammer and a punch, its the rapid action of the air hammer or electric hammer that starts it turning. Borrow one from a friend if possible. Don't overthink the packing, take pictures of the old before you take it apart (best part about new phones) and its going to go smoothly. If you get the area clean take pictures and post em here (before and after), people on here are great at helping!

I just relapced the hydro pump about 30 hours before this cylinder became a major problem, so the fluid is new after that system flush. I don't have any air to work with where the beast is. I understand that the cylinder is fairly simple and that's where I am usually able to screw something up. I tend to go into this stuff apprehensively on purpose trying to make sure I don't goof it up. I did degrease and pressure wash the area last fall. (as far as I made it) It was an absolute mess (had some lever valves leaking for a few years above it) and even though I don't mind getting dirty it was beyond the pale. Penetrant was applied liberally to the entire area with focus on the outer swing pins after washing. Come to think of it, I need to hose it down some more. Examining the lock ring it looks like a cold chisel was applied the last time it was open. My backup plan if I cannot hamer it loose is to see if I can get a 48" pipe wrench onto it. I'm hopefull that the absolute bath it had been taking in fluid has kept corrosion to a minimum. It does sit out, but honestly doesn't show much rust at all.

Thank you and others for the tips. It's all being taken into consideration.

 

[1Snowcat]

Good luck, keep us posted! Some pictures before and after are a great way to reference what it looked like before taking it apart.

Post some pictures here if you need help.

 

[RCBS]

Here she be. Gave everything more penetrating oil. Unsure as to when I will attempt teardown. Got a bunch of the usual spring chores to knock out first.