Quick question about cylinder teardown

[Dieselmh]

Dad needs to rebuild one of the cylinders on his little Kubota 4690 backhoe. He's having a problem getting it taken apart though, and I can't get out there for a few days to help. This is the best pic he sent me, but it's a little blurry so bear with me.

He has already made a pin spanner/gland wrench that will fit the holes in the nut (you can see one hole in the pic, the other is on the other side of the rod.) The question he has is about the small square pin that you can see on the left side of the cylinder. He can tap that in either direction, but it won't come out. Is it just some sort of lock? Should it come out, or just move to one side? He says that the nut seems pretty tight, and even after getting a couple of complete turns out of it, it doesn't appear to have moved. I'm thinking that it's just a fine threaded nut and is going to take a bunch of turns to get it out, but I don't know if that pin needs to be moved/removed somehow to keep from messing up the nut. Anyone torn one of these down before that can tell me how to do it? I know it can't be that hard, but this is one of those times where trial and error could turn out to be really expensive.


And no, that's not pitting on the rod, that's where the fluid leaked out and it got some sand on it. I already asked him about that. :laughing:

 

[cowski]

the square pin has to come out.take a screw driver and pry it up then pull it out with a pair of vice grips.it is a locking ring.

 

[Dieselmh]

the square pin has to come out.take a screw driver and pry it up then pull it out with a pair of vice grips.it is a locking ring.

That's what I was looking for. Thanks! He said it would move back and forth some, but not come out. I doubt that he tried to move it up and down while trying to remove it though. I'll tell him to give that a shot.

edit: Any other ideas, that didn't work. The pin doesn't come out. When he slides the pin one way, the part with the holes will spin freely, but doesn't unscrew or pop out. When he moves the pin to the other side, the part with the holes will get tight and "lock" into place. No combination of pin placement will allow the pin to come out and there is no "up and down" movement in the pin at all. Anyone else have any ideas?

 

[Dieselmh]

Well, just to update the thread, he got it out. Cowski was 100% correct, it just took two people to do it. I don't know if they're normally that hard, or if it's just because of the age of the thing, but it was tough. After Dad finally found a hydraulic shop that would let him talk to a mechanic, they give him some tips. Had to clamp on to the pin with vice grips, use a hammer/chisel to tap it from the other side while pulling on the vice grips, and had to use the tool he made to turn the end cap counter clockwise while pulling on the pin. I guess since the keeper ring touches the end cap, turning the cap helps to unwind it from the cylinder. Anyway, thanks again cowski, you were right, we just weren't putting enough "umph" behind removing the pin. :laughing: