Jinma 354 backhoe hydraulic problem

[crofutt]

The backhoe on my 354 developed an odd problem suddenly the other day. As I was taking the last "bite" of digging a very long ditch the boom would raise very slow and actually I have to help it to get it all the way up. Plenty of power in the down motion, just the up. I switched the hydraulic lines and of course the lever was reversed but same problem. I think it points to the cylinder but before I yank it off and send it somewhere I thought I would ask to see if anyone else had a similar issue. Thanks!
Bill

[RonMar]

I think your suspicions are correct and that it could have a seal torn on the piston. The boom lift is probably the most stressed as it is lifting the structure and whatever is in the bucket. The same action having the problem with the hoses reversed pretty much confirms that it is in that cylinder. Hot fluid after a long workout could also be making ths problem more evident.

I would also reccomend that you check your relief pressure. Since this particular cylinder is under so much stress, an over pressure condition from the valve could also have shortened the piston seals life and could ultimatly damage other components.

Good luck.

[crofutt]

Thanks Ron, I had the cylinder repaired locally a couple years ago after the welded-on pressure line sprung a leak. Maybe it was something they did/didn't do but they charged 250 or 300 bucks which I thought was a lot. I am leaning towards a new cylinder. Anybody know where I can get one?
Bill

[Bob Rooks]

The newer cup seals are opaque and stronger, not black rubber. I had the same problem on boom & jib cylinders. The Chinese rubber does NOT like synthetic hydraulic oil.

If you get a new cylinder, expect the same seal longevity unless it has the new style seals in it.

I solved the whole problem and went with the LiTW hoe. Nice and smooth.

[SPIKER]

You may also be able to switch the boom up cyl to the bucket curl cyl. I've had to do this to fix broken rod ends, (swapped them around made new rod ends then welded them on using the boom (elbow position) as a welding jig. I haven't had any seal issues but have broken 2 rod ends, (waiting for the 3rd one to break now lol have a NEW rod end waiting for it already home made ones work great vs the factory cheap cast ones...)

mine is JW03 though so may be different than yours...

mark