hydraulic leak at the lift arm

   / hydraulic leak at the lift arm #1  

NorTracNY

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I have a hydraulic leak with my Jinma 254. The leak at one of the lift arms. I removed the lift arms and I see the bad seal, but I can't figure out how to get the parts out. See the picture here.

http://johnstractor.homestead.com/files/HydPowerLift.jpg

I took off both lift arms and removed the two screws (53), but I can't get 36 or 37 out from either side. Can someone with a little more knowledge than me help?
 
   / hydraulic leak at the lift arm #2  
This should not really be a issue unless the seal is really shot. You have the hydraulic fluid level too high, that is you main issue.

You check equipment with thread in dipsticks by not seating the dipstick to do the check. You simply unscrew it, wipe it off, then place it in the hole without threading in, then pull out to check.

By doing this properly you will raise you fluid level 1.5" or so. The seals are just there to keep water, debris, and the splash of hydro fluid out.

I agree you need to fix the seal but if you did not have it overfilled you probably would never know its leaking.

Chris
 
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   / hydraulic leak at the lift arm #3  
I have not replaced these seals before but I just finished replacing some seals in the front axle knuckles last week. There were metal rings inside the seals and the seals were so tight fitting in the bore that I finally had to take wire cutters and nibble completely through one side of the metal ring to pull it out. The replacement seals were nowhere near that tight.
 
   / hydraulic leak at the lift arm #4  
That seal looks like a standard spring-assisted cup seal in the drawing, so you just hook it out with a small hook probe, or (worst case) you poke a hole in the metal shell with a sharp prick punch, drive in a sheet metal screw and yank it out. However, if it isn't leaking so much that it is costing you money to replace what it leaks, then I'd ignore it until it gets really bad - the leak is flushing any dirt out, so no damage will occur. Having to cut one of those seals to remove it is very common, by the way. At the factory they are often installed with a bit of sealant or shellac on the edge to seal them and that sets up like glue. When you replace the seals, if they have a bare metal rim it should be coated with a sealant prior to installation. Some new ones have a sealing coating applied at the factory and some don't. I always seal them in any case, so they don't leak and can't spin in the bore. If yours went in too easily they may leak around the outside unless sealed with a coating.

As for overfilling your lift box sump, that could be a problem, but NOT if you have screwed in the dipstick. Everyone seems to say that if you do that you will end up overfilling the sump, but actually the opposite is true. If you think about it, screwing in the dipstick puts the line on it lower than if you just rest it on the cover. That would mean that your fluid would reach the line at a lower level than if you simply rest the plug on the cover, which puts the line higher than it is when screwed in. Not meaning to jump on Chris, but I've seen this same statement so many times that it drives me nuts and I finally had to say something.
 
   / hydraulic leak at the lift arm
  • Thread Starter
#5  
Thanks for the replys. No it is not overfilled. It leaks only when the tractor is running. The seal is obviously damaged on the side which is leaking. It sounds like I need to destroy the seal to get it out. How would the parts behind it come out then? Is it just that the seal is holding everything in with some sealant? Is there a certain sealant I should ask for at the auto parts store?
 
   / hydraulic leak at the lift arm #7  
Thanks for the replys. No it is not overfilled.
That's a matter of interpretation. All 4 of my Chinese tractors had only one line on the hydraulic fluid dipstick. I initially interpreted that line as the LOW fluid mark. I got tired of cleaning up the mess behind/beneath the tractor due to the constant spewing of fluid out the fill vent holes. When it eventually quit, I noticed the hydraulic fluid wasn't registering on the dipstick anymore. So I reconsidered that line as the FULL mark. From that point on I only added fluid when the dipstick came out dry, and took care not to fill any higher than that one line. Pretty much ended the issue with spewing hydraulic fluid.

That said, lateral motion will necessarily cause fluid to splash against the upper lift arm seals - especially when the fluid level is high. Leaking seal(s) should not be ignored. But Chris does have a valid point about the actual checking of fluid levels on Asian equipment. When the dipstick is not threaded, remove/wipe/push all the way in/remove/check/replace. When the dipstick is threaded, remove/wipe/set in hole/remove/check/thread back in.

//greg//
 
   / hydraulic leak at the lift arm #8  
Yes, you are right Rich. Checking in this matter will raise the level 1.5", not lower it. I guess what I was trying to say is that no matter what the level of the fluid should not be so high that its leaking out around the lift arms.

It was a issue of knowing what I wanted to say but it not coming out of my mouth or keyboard in this case properly.

Chris
 
   / hydraulic leak at the lift arm
  • Thread Starter
#9  
There is a set screw on each side of the lift arm that you must take out, there are 2- seals on each side.Look in your parts book if you have one

Tommy
Affordable Tractor Sales
"Your Jinma Parts Superstore"
Home of compact Jinma, Foton, and Koyker Tractors and Parts, Wood Chippers, Backhoes - Affordable Tractor Sales Company

As mentioned, I did remove both screws (#53). I take it I just need to destroy what is left of the seal that is leaking. I worked on it for a minute or two this morning. I appears to be glued in pretty good. It's obviously deformed unlike the side that does not leak. I also had a metal ring that covered the seal on the side that leaks, but not on the other side. (Left side is the one leaking) Should there be a extra metal ring? I don't see it in the parts manual.

Yes, I'm sure it's not overfilled. Using the tractor just once leaked enough that the stick is dry when screwed down.
 
   / hydraulic leak at the lift arm #10  
Chris,

I know what you mean - I had to re-write my little rant twice to get it to sound remotely sensible. At least, I think it ended up sensible. :laughing:
 
 
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