FEL squeal under heavy load

[VT_Hokie]

Well I think that I finally broke it. I have a grey market Yanmar with a no brand FEL that I was using to dig out and push down some small size trees. In doing so on one particular tree, the left cylinder used for raising and lowering the FEL started to squeal. Now I have up and down movement but no strength to hold the bucket under heavy load. When I raise the bucket it will go up then drop about an inch or two and stay steady. With it up I can put my weight on it (200lb) with out it drifting down. The bucket will rotate, but like the arms not under heavy load. I am assuming that there is a pinhole leak around the piston in this cylinder in the ring? or gasket? Could it be a slightly bend shaft or some type of scoring inside?? I was thinking of pulling the unit and taking it to a local shop as I am good with a wrench but have not worked on hydraulics before. Are there any specific precautions before pulling the cylinder? I am assuming FEL on the ground, power off and slowly undoing the connectors....

Thanks in advance

VT

 

[Soundguy]

If it is a da cyl, pull the outlet hose and see if the cyl is bypassing with a load on it..

soundguy

 

[Wayne County Hose]

I've never done a gray market Yanmar cylinder, but loads of common ones. Most I have seen have a one piece piston,nut combo. The piston rides very close to the cylinder wall and has a 2 piece piston seal with a wear band on either side of the seal. Internal o-ring, and an external square ptfe ring that rides the cylinder wall. It is possible that the nut/piston assembly came off, but I would suspect internal damage if that did occur. I can not see it having any kind of pin hole, it's either blown out, or okay.

If you're pretty good with a wrench, take it off and rip it apart, I don't think you can damage it any more than it is. If it has the cap I think it does, spanner wrenches can take it off, maybe. I have the proper spanner wrenches and hit them with a 3 lb ball peen and they still won't come off. I end up using the same hammer and a big chisel to break it loose.

If it were my tractor and you reseal one side, I would do the other side also as they are sister cylinders, the other side may not be far behind. Good luck.

 

[Villengineer]

The bucket will rotate, but like the arms not under heavy load. VT

This statement leads me to believe that you may have a relief that is stuck or damaged somewhere in the system. It could also be a bad seal(s) in the loader control valve. If your left lift cylinder blew it's packing it should have no affect on the bucket curl function. You might want to check your 3 point system to see if it's operating correctly. If not, it might be your main system relief.

 

[VT_Hokie]

The three point system is working fine, no problems there. If I have the tractor on a level spot and the FEL flat on the ground, it will not lift the front of the tractor up with the main arms. Same problem if I curl the bucket under, not enough force to raise the front. However it is able to maintain position driving around. Did this while raking for a couple of hours. I will take a closer look at my system and see how the hoses are running. I have a two stick system, would there just be one release valve or two? Though it was strange for the bucket to loose power if it is on a different system...With the squeal in cylinder under load ,it kinda leads me in that direction but I will see if I can locate the valve and maybe give it a rap or two.

Thanks

 

[Harry c]

Sounds like a problem in the valve or Pressure Relief Valve, most likely the PRV. The valve probably has load checks that are stopping the loader from dropping any more than the first 2 inches or so. If the curl function is acting up as well, it's almost certain it's not the lift cylinder. I don't think I've ever heard a cylinder squeal. Lots of squeals from PRVs though.
It's entirely possible that the FEL and 3 pt have seperate PRVs. It's quite probable if the FEL is an add on. It's extremely unlikely you would have different PRVs for the lift and curl.
Sounds to me that you've got a chunk of junk in the PRV or a broken spring...

 

[SPYDERLK]

The three point system is working fine, no problems there. If I have the tractor on a level spot and the FEL flat on the ground, it will not lift the front of the tractor up with the main arms. Same problem if I curl the bucket under, not enough force to raise the front. However it is able to maintain position driving around. Did this while raking for a couple of hours. I will take a closer look at my system and see how the hoses are running. I have a two stick system, would there just be one release valve or two? Though it was strange for the bucket to loose power if it is on a different system...With the squeal in cylinder under load ,it kinda leads me in that direction but I will see if I can locate the valve and maybe give it a rap or two.Thanks

A puzzler. I agree completely with Villengineer. Since your 3pt works 'ok' I think you have a problem in the loader valve and you are not lifting enuf with the 3pt to notice a downsteam effect that is actually there. I cant understand the squeal in the left cyl. I would predict a problem with the loader relief valve. It could be that the sound originates at the relief but manifests in the left cyl - resonances and such. Stranger things have happened.
larry

 

[VT_Hokie]

Well tomorrow is suppose to be nice so I will break out the wrenches and let you all know what I find..

Thanks,
VT

 

[Harry c]

Put a pressure gage in the system and see what pressure you're getting. That would eliminate the cylinder. There are several theads on setting up a simple gage.

 

[petegoud]

I agree with Harry, install a pressure guage inline (incoming line to valves). I installed one to when I was trying to determine why I could only raise the loader empty. It turned out that I was only building a few hundred pounds pressure. In my case, it turned out that a small piece of debris was holding the relief valve partially open. A byproduct of installing that gauge is that you can monitor the hydraulic system closer, and also see the weight of anything you load. Doug