Loader Control Valves or Cylinder Failure?

todintexas · Sep 27, 2023

You guys have helped a bunch in getting this old tractor back up and moving to help around the place, just want to say I appreciate that. Tractor is a 1971 Ford 3500 series, diesel with backhoe attachment and front end loader. Yesterday, we experienced some sort of a failure in the lift arms for the loader. My son was moving dirt, went to scoop up the last bucket and the arms would no longer lift, he said they had acted a bit weird "dropping slightly before lifting until it quit completely". Hydraulic level is full, all other cylinders, including the tilt cylinder on the loader bucket work fine. The outriggers and the backhoe cylinders all work as they should.

Thoughts? There have been some leaks around the control valves since we have owned the tractor. Does this sound more like a control valve issue or something in one or both of the cylinders?

wore out · Sep 27, 2023

Likely, a piston seal in one of the cylinders has failed.

If you have a helper hold the control lever in the lift position and LISTEN at each cylinder you MAY be able to hear some oil flow noise as the oil rushes past the failed seal and after the lever is held for a couple of minutes the leaking cylinder should be warmer than the other one. (Check by feel, or temperature 'gun'' if you have one.)

todintexas · Sep 27, 2023

Thank you for that info, I will have my son come out and we will give that test a try. I do have a temp gun, so we will try that also. Somewhat related question, the valve assembly, is it rebuildable? Even if it has not failed at this point it does leak, and I would like to stop that.

Janicholson · Sep 27, 2023

Woreout has a good method of determining the status of the cylinder piston seals. That loader should have down pressure as well as lift. if both of them have the same failure, no up no down, the piston seal is likely, not the valve. Valves usually have Oring seals to limit external leakage. they can be replaced. Take pictures at each step of disassembly. Label each hose and corresponding port with a color code, or number on clean surfaces both hose and port. Jim

todintexas · Sep 27, 2023

Correct, no up and no down, bucket just rests in the ground. "Tries" to move in either direction but nothing, all other cylinders work normally. We are about to go try the "listen and feel" method, lol.

(quoted from post at 19:36:26 09/27/23) Woreout has a good method of determining the status of the cylinder piston seals. That loader should have down pressure as well as lift. if both of them have the same failure, no up no down, the piston seal is likely, not the valve. Valves usually have Oring seals to limit external leakage. they can be replaced. Take pictures at each step of disassembly. Label each hose and corresponding port with a color code, or number on clean surfaces both hose and port. Jim

casecollectorsc · Sep 27, 2023

Piston seal failure. Just repaired my Case 70 loader because of it. Last of 50 bales and wouldn't lift. One seal had a third of the
seal blown out...first time since I bought the loader new in 72.

130ROY · Sep 28, 2023

Cap off the hoses to one lift cylinder at a time , you will see right away which one is bad .

todintexas · Sep 28, 2023

One side will still work and the other won't?

(quoted from post at 12:26:35 09/28/23) Cap off the hoses to one lift cylinder at a time , you will see right away which one is bad .

Loader Control Valves or Cylinder Failure?

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wore out

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Janicholson

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casecollectorsc

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