[mhahn]

Past couple times using the 6020 I have noticed that with a load in the bucket and the tractor running the loader will leak down very noticeably. But if I tilt the bucket a little or raise the loader a bit sometimes the leak down stops and the loader stays put. Also noticed that the leak down does happen every time the bucket has a load or not … like I said sometimes it does and other times it stays put. I read some older posts here about testing for valve or cylinder. Will follow those suggestions but wanted to ask the collective wisdom here if there is something else I should do given the intermittent behavior.

thanks … Mark

 

[Bob MacGregor]

Hi Mark,
Please be more specific for example, the bucket itself rotates downward dumping its load, but the loader arms remain in position.
The loader itself drops appearing that the cylinders(2) are collapsing.
Do you have any hydraulic oil leaks?
There are three areas to look at and diagnose:
The bucket cylinder itself and its related hoses.
The two loader lift cylinders and their related hoses.
The control valve that operates all three of these cylinders, the control valve itself and its related hoses.

https://www.casecoltingersoll.com/d3/manuals/ServiceManuals/Control%20Valve%20Manual%209-50382_watermarked.pdf

https://www.casecoltingersoll.com/d3/manuals/ServiceManuals/Hydraulic%20Cylinder%20Manual%209-99833_watermarked.pdf

https://www.casecoltingersoll.com/d3/manuals/ServiceManuals/Hydraulic%20Specifications%206018%20Loader%20Backhoe%20Manual%208-56630_watermarked.pdf

Notice in the cylinder manuals that the double directional cup seals are held onto the piston rod with a nut. This nut is known to come loose and fall off the rod and allow the cup seals to move away from their normal position. This is true with both loader lift cylinders, the bucket cylinder and the power steering cylinder, but not the 3point cylinder.
I have had to reseal the bucket cylinder on my 1998 6018L and the rod seal was leaking and the rod nut came loose. Fortunately these cylinders on 6000 and 7000 series tractors have a removable gland nut so these cylinders can be disassembled and resealed. However, the new cups need to be softened in very hot water in order to be able to install them into the cylinder. I assemble the rod with the new cups, O ring, spacers in the correct positions and install the nut with high tension/high temp Locktite sealant and allow to cure. Replace the seal, wiper seal in the gland nut with oil and install the gland nut O ring, install it onto the rod. With a pan with water on a hotplate, I heat the cups to soften them and carefully using oil, install the rod into the cylinder followed with the gland nut, tighten the gland nut. You can work the piston and rod back and forth with HP air to check it. As with anything hydraulic related, all parts must be cleaned and all must be oiled before reassembly.

 

[mhahn]

Hi Bob,

Thanks for detailed reply. Let me answer your questions. So far the only thing I have noticed is the loader leaking down. The bucket is holding firm and not moving.

I have not seen any evidence of leaks either from the loader lift cylinders or from the control valves.

Your theory that something internal to the lift cylinders is going on seems most plausible.

Does your theory also account for the intermittent nature of what I am observing? As I noted in my post, the loader at times appears to be visibly leaking down … meaning I can raise it, let go of the control lever and start to watch them leak down. Other times I raise the loader with a load in the bucket, let go of the control and the loader stays put. Crazy …

I guess I need to order some rebuild parts and tackle the lift cylinders …

Mark

 

[Bob MacGregor]

Hi Mark,
You may have noticed over time that many pics of 600, 6000 and 7000 series tractors show the panel under the steering tower missing. 644s and 646s do not have power steering but 648s, 6018s, 6020s and 7020s do, but they all have the bucket/loader control valve in common. This control valve linkages need to be lubricated with oil regularly. Removing this panel is required to lube this area, so it gets neglected until there is a problem and many times the panel gets misplaced. There are pins, links and a welded linkage that all wear. This area also gets dirty and usually not cleaned. I recommend that you remove the panel, clean and lube these linkages, test the hydraulics to see if this area is the cause of leakdown before you diagnose the cylinders.

https://www.casecoltingersoll.com/d3/manuals/PartsManuals/Ingersol%206018,%206018BH%20&%206018B%20Parts%20Manual%208-3051_watermarked.pdf

Check page 27.

 

[mhahn]

Thanks again Bob for your quick and thorough reply.

Stuck linkage in the control valve makes a great deal of sense especially given the intermittent nature of what I am experiencing. It is a simple fix to start by cleaning, inspecting and lubing all of those components. If that solves the problem it was an easy fix. If not well then at least we eliminated the easy stuff first.

I will try to tackle this coming weekend when I have some time. I will report back with my findings.

Again .. appreciate the time you took to provide the help and guidance.

Mark