Ford 6610 - weak loader hydraulics

[nfrost]

Background: last summer I purchased a 6610 with loader. The loader controls and valve were so poorly rigged, I replaced both with an appropriately rated new CCLS valve and joystick combo. The plumbing is correct in that it's supplied from a TEE in the large pressure line connecting the priority valve to the rear remotes. The return is plumbed back to the hydraulic system filler neck. The load sense line comes from a shuttle valve TEE.

I discovered that i only had about 1800psi at the remotes, so I followed instructions i found to remove the priority valve, inspect the mesh screen, remove the relief valve set screw, (scribing and counting turns so it would go back to the same position), and cleaning the trash from the ball and seat area. After doing this, I restored the 2500psi of pressure at my rear remotes.

Additionaly, I removed the load sense line from the priority valve and verified that i have pressure coming from the remotes when I engage a remote lever.

Bearing in mind that I've never operated this tractor with "good" controls or pressure, I'm not sure how well this loader should perform.

My issue is this: overall, the loader seems weak to me. It'll lift a round bale of hay, etc just fine but not the rear end of a 3/4 ton pickup or a decent sized tree that's been cut.

Here's the kicker. While fiddling around to troubleshoot this issue and learn more about this tractor, I have found that if I engage (and hold) one of the rear remotes at the same time i operate the loader, it'll respond much more like i expect. It'll lift the rear of that pickup and cut tree effortlessly. I'm not sure if these results are the "normal" operation or if I'm overloading the system.

This tractor has both hydraulic pumps and my gut is telling me that somethings not right inside the prioroty/sequencing valve and when I send pressure to the remote and loader at the same time, I'm overcoming whatever it is thats "not right" and seeing normal operation.

I'm not sure if there are some settings that need to be adjusted, maybe that relieve valve setscrew is too tight/loose, or another source of failure that would result in this condition.

I know @RodinNS, @Harry in Ky, @TractorTech, and @bern are extremely knowledgeable in this area and hope they chime in with their thoughts. I think it was Rod's detailed instructions I followed to disassemble and clean the relief valve.

I appreciate any and all thoughts/suggestions.

 

[Harry in Ky]

Here's my first thought. Using the loader by itself seems to be lacking in performance. Stroking a remote lever makes the system perform better. That tells me you have a problem with the sensing circuit from the loader valve. Either the valve is not sending the sensing signal, or a shuttle tee connection somewhere isn't doing it's job. The combining valve isn't getting the signal until one of the remote valves is operated and that sensing signal is triggering the combining valve.

 

[Cycledude]

Have you tried eliminating the joystick ?
What condition are the hoses ?
Put new hoses on my 6610 and that was a major improvement.

 

[nfrost]

@Cycledude @Harry in Ky -

Thank you both. Your inputs got me to thinking......

When I installed the new loader valve I did check the pressure coming from the sense port (of the new valve) and felt like it was adequate, although I never found a spec and I don't remember the pressure I saw. I also pulled the shuttle TEE and verified it was free and checked both ways, although I don't recall the specific ports which opened and closed. I clearly didn't do a very good job of making notes and this has been several months ago.

The sense line from the loader valve is a combination of 1/8" npt nipple, elbow, and small hydraulic hose. The factory sense tubing on the tractor is small so I think the 1/8" pipe and hose is adequate. It would make sense that if the hose was degraded, it could affect the signal and cause my issue - especially if it needs to see a minimum flow and not just pressure.

I think my next step is to disconnect the sense line from the priority pack and compare 3 seperate pressure readings from: loader valve, remotes, and combined. I'd expect the combined reading would be the same as the remote reading as the shuttle TEE should only let the highest pressure side pass through and block the lower side.

I'll also pull the shuttle TEE, re-inspect, and confirm it closes the remote port when the loader valve is actuated and vice versa. I'll do this in the next day or 2 and report my findings.

Does the priority pack need to see a minimum flow (volume) or just pressure?

Anything else you'd check at this point?

Thanks

 

[oldnslo]

My experience is that a load sense line should be a minimum of 3/8” line unless it is a very short line of a couple feet or less. Depending on control style could be very little flow or 1/2 to 3/4 GPM. Some have a bleed orifice at the pump and some don’t. You are dealing with low pressure differential between LS setting and main pressure so any loss is noticeable.

 

[Harry in Ky]

Before changing any other parts I think I would disconnect the sensing lines at the priority valve. Separate the lines, and only hook up the one from the loader valve, leaving the line from the remotes out of the equation. I've seen too many shuttle checks give false signals causing similar problems (either no signal at all or signal not cancelling out). See if your existing line will trigger the combining valve properly if it's the only thing hooked up. If not, then revisit the circuit, and/or lines involved.

 

[Cycledude]

I really didn’t like the joystick because it was mounted to far forward and even though it was adjustable it just wasn’t comfortable when backing up and looking over my shoulder.
So I removed the joystick and just used the two levers beside the seat.
Only the last couple feet of hose looked bad where they plugged into the couplers and I was worried they might blow out someday so I replaced them. I was quite surprised at how much everything speeded up after replacing those hoses, there must have been something wrong inside the hoses.
A year or 2 later I sold the loader simply because after buying my LS XR4155 with hydrostatic drive I pretty much quit using it.

 

[oldnslo]

Nfrost
A couple of things to check along with suggestions from Harry are:

Is the LS shuttle going to the rear remotes leaking a little causing the LS signal from loader valve to be little lower. This would become evident if system works with the rear remote LS signal line removed.

Operate just loader raise does system build correct pressure with rear remote LS line removed?
If yes suspect bleeding back through LS shuttle to rear remote.
If no try curl only. Do you get correct pressure? If yes could have a LS check leaking in loader valve or you might not be getting enough LS flow from the new loader valve. A test for this is operate both bucket raise and curl at the same time. If works now that would also indicate not getting enough flow from new loader valve.

I have had a couple of problems in the past with valves not supplying enough flow and LS checks getting a piece of crud in them.

Hope the above makes sense.

 

[nfrost]

Gents,

Apologies for the delayed response. I was able to get back on this last night and using your suggestions, have learned more:

- With the shuttle TEE disconnect from the remotes, it did leak when operating the loader. I removed it and thoroughly cleaned the check ball area. No visible trash or damage found with the ball or seats. (I realize it doesn't take much to prevent it from fully seating and sealing).

- The load sense line is 6' long made up of 1/4" hose and 1/8" npt fittings. Based on your input, I've ordered parts to upgrade this to 3/8 hose and JIC fittings. The old hose was old and rough, so I'm hoping the condition plus the length is my primary issue here. (I'm wondering if line resistance/undersizing is causing the shuttle to not slam against the seat and not seal properly).

- When lifting only, I measured 120psi load sense output from the new loader valve port (without load sense line) which is just 5psi lower than what I measured from just the remotes when deadheading, so this seems like it should be fine (in the absence of actual pressure specs).

- When lifting and deadheading the remotes, i received inconsistent reading on the load sense line when disconnected from the combining valve. I'm not sure what this means, so I'll upgrade the hose size, retest, and go from there.

- When lifting AND curling, the load sense pressure from the loader valve was considerably higher (pegged my 200psi gauge) so i guess that makes sense and would appear to be normal since there's more of a hydraulic load/demand.

Oldnslo: Your question...... "Operate just loader raise does system build correct pressure with rear remote LS line removed?".......I'm not sure what the correct pressure should be. Should I have 2500psi going to my lift cylinders?

Once I get the parts in and new 3/8" hose/fittings installed, I'll test and report back.

Appreciate all your input.

 

[oldnslo]

Nfrost
Yes you should have same or similar max pressure when operating each function independently. I.e. lift should be 2500 PSI, curl should be 2500 PSI, etc. Running multiple functions should provide similar pressure also.

I think you realize this but you will only see pressure required to move the load so if loader or bucket is moving pressure will most likely be less than 2500.