M6800 slow lift

[Napi]

I've got a M6800 with hydraulic shuttle that I bought new. The 3 point lift is very slow. I've had it checked by 2 different dealers. They say it's the nature of the beast. I know a guy that has a 6800 and his works alot faster than mine. It's to the point that when getting to the end of the row, you have to stop and wait for the lift to come up before turning around. And the knob under the seat doesn't help any. The valve on the right hand side of the transmission for a loader is in the correct position.

My old 1957 JD 620 was twice as fast coming up.

 

[art]

You do have a problem. It's to bad that the dealers didn't take the time to pressure test it and only looked at it.

 

[GATC35]

Do you have draft control? If so make sure it is in the proper configutation. Also remove, clean and lubricate all pins, bushings, springs etc where the top link attaches associated with the draft control. Yes, actually take them apart.

 

[Napi]

OK, I'll try that. One dealer did change the hydraulic filters on the side, but no change. I'm thinking it's a fluid flow problem because it picks up weight fine, just slow as pond water!

 

[nostep]

If it picks up weight, then it has plenty of pressure. The problem is then most likely a restriction in the valve, hoses or lift cylinder (could also be adjustment valve is stuck internally). I have made flow restrictors out pipe plugs with 1/8" holes drilled in them. Slows down the device considerably, but the final ability to produce force is still fully there (i.e., you have a flow problem). You'll need to find the hydraulic schematics and/or the parts breakdown manual and tear it apart.

 

[kthompson]

I have a M6800 and the lift is not slow. I do keep my valve under the seat fully open. Are you sure you have correct hyd fluid in it? As have been said, check the set up of the draft control. It is covered in the manual. But, at what rpm's are you running this? If you are running just above an idle mine is much slower than at say 1500 rpms, big difference. Could that be the problem?

 

[Napi]

Yeah, I still think it's a flow problem. Sad part is the tractor is an '05 and just turned 78 hours yesterday. I'm just now starting to use it a good bit. The fluid is factory except what they lost when they changed the filters. The valve under the seat is wide open, but it only controls the rate of drop. Draft control has been tried from deep to all the way up. Correct me if I'm wrong, but the draft is to keep an implement somewhat at a steady level when encountering uneven ground.

The valve for loader usage on the side of the transmission is in the correct position according to the manual. The tractor had a loader from the factory. I didn't want a loader because I have a backhoe/loader. What does that valve do exactly? Do you think it could be stuck?

 

[nostep]

Bear with me . . .

Hydraulic circuit is like a pond with a pump and a garden hose. When the pump is flowing, the water goes through the hose and you let it run back into the pond if you don't need water. When you need pressure, you divert the water from the hose and through a device like a sprinkler, but the water still ends up in the pond. If you have more than one device, you select each device one at a time, but you cannot totally stop the flow.

Pond = Reservoir

Pump = Pump

Hose = hose

Sprinkler = lift, loader, etc.

The loader or attachment valve you mention previously is used to divert the hydraulics flow through the external valves or to just leave the flow inside the tractor (so it can get back to the reservoir). I would say you don't have a problem there because you can still lift the load. If the flow was flowing freely back to tank (and not through your lift) then you would have no pressure.

I still say that you most likely have a clog somewhere or a messed up control valve . . .

 

[Napi]

I agree. Now if we could just get the dealer to understand. I called the service manager yesterday where I had it last and she hasn't got back with me yet, maybe today. I think Kubota should do something since the issue was never resolved while under warranty.

I noticed the 7040 which my tractor evolved into has lift cylinders on the outside. My 6800 has an internal lift.

Thanks for the help.