John Deere 410 - Shes got issues!!!! Help!

[Tx Jim]

If you replaced frt pump without 1st performing proper diagnostics then you probably wasted money. Many hyd pumps have been replaced to determine that the pump replaced wasn't the problem. Turning hex socket screw in(CW) should under normal conditions increase pressure. Did you check sump screen for cleanliness? Did you check to be sure hyd filter relief valve wasn't stuck open? Do hyd's operate any different with hyd reverser in fwd or rev. Problem could be as simple as a leaking relief valve(key 24) or faulty o-ring(key 23).

 

[Nick410]

What is that diagram of? When I look at the exploded view I can't tell.

I've been through the sump screen, transmission relief and any check valve I can find.

Installing the new pump provided a huge amount of gain (all the hydraulics will operate now where as before I could only get the bucket to curl and an outrigger to move) however the issues is absolutely on the supply end.

There is no change in operation regardless of fwd reverse/ neutral.

There is some aeration In The oil and a milky color. I've been working on flushing the system but can only get so much at at a time.

My charge pressure is not reading on my 300psi gauge. My standby pressure is varying greatly. 500 at idle, about 1000psi at 1250rpm, 1500 psi at wide open throttle.

 

[jd110]

With the pressures you are seeing, I am guessing you have a large high pressure internal leak somewhere. Try starting it up and let it run for 10 minutes or so without using any functions. Then feel the pump and pressure lines from the pump to see if there is heat build up. When no functions are being used there should be no flow from the main pump and little to no heating of components. If pump and lines are warm or hot, follow the lines to the component that is hot. Steering valve is one fairly common area for internal leaks and heating of the oil. If you see no significant heat, then try capping off the main pressure line from the main pump and then recheck the standby pressure and charge pressure. The aeration of oil concerns me too, it could be a suction leak at the transmission pump or lines, but it also could be the main pump cavitating from the internal high pressure leak.

 

[Nick410]

I will check that tomorrow, thank you. I have felt the steering column, as another mechanic has mentioned the possibility of it leaking. I haven't felt any heat buildup there, but I will check again without using the hydraulics.

I have noticed the pump getting hot, but I was trying to work the hydraulics.

Also, the pressure drops roughly 500 psi when I use any of the backhoe control but not when I touch the loader controls.

I'm guessing an internal leak would require splitting from the transmission?

 

[Tx Jim]

What is that diagram of? When I look at the exploded view I can't tell.

I've been through the sump screen, transmission relief and any check valve I can find.
.

I can't remember exactly which control valve but I think it was either the loader boom or backhoe valve. Have you attempted to adjust stand-by pressure any higher?

 

[Nick410]

So today was the first cold morning we've had. Down to 15 overnight. I started her up and once she was running smooth worked the hydraulics. The loader actually worked. But as soon as the system heats up they slow and stop.

Seems like a leakin seal or somewhere that's not allowing the machine to build pressure. The thick oil is enough to actually build pressure and work the loader.

 

[Tx Jim]

My guess is internal hyd leak is causing trans pump to not be able to supply frt pump enough oil to keep front pump from cavitating(run low on oil) PS: frt pump doesn't have capability to suck oil. You're correct warmer to hot oil is more prone to cause cavitation than cold oil. I will suggest to remove backhoe hyd valve return hose(16) then aim hose in bucket or hyd filler hole then with all BH control levers in neutral start engine. No oil should exit open hose.