L 35 hydraulic load at idle

[Jay E]

Hello, new to this forum. Have an L35, use it for work around the ranch. Recently did a complete fluid change everything worked ok. Around 15 hours later the idle was suddenly very low, there is now a constant hydraulic load on the engine. I need to use the throttle lever advanced just to idle. The power is low on every hydraulic function. I thought it might be the three point, so I unhooked the return hose and added a fitting so it would pump straight back into the fill, but it didnt make any difference. If I have the line unhooked, it slows down much more. Plenty of flow out the line. Oddly enough it seems that the three point/backhoe position l\ever doesnt seem to matter whether it is pulled or in. If I recall it seemed that it used to have a load if I forgot to change that, could this be the problem? I only add this, because even if I had it correctly positioned, if I moved the three point to the up position too far, it would do the same load stall. Replaced suction filter. No help. Thanks

 

[mickeyd]

Welcome Jay to the OTT forum. There are some very knowledgeable people here who can really help.

They should be along shortly. Good Luck.

 

[L35]

Hello, new to this forum. Have an L35, use it for work around the ranch. Recently did a complete fluid change everything worked ok. Around 15 hours later the idle was suddenly very low, there is now a constant hydraulic load on the engine. I need to use the throttle lever advanced just to idle. The power is low on every hydraulic function. I thought it might be the three point, so I unhooked the return hose and added a fitting so it would pump straight back into the fill, but it didnt make any difference. If I have the line unhooked, it slows down much more. Plenty of flow out the line. Oddly enough it seems that the three point/backhoe position l\ever doesnt seem to matter whether it is pulled or in. If I recall it seemed that it used to have a load if I forgot to change that, could this be the problem? I only add this, because even if I had it correctly positioned, if I moved the three point to the up position too far, it would do the same load stall. Replaced suction filter. No help. Thanks

couple of points, the line out back that goes to the backhoe plugs right back into itself when the backhoe is off the machine. With mine, if it’s not connected it will make some horrible noises and run the idle way down. As far as the 3pt lever, if I recall mine is the same, I don’t notice much difference weather it’s in or out. Did you use an oem or similar quality filter? It’s possible it could collapse on itself restricting flow. I’m sure there’s more things to test but they are past my pay grade!

 

[Jay E]

couple of points, the line out back that goes to the backhoe plugs right back into itself when the backhoe is off the machine. Did you use an oem or similar quality filter? It***8217;s possible it could collapse on itself restricting flow. I***8217;m sure there***8217;s more things to test but they are past my pay grade!

It is plugged in. As a reference it it drops around 250 RPM at an idle with it unplugged and this is about the same amount it is idling low from normal. So that is what makes me think it is hydraulic. All the filters are OEM. Also since it is a suction filter system I dont think a clog would cause it to load, rather I think it would just suck air or cavitate.

It has the load at all times, I just notice it most at idle because the engine almost stalls if I dont use the hand throttle to raise it. The rest of the time it just takes power away from all the other functions.

I've worked on John Deere Hydraulics quite a bit, but that is a closed system and functions differently. I do have a flowmeter if someone here could suggest places to hook it up and the flow/pressure chart.

Thanks

 

[rbargeron]

......it seems that the three point/backhoe position l\ever doesnt seem to matter whether it is pulled or in. If I recall it seemed that it used to have a load if I forgot to change that, could this be the problem? I only add this, because even if I had it correctly positioned, if I moved the three point to the up position too far, it would do the same load stall.....

It sounds like the 3-point position feedback may be out of adjustment. On my rigs raising the lever beyond the high stop definitely loads the system. Or maybe something is blocking flow in the selector valve. There's some related reading here. Good luck, Dick B

 

[Jay E]

It sounds like the 3-point position feedback may be out of adjustment. On my rigs raising the lever beyond the high stop definitely loads the system. Or maybe something is blocking flow in the selector valve. There's some related reading here. Good luck, Dick B

Thanks for the post. I read the post and think he is talking about the backhoe/threepoint lever. Mine moves just fine, although nothing different happens when it is moved to either position. What is supposed to happen? Could this be an indicator of a problem. It is a booger to get to, a lot of sheet metal to remove. To check it I removed and bypassed the fluid in hose, which removes the selector valve completely from the system and it didn't pick up any RPM. SO I dont think it is the selector valve. I had to weld a stop on slot of the three point high stop or it was loading the system, just like yours. As a reference, it acts like loaded like that (raising the lever too far on the high stop) all the time, regardless of where it is positioned. The three point goes up and down normally.

Hope someone else has input. I wouldn't care except the backhoe and front loaderis now a dog as some percentage of the Hydro power is being taken up as load somewhere else.

 

[rbargeron]

...... the backhoe/threepoint lever. Mine moves just fine, although nothing different happens when it is moved to either position. What is supposed to happen?.......

It's a selector that either powers the backhoe or the three-point, but not both at the same time. I dunno what symptoms would arise if left midway. Maybe the valve isn't moving full stroke or seals inside are leaking between ports? If its powering the 3 point all the time and the feedback rod is bent or broken it will keep hunting, sapping power. Sorry I'm not more help.

Do the power steering and GST act normally?

 

[Jay E]

If its powering the 3 point all the time and the feedback rod is bent or broken it will keep hunting, sapping power.
Do the power steering and GST act normally?

Thanks for replying. The entire system was bypassed and it made no difference, so it is not that. Yes the power steering is normal. I donty know what GST is.

I'm going to put a flowmeter inline right after the hydraulic outlet and see what the running pressure (and flow) is. Hopefully it will be low, but if not I'll start measuring downstream until I find the restriction.
Anyone know what the pump should be putting out at what pressure?

 

[Indiapaleale]

Hi Jay E I know it’s a long shot but did you try reseating all the quick connects especially the power beyond port for the backhoe attachment

 

[rbargeron]

......Anyone know what the pump should be putting out at what pressure?

Being an open center system the outlet pressure at the pump should be minimal, maybe only a few psi at high idle (oil warmed up).

 

[Jay E]

Being an open center system the outlet pressure at the pump should be minimal, maybe only a few psi at high idle (oil warmed up).

Rather than get into a bunch of fitting and gauges, I just unhooked the hydraulic fluid at the pump outlet and ran a hose right back to the tank. Unfortunately it simply showed there was no hydraulic back pressure and yet the engine was still dragged down somewhere. So the drag on the engine is somewhere else (unless it is the steering pump I'll try that one next).

Anyone got any other ideas? Where else could there be drag? Putting the F/R in neutral and the gear in neutral didnt change the drag.

 

[rbargeron]

The L35's glide shift transmission has several internal valves. The system gets its hydraulic power from the steering pump circuit. I'm wondering if one of its valves or regulators could be causing the persistent load. Diagnosis involves pressure readings at a few points (WSM walks through the process). Maybe Wolfman will have some ideas....

 

[Jay E]

T Diagnosis involves pressure readings at a few points (WSM walks through the process). Maybe Wolfman will have some ideas....

That would make sense, although it doesnt creep or anything. IS the pump internal or is there a hose I can diosconnect to remove all the systems at the pump?

What is WSM, some kind of service manual?

 

[Newlyme]

WSM=Work Shop Manual.