YM2002D hydraulic cavitation - Air Leak? Control Valve part?

[scooter133]

YM2002D After about 15-30 Minutes of using the hydraulics (Bucket or 3Pt) the controls get sluggish and or cavitate.

Replaced the Hydraulic Oil
Replaced the Hydraulic Oil Filter
Cleaned the Oil Suction Screen
Replaced Hydraulic ram O-Ring and white washer thing
Replaces all the O-Rings when replacing the Control valve face.
Replaced Hose to Hydraulic Oil Filter housing
Replaced Hose to Hydraulic Pump from Hydraulic Oil Filter housing
Replaced the Hydraulic Pump
Removed the Bucket Control Joystick Valve box.
Pump output dumped into 3Pt Valve Control box
(Eliminating any of the Bucket Valve and hydraulic lines)

3Pt Mower attached, started cavitating when lifting at 30ish minutes into the mow.

cavitation with Bucket: acted jittery, Up and Back were jerky at best. then it was like we lost all hydraulic pressure.

cavitation with 3PT-Mower only: lifting became jittery, like it was lagging behind the controls. responded erratic.

I thought there Might have been a Leak on the Filter Screen cap. (The 3 Point Circle cap with the 10m screws)
Though upon further inspection the leak is coming from where the left Rear Axel Gear box bolts to the main engine body, just above the filter screen cap. Actually a few places at that joint.

The pictures show some shiny spots in the cracks between the two chassis pieces. they apparently leak much more than I thought. like a lot more.

Question: being so close to the intake, could after the tractor and the hydraulic fluid heating up, cause air to be sucked in to cause the cavitation?

Question: Could this be one of the spring, o-ring contraptions that control the pressure? The Numbered Items below.

Yellow parts re where I see the oil seeping from.

 

[winston1]

Your main relief valve is the one on the top right of your picture. It would be set about 2123-2275 psi with engine at 1500 rpm and warm fluid.

Your safety relief valve is the one one the bottom left. It's function is to relieve such as when your going down the road with a heavy implement and hit a pot hole. Your implement bounces and causes high pressure. It should be set at 2417 to 2702 psi. These numbers are out of a 220/226 manual. I am confident it is the same system you have . I owned a 2002D for several years.

You are sucking air into the suction somewhere.

 

[careyo63]

Pinch or debris clogging the Hyd. line. Old with a pin hole crack in it?. Happened on my FEL.. line just before the Hyd. pump itself. Swelled up inside the line where it had a sharp bend in it. Pretty much pinched it off inside. Same thing. New Fluid ,Filter Etc.. I just did all the Maint. on it. I was lucky and looked inside the Hyd. line itself. Big swelled up Bubbled up inside it.

 

[scooter133]

Pinch or debris clogging the Hyd. line. Old with a pin hole crack in it?. Happened on my FEL.. line just before the Hyd. pump itself. Swelled up inside the line where it had a sharp bend in it. Pretty much pinched it off inside. Same thing. New Fluid ,Filter Etc.. I just did all the Maint. on it. I was lucky and looked inside the Hyd. line itself. Big swelled up Bubbled up inside it.

 

[scooter133]

@careyo63 I Edited the post, but I did replace the rubber hose to the filter housing from the suction line. I also replaced the rubber hose from the filter housing to the Pump.

There is one small rubber hose section I can replace under neath on the suction line.


Is it possible that the Air is coming in the place that its leaking on the chassis case?

 

[careyo63]

Next place to be looking. The piece of hose I was referring to was 6" if that. It wasn't very long.

 

[scooter133]

Next place to be looking. The piece of hose I was referring to was 6" if that. It wasn't very long.

You talking about the hose at the left of the Blue highlighted line? I have yet to replace that. The other hoses looked fine, so I was thinking of cutting one of the ones with the 90º bend to fit the strait section.

The Green Highlighted transmission shaft. Does that also carry the Hydraulic fluid to the front Axel/Steering? Those clamps around the rubber parts are not 100%.

 

[careyo63]

Very nice! Look at the o-ring on the pump itself. Both for that matter. Suction and pressure lines. Not 100% sure how it connects but the YmY2500 did have one and it did start to leak.

 

[AaronM]

You talking about the hose at the left of the Blue highlighted line? I have yet to replace that. The other hoses looked fine, so I was thinking of cutting one of the ones with the 90º bend to fit the strait section.

The Green Highlighted transmission shaft. Does that also carry the Hydraulic fluid to the front Axel/Steering? Those clamps around the rubber parts are not 100%.

View attachment 4080409

We have seen several times where that blue section of hose on the left was cracked (dry rot) or loose and would suck air. Many times it would not even show a visible oil leak.

Aaron