Hydraulic pump whine after valve installation?

[California]

... and the power shift is fine.

I don't think powershift could be involved since it has its own separate internal pump, driven by the transmission input shaft. I think the only way PS could be affected would be if the sump ran dry.

 

[Gypsyman]

Good to know on the Power-Shift.

I'm calling it a day as dinner's getting cold according to the wife.

Interesting development though. We have weather coming in tonight so I reconnected everything and topped off the trans. Fired her up and started cycling the cylinders to clear the air. For roughly the first 10 cycles everything was perfect. Smooth and quiet just like it should be.

Out of curiosity I kept cycling the cylinders and the problem crept back somewhere between the 10th and 15th cycle. Proceeded to clean up the shop for about 30 minutes and tried it again. The issue was still there but not nearly as bad.

I'm going to let it sit overnight and try it in the morning. If the fluid is aerated this should give it time to clear and possibly give me a direction to look for the cause.

Thanks for all of the input guys. I really appreciate it. More to come...

 

[oldnslo]

Whoops...

The noise and "hammering" start as soon as the control lever is moved. Even if you try to creep the control lever.

I'll have to pick up additional fitting tomorrow for inline pressure testing.

Richard

Your valve is the same exact valve I installed so there is a #4 SAE plug that can be removed and used as a pressure test port. I did notice on my valve there is more fluid flow noise when shifting the valves but no pulsing or shaking and excellant feathering capabilities.

Dumb question but... Does the joystick also pulse and jerk around at all or just the pressure lines? I believe these valves have the "load checks" in them that should not have any influence but they would be a variable that would not be the PBY circuit. You have stated the 3PH works fine is this empty or with a load on the arms?

If dead heading the flow and the system is smooth I would expect the 3PH to also be smooth under load but just trying to eliminate possible indicators of what could be happening.

 

[Gypsyman]

I've got the adapter for the test port coming. Should be here in the morning.

The stick and valve feel smooth with no feedback felt thru them. The hammering (for lack of a better term) can be seen in the soft lines and the actions of the cylinders. It's not violent but can be clearly seen. It can also be clearly felt in the stock hard line from the pump to the divider block.

The 3-point is loaded with 320 lbs of ballast and work smoothly. As I'm sure you already know the 186D's 3pt control valve is an "all or nothing" type of valve. It take very careful manipulation of the valve to creep the 3pt up. I tried something this morning. By moving the 3pt lever in very tiny increments you can get the 3pt to lift slowly. If I do this I can get the 3pt's action to cause the noise. If you just pull the lever (which provides full flow) and let it kick out automatically at the top of the travel, no noise.

 

[oldnslo]

When you installed the LVT valve is the return/tank line new or was this an existing return line you connected too?
Reason for asking is that if new:

Does this line return below oil level? Yes = good, If No, this will aerate the oil when the LVT is used or oil is forced over the relief valve.

Does this line direct the return flow towards the pump inlet line? If yes this can also aerate the oil or force/direct aerated oil towards the pump inlet.

Both of the above scenarios would help explain why it ran for awhile last night and then progressively got worse

Interesting that the 3PH also causes the same symptoms. Be curious to see what the gauge shows.

best of luck

 

[Gypsyman]

The relief return to tank was connected with a new line to the Yanmar specified port on the side of the transmission. I was concerned as it appears to be above the level of the trans oil. Unfortunately the manual doesn't show if it's just an open port that dumps freely back to the sump or if it's a port that is routed down below oil fill level.

The 3pt only seems to cause the problem to a small degree and only when the 3pt control valve is really feathered.

I'll run some tests and post the results.

Richard

 

[Gypsyman]

It appears that I've found a solution but it doesn't explain the problem. I'll get to that in a minute...

Hydraulic test results:

3pt shows between 800 and 1000 psi when lifting the 320 lbs of ballast that I have loaded.

Chute rotation show 400-500 psi.

Blower lift shows about 800 psi. It's a short cylinder so things happen fast and it's hard to catch on the gauge.

When the noise occurs it shows about a 100 psi drop on the gauge. Again, it happens so fast that it's hard to get super accurate numbers.

All psi numbers appear normal per the manual.

Here's the kicker and what appears to be the solution. Since I've owned the tractor I've noticed that the hydraulic sounds while running in neutral always seem different when the clutch is let out and the transmissions internal pump is spinning. The 336D that I just sold was the same way. To date I've done all of the testing on the 186D with the clutch disengaged via the safety catch.

This morning I decided to let the clutch out during testing. I must have cycled the chute cylinder 50 times without any noise at all. Without shutting the tractor off I depressed the clutch and set the safety catch to keep it depressed. After about 10 cycles of the chute cylinder the noise was returning. Without shutting the engine down I once again let the clutch out and let the tractor run for about 30 seconds before I started cycling the cylinder again. No noise at all after 30 or so full travel passes.

I've studied the flow routing diagrams in the manual and I don't see how the transmission pump being engaged could effect the hydraulic pumps performance but it sure appears to. The only commonality I can find between the two is that they are both fed by the same factory strainer.

Richard

 

[winston1]

Sounds like the power shift pump is moving enough fluid to starve the main hydraulic pump. You have cleaned the strainer twice so that shouldn't be the problem. Any possibility there could be an obstruction in your suction line going to the main pump? Collapsed hose? Loose clamp allowing pump to suck in air? Just throwing things out there.

 

[Car Doc]

Here is my thinking....add a few quarts too much oil and try that. Just throwing that out you can always drain some with a siphon later.

My other thought is why have the clutch in anyway? It will be out when working any way or most of the time guess I dont see why it would matter either way just seems strange to me to have the clutch in I guess.

 

[Gypsyman]

Sounds like the power shift pump is moving enough fluid to starve the main hydraulic pump. You have cleaned the strainer twice so that shouldn't be the problem. Any possibility there could be an obstruction in your suction line going to the main pump? Collapsed hose? Loose clamp allowing pump to suck in air? Just throwing things out there.

That's what I thought but it appears to be the direct opposite. The system is quiet when the powershift pump is running. Push the clutch in (powershift pump not engaged) and the hydraulic noise returns.

I dumped the entire system last night. Checked the strainer for a 3rd time and pulled the rubber section of the suction line. I blew back into the hard portion of the suction line and it appears clear as does the rubber section.

Here is something else that I've noticed about the design of the hydraulic circuit.

The suction strainer is above the tank fluid level. When you pull the cover to remove the strainer the chamber that it sits in is not full of fluid. This means that everytime you shut the tractor down that chamber drains back to the sump and fills with air. This also means that everytime you start the tractor that chamber must be refilled and the resulting air passed thru the system before the entire system is charged again.

It seems like a strange design to me. I would have expected there to be a check ball of some sort in the suction port from the sump. It would be a mess when you went to pull the strainer but at least you wouldn't be sucking a big pocket of air into the system at every startup.

I'm going to try an overfill tonight and repeat the test. It shouldn't need to be overfilled but surely can't hurt.