Non-functioning hydraulics

[Dashman]

I have a Kubota L4300DT with an LB552 FEL controlled by a HUSCO 9210 control valve. A few years ago, I installed remote hydraulic lines and a controller. Last year, I had fluid leaks at the quick disconnects and I needed to replace the lift spool float detent mechanism. I also had a transmission shift stick boot deteriorate and got some water into the fluid. I rebuilt the control valve, drained the hydraulic fluid from (4) places, installed the control valve, replaced the filter, filled with fluid, and I started the tractor to flush some fluid from the PB circuit prior to the remote valve. I've kept the fluid level in the sight plug.

When I re-installed the PB hose to the remote controller and re-started the tractor, I didn't have hydraulic pressure to the FEL nor the 3 point hitch.

I tried pushing air into the rear fill hole, and pushing oil into the outlet/inlet hose to the FEL control valve. On the hydraulic block left to right the ports are: inlet, outlet, and tank. That hose from the outlet port on the block goes to the inlet of the FEL control valve. Correct?

I cracked the PB hose just to see if fluid would leak, and sure enough it did. I cracked the filter, and sure enough fluid leaked there too. I don't hear any whine from the pump, and the steering works fine. I can't move the tractor because the FEL is down. What am I missing? Thank you.

 

[Russell King]

The FEL is normally first in line so the flow is this:
Tractor pump out to FEL valve inlet then out the Power Beyond (PB) of the FEL into the rear remote power in port. Then out of that valve PB port and to the 3PH valve. That last connection is often a hose back to the tractor near where the hydraulics flow came out.

From the operating manual for your tractor on page 37 there is also a manual selector that must be in the correct position. That is most likely the problem.

 

[Dashman]

Thank you for your response Russell!

I have both the tractor and loader manuals. I followed the loader manual extensively when I added the remote control valve. Today I rotated the "control screw" horizontal and back to vertical while the tractor was on with no change.

Tomorrow I'm going to go one step further, and remove the outlet hose from the remote control valve to make sure I'm getting flow through that control valve to the hydraulic block.

 

[North Idaho Wolfman]

I have a Kubota L4300DT with an LB552 FEL controlled by a HUSCO 9210 control valve. A few years ago, I installed remote hydraulic lines and a controller. Last year, I had fluid leaks at the quick disconnects and I needed to replace the lift spool float detent mechanism. I also had a transmission shift stick boot deteriorate and got some water into the fluid. I rebuilt the control valve, drained the hydraulic fluid from (4) places, installed the control valve, replaced the filter, filled with fluid, and I started the tractor to flush some fluid from the PB circuit prior to the remote valve. I've kept the fluid level in the sight plug.

When I re-installed the PB hose to the remote controller and re-started the tractor, I didn't have hydraulic pressure to the FEL nor the 3 point hitch.

I tried pushing air into the rear fill hole, and pushing oil into the outlet/inlet hose to the FEL control valve. On the hydraulic block left to right the ports are: inlet, outlet, and tank. That hose from the outlet port on the block goes to the inlet of the FEL control valve. Correct?

I cracked the PB hose just to see if fluid would leak, and sure enough it did. I cracked the filter, and sure enough fluid leaked there too. I don't hear any whine from the pump, and the steering works fine. I can't move the tractor because the FEL is down. What am I missing? Thank you.

It sounds like you have swapped the PB and tank lines.

 

[Dashman]

I thought that might be a possibility, so I checked the Prince MB single spool port descriptions. I have the PB from the FEL control valve into the inlet of the remote valve. The outlet is on the opposite side of the valve, and that is routed to a tee to the tank port on the hydraulic block. The PB of the remote valve is just above that, and is routed to the inlet port of the hydraulic block. I sketched it out, and seems correct. Let me know, if I'm not.

Come to think of it, I had that inlet port fitting cracked to loosen one of the other hoses, and I didn't notice much fluid leaking from it. I'm going to fully remove it tomorrow and start the tractor. If fluid doesn't come out, I'm going to think that some water in the fluid that didn't drain has frozen in the remote valve.

If the remote valve is blocking flow to the 3 point hitch valve, then why doesn't the FEL work?

 

[North Idaho Wolfman]

I thought that might be a possibility, so I checked the Prince MB single spool port descriptions. I have the PB from the FEL control valve into the inlet of the remote valve. The outlet is on the opposite side of the valve, and that is routed to a tee to the tank port on the hydraulic block. The PB of the remote valve is just above that, and is routed to the inlet port of the hydraulic block. I sketched it out, and seems correct. Let me know, if I'm not.

Come to think of it, I had that inlet port fitting cracked to loosen one of the other hoses, and I didn't notice much fluid leaking from it. I'm going to fully remove it tomorrow and start the tractor. If fluid doesn't come out, I'm going to think that some water in the fluid that didn't drain has frozen in the remote valve.

If the remote valve is blocking flow to the 3 point hitch valve, then why doesn't the FEL work?

More likely water frozen in the filter or the suction side, than in a valve.

 

[Russell King]

Come to think of it, I had that inlet port fitting cracked to loosen one of the other hoses, and I didn't notice much fluid leaking from it. I'm going to fully remove it tomorrow and start the tractor. If fluid doesn't come out, I'm going to think that some water in the fluid that didn't drain has frozen in the remote valve.

But isn’t it above freezing now (and for a few days now)?

 

[Dashman]

Hello Russell and Wolfman,

Yes, it's been mid-60s for a few days here, but it does freeze at night.

I removed the PB hose to the inlet port on the hydraulic block, and there was flow with the tractor on. It wasn't a stream though. I caught about a quart in a few seconds. It wasn't milky, but it did have some micro bubbles.

Isn't there a regulator mounted on top of the pump on my L4300? Could I have affected something with the regulator that reduced the pressure?

 

[North Idaho Wolfman]

Hello Russell and Wolfman,

Yes, it's been mid-60s for a few days here, but it does freeze at night.

I removed the PB hose to the inlet port on the hydraulic block, and there was flow with the tractor on. It wasn't a stream though. I caught about a quart in a few seconds. It wasn't milky, but it did have some micro bubbles.

Isn't there a regulator mounted on top of the pump on my L4300? Could I have affected something with the regulator that reduced the pressure?

The output for the loader and three point section of the pump has no regulator only the PS section.
Loosen the output line at the block, and see what you get there.

 

[Dashman]

Today my 2nd new filter arrived, so I removed the 1st new filter and installed the 2nd. The oil that drained had some air bubbles and foam, not a lot but a little bit. I refilled about 2 quarts of the Shell Spirax S4 TXM hydraulic oil that I've been using. It's what was in it since 4 years ago. Still no functioning hydraulics.

I cracked the rear banjo bolt to the 3 point hydraulics about 1 turn, and it leaked. Then I started the tractor and it sprayed a bit. I shut it down in a couple of seconds. I cleaned around the area, tightened the banjo bolt, and restarted. Still no hydraulics.

I can't see any leaks and there's no abnormal sounds coming from the hydraulic pump. Is it time to check the outlet pressure? Would I put a line with a gauge on port "B" from the block?

 

[Russell King]

I don’t think you need to worry about pressure right now but if you want to you can. I believe you can get a gauge (with the proper range) and use one of the loader cylinder hoses and just put the gauge (on a disconnect half) and attach the gauge to the line and operate the valve to move that cylinder. Your loader valve MUST have a pressure relief valve in it to do the test in this way.

I would start your testing by removing the power in hose from the FEL valve so it is still connected to the tractor. Put the end into a clean 5 gallon bucket (so you can put the oil back into the tractor). Start your tractor and see if oil is pumped into the bucket. Don’t run it to long though or it will pump the sump dry of oil. Depending on how much oil is in the bucket, then put it back in the sump or wait until the second test is complete.

If you get oil then put the hose back, and move to the next valve and repeat the process (the PB line out of FEL valve should be the Pin of the next valve. Go to next Valve if you get flow.

Post the results.

If no flow in first test then you will need to figure out what is wrong with the pump.

 

[Dashman]

I had already removed the PB hoses, but I did it again anyway. There was flow from both the FEL and remote control valves. After just a few seconds it amounted to about 1 quart. It was not a lot of flow, and not any substantial pressure.

So, I removed the relief valve, and added (3) #10 washers. That didn't make a difference. I don't see a reason to hook up a pressure gauge when it's obvious that the pressure is off by a magnitude of at least 100 (20 psi vs. 2,000 psi).

I'm guessing that the water in the system wore out the pump gradually with time. The only thing I can think is that the pump began to prefer the thicker water mixed fluid, which is why everything was operating before I did the fluid change. The steering still works because it still has the contaminated fluid.

I'll be replacing the pump, and I'll report back then.

 

[TheOldHokie]

I had already removed the PB hoses, but I did it again anyway. There was flow from both the FEL and remote control valves. After just a few seconds it amounted to about 1 quart. It was not a lot of flow, and not any substantial pressure.

So, I removed the relief valve, and added (3) #10 washers. That didn't make a difference. I don't see a reason to hook up a pressure gauge when it's obvious that the pressure is off by a magnitude of at least 100 (20 psi vs. 2,000 psi).

I'm guessing that the water in the system wore out the pump gradually with time. The only thing I can think is that the pump began to prefer the thicker water mixed fluid, which is why everything .I ni n fluid change. The steering inmn m because it still has the contaminated ing.
G


be replacing the pump, and I'll report back then.

A quart in a few seconds is substantial.
I would measure pressure at the main relief valve before condemning the pump. E.g. the loader relief could be bad

Dan

 

[Russell King]

@Dashman
There won’t really be much pressure out of the pump until there is a resistance against the flow so don’t expect to see it “shooting” out of the end of the hose. As @TheOldHokie says test the pressure with a gauge (3000 PSI range should be sufficient and not too expensive)

 

[Dashman]

Ok, I didn't buy a pump yet.

I closed the spool at the hydraulic block to focus on getting pressure at the 3PH. I manually raised it, and it could hold some weight with the valve closed or open with the lever raised. It was taking 1800 RPM for it to raise slowly.

Now what do you all think?

 

[TheOldHokie]

Ok, I didn't buy a pump yet.

I closed the spool at the hydraulic block to focus on getting pressure at the 3PH. I manually raised it, and it could hold some weight with the valve closed or open with the lever raised. It was taking 1800 RPM for it to raise slowly.

Now what do you all think?

I think you need to buy a gauge and test pump output pressure at the pump supply hose going to the loader valve. Its a $25, 10 minute test that will tell ypu something meaningful. Amazon would have this in my hands next day.

https://a.co/d/ioaHCj8

Dan

 

[Dashman]

1 to 3 day shipping on the gauge isn't the issue. It's the fitting to adapt the end of the hose to the gauge. I know, there's "kits" out there with quick disconnect couplers. I wanted to test without the FEL control valve. I found a 1/2" male JIC to 1/4" female NPT on Amazon, but its ETA was February 27. Then I found it on Ebay with an ETA of February 24, so I cancelled the Amazon fitting. This is just how it is living in a widespread rural community. You'd think with being the "low rider capitol of the world" that there would be one hydraulic shop, right? There are some tractor shops around me, but with so many tractors for them to service you wouldn't be seeing your tractor back any time soon. So I patiently wait. I'm hoping to have it back operational by March 1st, so I can start do some pasture work before it's time to irrigate.

In my searches for information on this forum, there were so many times that if someone just followed through by posting their results that it might have helped me. I don't intend on being one of "those guys". I'll post what fixed my issue, and make some suggestions to help the next guy go faster.

 

[North Idaho Wolfman]

1 to 3 day shipping on the gauge isn't the issue. It's the fitting to adapt the end of the hose to the gauge. I know, there's "kits" out there with quick disconnect couplers. I wanted to test without the FEL control valve. I found a 1/2" male JIC to 1/4" female NPT on Amazon, but its ETA was February 27. Then I found it on Ebay with an ETA of February 24, so I cancelled the Amazon fitting. This is just how it is living in a widespread rural community. You'd think with being the "low rider capitol of the world" that there would be one hydraulic shop, right? There are some tractor shops around me, but with so many tractors for them to service you wouldn't be seeing your tractor back any time soon. So I patiently wait. I'm hoping to have it back operational by March 1st, so I can start do some pasture work before it's time to irrigate.

In my searches for information on this forum, there were so many times that if someone just followed through by posting their results that it might have helped me. I don't intend on being one of "those guys". I'll post what fixed my issue, and make some suggests to help the next guy go faster.

I live remote these are all great places for hydraulics.

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[Dashman]

Discount Hydraulic Hose, that has been my go to hydraulic website, and their Thread ID Guide is helpful. For a few fittings, I don't mind ordering from them, but for just one fitting a guy can't beat free shipping. In this case, the quick delivery would have out weighed the cost. ...hind sight...

 

[North Idaho Wolfman]

Discount Hydraulic Hose, that has been my go to hydraulic website, and their Thread ID Guide is helpful. For a few fittings, I don't mind ordering from them, but for just one fitting a guy can't beat free shipping. In this case, the quick delivery would have out weighed the cost. ...hind sight...

Yes I always have to weight cost versus speed too.