How do You Test the Hydraulic Pressure on L345?

[FatLuckFarmer]

I need to test the hydraulic pressure on both the power steering pump, and the hydraulic pump. My power steering seems weak, and the 3pt doesn't move (stuck in the up position). I wanted to start with the pumps. The manual outlines a procedure for testing each but there is no real description, and the pictures are so dark and low resolution, I can figure out how to connect the pressure gauge. Both pumps have hard lines that are attached with o-ring'd flanges, and I don't see any port or place to put a guage. Can anyone help?

 

[North Idaho Wolfman]

Need some answers to be able to help better!

Does it have integrated power steering (lines go to the steering box) or does it have a booster setup (line go to a ram on the left side of the tractor.

Has the three point been working and died or is this an old issue?

Have you tried to turn the drop speed valve under the seat?

Does the tractor make any odd noises when you steer or when you try to lift or lower the three point?

The fact that the three point is up, tells me that there is or was flow and pressure at some point, and it not going down is not a pump issue, as it doesn't take fluid to drop it.

 

[rbargeron]

Most L345's with power steering have the integral setup in the column. Even new the power assist isn't strong. It has its own reservoir (above the engine) and uses the rear section of the dual pump. Check the oil level - uses regular hyd oil) The steering pump does not have a threaded test port.

The main hydraulic pump circuit does have a test port. Part 32 on attached pdf is a 1/4" pipe plug. With engine at 2600 rpm pressure should be approx 2100 psi with control lever full-up.

Does the three-point control lever move normally? If over-ranged in the up direction does it load the engine?

If the hitch is raised and won't drop, check the feedback rod on the left side lift arm for damage.

PM your email to me - I'll scan some WSM pages (high-res pdf's are too big for this site).

 

[SidecarFlip]

"The fact that the three point is up, tells me that there is or was flow and pressure at some point, and it not going down is not a pump issue, as it doesn't take fluid to drop it. "

But it certainly takes an operable flow control valve to relieve the oil pressure in the the upper link cylinder.... and they do tend to seize up from non use as well.

 

[Russell King]

Does the L345 have the speed control knob for the 3PH? Is it in the lock position?

Look for a knob that will be under the front of the seat (sitting on the seat it will be between your knees) on top of the transmission. Will have numbers or fast/slow and lock with arrows showing you which way to turn the knob.

Don’t force it if it doesn’t want to turn. Spray shaft into the housing with penetrating oil and work on it over days. It is fairly small diameter and can twist off easily.


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[rbargeron]

Here's a WSM illustration of the 3 pt cylinder unit under the seat. It has the drop rate valve and test port - plus relief valve, hydraulic block, optional valves.

 

[FatLuckFarmer]

Thanks guys.
The power steering is integral. Perhaps it's just weak? At a standstill turning the steering wheel feels like non power steering. Once moving it's pretty easy. I wasn't sure if as "power steering" it should make turning the wheel at a complete stop easier.

As for the 3pt. It has been up since I got the tractor. I had a frame mount backhoe on it which I just took off for the 1st time this winter. I tried turning the speed control for the 3pt both directions, and it makes no difference. FWIW The fluid levels in both the trans and the power steering reservoir are where they should be. I'll put a gauge on the test port, but because it's stuck in the up position perhaps I need to look at the flow control valve.

 

[rbargeron]

Thanks guys.
The power steering is integral. Perhaps it's just weak? At a standstill turning the steering wheel feels like non power steering. Once moving it's pretty easy. I wasn't sure if as "power steering" it should make turning the wheel at a complete stop easier.

As for the 3pt. It has been up since I got the tractor. I had a frame mount backhoe on it which I just took off for the 1st time this winter. I tried turning the speed control for the 3pt both directions, and it makes no difference. FWIW The fluid levels in both the trans and the power steering reservoir are where they should be. I'll put a gauge on the test port, but because it's stuck in the up position perhaps I need to look at the flow control valve.

The steering sounds similar to my L345's and L355ss. Airing up the front tires to 25-30 psi helps, but it will never have fingertip steering (like my L5450 or L48)

The position control valve is inside, bolted to the cylinder unit. Check that the lever is turning the rod (pin maybe sheared?) Leave the lever down and the drop speed valve several turns open - then try to force the arms down. Could have a sticky poppet.

 

[North Idaho Wolfman]

Thanks guys.
The power steering is integral. Perhaps it's just weak? At a standstill turning the steering wheel feels like non power steering. Once moving it's pretty easy. I wasn't sure if as "power steering" it should make turning the wheel at a complete stop easier.

As for the 3pt. It has been up since I got the tractor. I had a frame mount backhoe on it which I just took off for the 1st time this winter. I tried turning the speed control for the 3pt both directions, and it makes no difference. FWIW The fluid levels in both the trans and the power steering reservoir are where they should be. I'll put a gauge on the test port, but because it's stuck in the up position perhaps I need to look at the flow control valve.

If the three point has been up for a long time it very well may be stuck, they can get corrosion in the cylinders and piston and will need to be taken apart and honed.

You can pull the front cover and look at it.
also pulling the front cover it will drop if it's going to drop.

Very unlikely its a valve issue.

 

[Russell King]

I tried turning the speed control for the 3pt both directions, and it makes no difference.

Did you turn it to the fast side numerous turns until it hit the stop? It really takes a lot of turns on mine to get it to drop quickly if there is little weight on the arms. From what you say you may just have the short arms with no weight to move them down. You may want to hang weight on them


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[FatLuckFarmer]

If the three point has been up for a long time it very well may be stuck, they can get corrosion in the cylinders and piston and will need to be taken apart and honed.

You can pull the front cover and look at it.
also pulling the front cover it will drop if it's going to drop.

Very unlikely its a valve issue.

I think I have to take it apart. I finally got the chance to put a pressure gauge onto the port at the bottom of the 3pt speed control and with the engine at 2k rpm had 0 pressure. No reading at all on the gauge. I have an adjustable relief valve after the gauge and when I opened it (with the engine up) only a slight trickle of fairly dirty hydraulic fluid came out. The pump may not be in good shape but it looks like the system hasn't been used in years and may be totally toast.

 

[North Idaho Wolfman]

That actually tells me your not getting fluid to the piston.
It's either a valve issue, feed back or control linkage issue, or simply no pressure to the valve.

Have you tested the flow / pressure elsewhere?

There is a plug on the side of the Hydraulic cap (right side of the seat) that you can test the pump.

You have to remember it's an open system, so there will be flow but no pressure till something uses it.

 

[FatLuckFarmer]

That actually tells me your not getting fluid to the piston.
It's either a valve issue, feed back or control linkage issue, or simply no pressure to the valve.

Have you tested the flow / pressure elsewhere?

No That was the first test I did.

There is a plug on the side of the Hydraulic cap (right side of the seat) that you can test the pump.

You have to remember it's an open system, so there will be flow but no pressure till something uses it.

Well I have to rethink how far I want to get in to this...

The guy I bought it from swore he had dona a filter and fluid service fairly close to the time I bought this tractor. The oil looked clear and the hydraulic filters on the front loader and backhoe looked new. He may have done what he said, but he didn't do the trans/hydraulic for the 3pt. I know this because I decided to check the screen filter below the pump on the side of the engine just to be sure. I think I found my problem. aside from 6gal of rank looking hydraulic fluid, when i dropped the screen it was caked. Also 2 large chunks of metal fell out. Gear teeth! What ever failed, did so a while ago because there was about 2 table spoons worth of ground metal. Part of it rusty. the screen was caked with metal including very fine bits that felt like fine sand. I washed the screen and cap in the parts washer, but i don't know if I want to get into this further. I may just hope the trans is OK and accept that i wound be using the 3pt.

I'm really not sure what I should do now.

 

[North Idaho Wolfman]

Well I don't know how to put this, but I think your looking at some extensive repairs!

First that's a suction filter not a pressure filter so any metal or gear teeth in it are more likely from the tractor and not the pump.

The metal in it is almost surely from the tractor.

Depending on what loader and what BH are on it they could very well be running with the same nasty fluid that is in there.
And if you didn't know it, that's the same fluid for the entire transmission, axles, differential, and hydraulic system, it's a common sump.

I would drain the entire tractor, 4 or 5 drain plugs, will drain all of it.
flush with new cheap fluid, then replace fluid with good quality fluid.
I would also drain and service the front axle too, bet it's just as bad.

 

[FatLuckFarmer]

Well I don't know how to put this, but I think your looking at some extensive repairs!

First that's a suction filter not a pressure filter so any metal or gear teeth in it are more likely from the tractor and not the pump.

The metal in it is almost surely from the tractor.

Depending on what loader and what BH are on it they could very well be running with the same nasty fluid that is in there.
And if you didn't know it, that's the same fluid for the entire transmission, axles, differential, and hydraulic system, it's a common sump.

I would drain the entire tractor, 4 or 5 drain plugs, will drain all of it.
flush with new cheap fluid, then replace fluid with good quality fluid.
I would also drain and service the front axle too, bet it's just as bad.

Yeah. After sleeping on it, I would agree with you. This poor tractor has had a very hard life. FWIW the loader and BH each have discrete hydraulic systems. The only thing this pump runs is the 3pt, but of course it's running through the trans. That unfortunately may be where those 2 gear teeth came from. The tractor does drive fine. The engine is strong, the clutch and brakes are good and till I found those teeth, I didn't think that there might be a problem with the trans. I'll drain and flush what I can, get her back together and do as much work with her till something major goes boom. I just rebuilt the BH and Loader so I think she's worth a little more TLC.
Thanks for your help.

 

[rbargeron]

.....The only thing this pump runs is the 3pt, but of course it's running through the trans. That unfortunately may be where those 2 gear teeth came from.....

A positive view here might be the debris in the filter may be from a long time ago. The tractor is +/- 40 years old. Its possible an old pto gear failure got fixed without flushing out the trans oil. And with loader & hoe using a separate system, the original filter has been idling, slowly accumulating condensation rust and metal debris in the filter, which has been trying to do its job the whole time?

 

[Russell King]

Those teeth may be from a previous failure that was repaired. I agree that filter didn’t show anything that gives you a lot of hope the tractor was well maintained but if you need the 3PH to work it may not take too much time to investigate it and figure out what needs repair and if it is available for a reasonable price.

Good luck


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