FEL issues

[jeeping]

kubota L275DT with a BF400 loader. 3Pt works fine, curl works fine, loader going up it slow but can lift 600lbs +/- nothing more.
hydro pump has a whistle type noise when running. Kinda loud. I had all the cylinders on the loader rebuilt few years ago. I then changed fluids and filter. I changed out the quick disconnect hose fittings. I pulled the joystick and relief valve apart and cleaned. Nothing changed.

I flipped the hoses around from curl to up and down. Seemed like the loader went up faster but when I went to come down it would only drop a few feet then start to go back up. I had to shut tractor off to drop all the way down. I pulled hoses apart and blew the out. Everything look good.

I then replaced the hydro pump and everything is nice and quite. Until i use the loader. lift up and curl up make a whining noise like is its starving. When 3pt hitch goes all the way up. The motor comes under a load, you can hear it.
I pulled the 3pt speed control apart and everything looks good.

 

[Roadworthy]

Do you have your three point lever in the full up position? If so move it to lower a wee bit. You may have your hydraulics at the limit and going into bypass mode.

 

[oldnslo]

Like roadworthy states try lowering the three point some. If loader now works your 3 point feed needs adjusting. Both halves of quick disconnects can fail so just changing hose end may not solve the problem if it is a QD failure.

Is pump quiet when loader is not in use?

 

[jeeping]

yes i tired it with the 3pt lever in all positions. I changed the quick disconnects complete both sides.
yes pump is quiet when loader isn't in use

is it possible a hose on the loader could internally clasped in use? I've seen it happen with fuel lines

I wonder if i'm air bound. Ive let it run for several hours in hopes the air would work its way out

 

[oldnslo]

Do you have capabilities of installing a pressure gauge in the pressure line to the loader valve? If yes watch the pressure while you raise and lower and or curl and dump. This will provide some insight on what pressure is doing. If getting close to relief pressure that could be the noise you are hearing.

When using the loader watch the hoses to see if both hoses stiffen and swell while trying to raise or just the one.

If both hoses stiffen then there is a restriction in the rod end line going to the valve or lesser possibility something in the valve tank line. If something in valve tank line you could possibly damage the valve if tank pressure gets to high.

 

[rScotty]

Sounds like you have done a lot of work without anything fixing it. Maybe some more history and information would help. .

When did the problem with the loader start? Or did it ever work right? Is your L275DT one with the optional power steering, hydraulic remotes, mower hydraulics, or any other additions to the hydraulic system? If so how are those workiing?

In general, hydraulic pumps are very quiet. If the flow is restricted too much, you get very high pressure and will hear the overload valve as well as the pump. Hearing either one means shut her down and find the blockage before running it more.
Amazon sells hydraulic test gauge kits with "T" adapters to fit any common quick disconnect for around a hundred dollars. You would want one with 5000 psi capacity.

Insert the T fitting into any quick disconnect dydraulic line. It can stay there indefnitely. Check the pressure in that line when that line is operating vs not being used.

luck, rScotty

 

[jeeping]

Yes this weekend I’ll install a gauge, no power steering.

Long read
Here’s the backstory this was my father’s tractor and I believe the loader started this back 20 years ago being slow and not lifting max weight.

About 15 years ago I went thru the tractor and replaced the hydraulic pump. At that time I thought it was air bound so while the tractor was running I back off a few bolts on a high pressure line, just enough so I could lift it. I did real quick and had fuild shoot out and it made a squeal sound and I bolted it back up.
The pumped remained loud while tractor was running but the loader worked great. Couple days later I lifted a huge white oak log and drove up out of the woods with counter weight on tractor.
When I got to the log pile I decided to see how high I lift and too my amazement it went all the up then the tractor made a loud sound from the pump and I shut it down.
I pulled the pump and the spline shaft coming out the back of the pump was twisted and the gear in the motor broken. I replaced the motor parts and replaced the spline in the pump with the one from my original pump.
The pump was still loud and everything worked slow and not at max weight again.
I ended up buying a bigger tractor and parked this one. Now I went to open up room and get rid of it so I started going back thru it.

 

[jeeping]

So I checked the pressures. Incoming to loader control I have 1700psi and the same at both the bucket curl and loader up and down circuits
The pressure stayed the same regardless what rpm was at

 

[jeeping]

So I decided to change the hydraulic filter and now I have 1900 psi and everything seems to be good.

the high-pitched noise I was hearing when I was trying to use the loader which I thought was air ended up being that I was just starving for fluid.
It’s Werid because I just changed the the filter at the start of this.did so many different things.
I tested lifting a red oak log 10’x 20” diameter. I was able to lift it 5’ off the ground and curl it up all the way.

 

[rScotty]

So I decided to change the hydraulic filter and now I have 1900 psi and everything seems to be good.

the high-pitched noise I was hearing when I was trying to use the loader which I thought was air ended up being that I was just starving for fluid.
It’s Werid because I just changed the the filter at the start of this.did so many different things.
I tested lifting a red oak log 10’x 20” diameter. I was able to lift it 5’ off the ground and curl it up all the way.

What kind of pressure measuring setup did you end up using? For our old JD I used a hydraulic "T" fitting - which looks pretty much identical to a plumber's T, but machined instead of cast. That T fitting is mounted anywhere in the line between the hydraulic pump pressure side and the "IN" port of the loader control valve. Then the gauge threads into the middle of the T. Ours has been on the tractor for some 20+ years now.....so long that I've forgotten why I put it there in the first place. Probably simple curiosity.

Pressure at the output from the pump should be very low when nothing is being actively lifted by the loader or 3pt. Theoretically pressure should be near zero when no load is being lifted, but there is always friction when fluid flows through a hose. If the gauge shows more than a few hundred pounds when nothing is being lifted then there is a problem somewhere that needs fixing.
1900 psi is about right for that tractor & loader when it is lifting.

Glad you found the problem. After years as a mechanic and shop owner, I found that when a hydraulic pump starts making noise by whining and complaining along with a loss of lifting power it is almost always that the pump is starving for fluid. Either it is an air leak in the suction hose to the pump, fittings, or a bad filter. The noise the pump makes is diagnostic once you hear it & easy to recognize again. The good news is that the fix is inexpensive.
Congrats,
rScotty