Kubota b1550d hydraulic problem

[Ewee1991]

Okay I have a Kubota b1550d with loader that has such low hydraulic power it’s embarrassing. Okay when you turn on tractor the 3 point won’t even come up with my dad standing on it without throttle. Throttle does make the loader and 3pt go up but without throttle they both slowly come down. Been going on for a year. I need help I refuse to let it die bc it has 1500 hours on it. So far we have tried

: changing engine oil t6
:changing hydraulic fluid to Kubota synthetic
: cleaned hydraulic filter while we did it
: just changed hydraulic pumped today 350$ and thats it I give up.
:unplugged loader and the problem still persists as well

please help I’m begging somebody to point me in the right direction willing to give phone number to talk to somebody

 

[TheOldHokie]

Okay I have a Kubota b1550d with loader that has such low hydraulic power it’s embarrassing. Okay when you turn on tractor the 3 point won’t even come up with my dad standing on it without throttle. Throttle does make the loader and 3pt go up but without throttle they both slowly come down. Been going on for a year. I need help I refuse to let it die bc it has 1500 hours on it. So far we have tried

: changing engine oil t6
:changing hydraulic fluid to Kubota synthetic
: cleaned hydraulic filter while we did it
: just changed hydraulic pumped today 350$ and thats it I give up.
:unplugged loader and the problem still persists as well

please help I’m begging somebody to point me in the right direction willing to give phone number to talk to somebody

You need to do a hydraulic pressure test on the pump.

Dan

 

[Ewee1991]

You need to do a hydraulic pressure test on the pump.

Dan

What’s the pressure suppose to be when I do it?

 

[TheOldHokie]

I dont have the exact specification but something close to 2000 PSI. Do you know how to do the test?

Dan

 

[Ewee1991]

I dont have the exact specification but something close to 2000 PSI. Do you know how to do the test?

Dan

Me and my dad will figure it out gotta buy a psi gauge first tho

 

[TheOldHokie]

Me and my dad will figure it out gotta buy a psi gauge first tho

You might want to read the workshop manual - doing it incorrectly can break things.

Dan

 

[Ewee1991]

You might want to read the workshop manual - doing it incorrectly can break things.

Dan

Hopefully I can download one. This tractor was our first Kubota 15 years ago and prolly don’t have one i

 

[RCW]

Welcome to OTT.

First - - here is the parts diagrams for your tractor.

Kubota Tractor Corporation - Illustrated Parts List (kubotausa.com)

Second - - looks like some Workshop Manuals for some B1550 here - - VERY helpful resource. There are several models of B1550.

Kubotabooks.com

I'll try to get you started. There's about 17 (maybe 121) different things that be causing those issues.

Let's try to rule a couple out.....and we'll start with the real simple stuff....

Not sure how you're operating the tractor, but throttle is your friend with hydraulics.

Doesn't need to be wide-open (WOT), but you need some RPM to make the pump spin.....at least mid-throttle.

Did this just start suddenly a year ago?

My first thought was you've got a leak on the suction (inlet) side of your pump. The air it draws in can disable the hydraulic system. Normal is rubber-type hose. Won't leak, as no pressure. Just cracks will do it. Can often see some moisture near the crack if it's drawing air into the system.

 

[Ewee1991]

Welcome to OTT.

First - - here is the parts diagrams for your tractor.

Kubota Tractor Corporation - Illustrated Parts List (kubotausa.com)

Second - - looks like some Workshop Manuals for some B1550 here - - VERY helpful resource. There are several models of B1550.

Kubotabooks.com

I'll try to get you started. There's about 17 (maybe 121) different things that be causing those issues.

Let's try to rule a couple out.....and we'll start with the real simple stuff....

Not sure how you're operating the tractor, but throttle is your friend with hydraulics.

Doesn't need to be wide-open (WOT), but you need some RPM to make the pump spin.....at least mid-throttle.

Did this just start suddenly a year ago?

My first thought was you've got a leak on the suction (inlet) side of your pump. The air it draws in can disable the hydraulic system. Normal is rubber-type hose. Won't leak, as no pressure. Just cracks will do it. Can often see some moisture near the crack if it's drawing air into the system.

That’s definitely something I will look at tmr when I get off work when it’s light out excellent idea. I’m open to all ideas so I can check multiple things at once. It’s always been low hydraulic power for years but it really took a poop last year when digging holes and the hole digger won’t come out of the hole even with full throttle sometimes. It’s really bad. We really thought putting a new hydraulic pump would fix it haha.

 

[RCW]

Check the WSM and Parts diagrams - - I was thinking of my old 'Moline tractor when I spoke of suction side of the pump.

Not familiar with your tractor, so I hope I didn't send you down a rabbit hole. Cracks in hard lines would have the same effect.

Just so you know - - Dan, aka TheOldHokie is really good at hydraulic stuff. Great resource.

 

[Ewee1991]

Check the WSM and Parts diagrams - - I was thinking of my old 'Moline tractor when I spoke of suction side of the pump.

Not familiar with your tractor, so I hope I didn't send you down a rabbit hole. Cracks in hard lines would have the same effect.

Just so you know - - Dan, aka TheOldHokie is really good at hydraulic stuff. Great resource.

Excellent I’m very grateful for you and him taking the time to help me out this is amazing. I’ll tell my dad when we get a chance to buy psi gauge and I’ll look at those hydraulic lines tmr. Anymore ideas top of your head? I really appreciate everything so far

 

[RCW]

These are parts diagrams for a B1550D. There's also a B1550DHST.

I note there's a a couple sections of hose. 040 hose and the 050 clamps may deserve a look.

Also looks like a filter screen in the system - - 030 in other diagram. Has it been serviced/cleaned? A plugged filter could be problematic.

I'm no expert. Just tossing some ideas.... The WSM should help also. Guessing pulling the filter could dump all the fluid. My BX is a similar spot, but not seated in a banjo fitting.

 

[TheOldHokie]

Hopefully I can download one. This tractor was our first Kubota 15 years ago and prolly don’t have one i

Hopefully I can download one. This tractor was our first Kubota 15 years ago and prolly don’t have one i

I suggest the very first thing you should do is check the position of the selector lever on the hydraulic outlet block.

Dan

 

[Ewee1991]

These are parts diagrams for a B1550D. There's also a B1550DHST.

I note there's a a couple sections of hose. 040 hose and the 050 clamps may deserve a look.

Also looks like a filter screen in the system - - 030 in other diagram. Has it been serviced/cleaned? A plugged filter could be problematic.

I'm no expert. Just tossing some ideas.... The WSM should help also. Guessing pulling the filter could dump all the fluid. My BX is a similar spot, but not seated in a banjo fitting.

View attachment 88645


View attachment 88646

Ok today I checked the hoses there is one hose that looks old and peeling that I could replace and the clamps were loose so I tightened them up and still no better. And yes we cleaned that filter when we changed to synthetic Kubota hydraulic fluid.

 

[Ewee1991]

I suggest the very first thing you should do is check the position of the selector lever on the hydraulic outlet block.

Dan

View attachment 88649

Yup that part moves freely. Doesn’t that control the speed the bucket falls and raises?

 

[TheOldHokie]

Yup that part moves freely. Doesn’t that control the speed the bucket falls and raises?

No - that part is a selector valve that diverts the pump output to the loader. It MUST be in the loader position for the loader to work. If it is not fully set to the loader position strange things may happen. Read your owners manual!

Dan

 

[Ewee1991]

No - that part is a selector valve that diverts the pump output to the loader. It MUST be in the loader position for the loader to work. If it is not fully set to the loader position strange things may happen. Read your owners manual!

Dan

I understand but we disconnected the loader and the problem still persists that’s all. Atleast that’s what my dad told me. Thanks for responding quickly! I just read the manual. Now I understand each part. Thank you

 

[TheOldHokie]

I understand but we disconnected the loader and the problem still persists that’s all. Atleast that’s what my dad told me. Thanks for responding quickly! I just read the manual. Now I understand each part. Thank you

What do you mean by disconnected the loader valve? Simply moving the selector does not completely disconnect the loader. To do that you need to remove both hoses and plug the ports.

Did you get a pressure gauge? If not get one and use it to isolate the location of your problem:

Remove the supply hose at the loader valve and connect the hose to the pressure gauge. Make sure the selector is full over in the loader position then start the tractor. The gauge will show you full pump pressure which should be very close to 2000 PSI.

If you are not getting pressure the problem is in the pump, releif valve, or oil supply lines. At that point you start isolating and testing components on the up stream side side of the circuit..

If you are getting pressure the pump is fine and the problem is in the loader valve. At that point you move on down the circuit past the outlet block to isolate and test the loader valve.

If you move step by step along the circuit you will pinpoint the location of the problem. Right now you have way to many pieces in the circuit and you are guessing.

Dan

 

[Ewee1991]

What do you mean by disconnected the loader valve? Simply moving the selector does not completely disconnect the loader. To do that you need to remove both hoses and plug the ports.

Did you get a pressure gauge? If not get one and use it to isolate the location of your problem:

Remove the supply hose at the loader valve and connect the hose to the pressure gauge. Make sure the selector is full over in the loader position then start the tractor. The gauge will show you full pump pressure which should be very close to 2000 PSI.

If you are not getting pressure the problem is in the pump, releif valve, or oil supply lines. At that point you start isolating and testing components on the up stream side side of the circuit..

If you are getting pressure the pump is fine and the problem is in the loader valve. At that point you move on down the circuit past the outlet block to isolate and test the loader valve.

If you move step by step along the circuit you will pinpoint the location of the problem. Right now you have way to many pieces in the circuit and you are guessing.

Dan

The psi gauge will be here tmr! Is there a relief valve below the seat or location of relief valves? My dad wanted me to ask. He seems to think that’s a solution maybe. But we’re excited to start testing out with the psi gauge

 

[TheOldHokie]

The psi gauge will be here tmr! Is there a relief valve below the seat or location of relief valves? My dad wanted me to ask. He seems to think that’s a solution maybe. But we’re excited to start testing out with the psi gauge

The main system relief is in the outlet block on the right front of the tractor directly below the pump. As I said - start your testing there:

"Remove the supply hose at the loader valve and connect the hose to the pressure gauge. Make sure the selector is full over in the loader position then start the tractor. The gauge will show you full pump pressure which should be very close to 2000 PSI."

If you get pressure in that range the pump and system relief are fine and we can talk about were and how to conduct the next test.

If you don't get that pressure the pump or the relief are bad. That is a little harder to isolate.

Dan