B1550 questions

half track · May 17, 2018

Have a b1550hst that I just picked up and have questions on it. I just changed engine oil and transmission oil. Cleaned the strainers on both side which did not have much to clean off. I also changed the tranny filter and replaced oil with udt from Kubota. It seems to have power in low gear and doesn’t whine too bad. I drove it up a steep hill and it spun rear tires without having 4wd locked in. A little noisy under load but it climbs. On flat ground it goes in high but really whines. Is this normal to be this gutless in high? I sure couldn’t climb a hill in high. Has 845 hours on it. It does have a little miss at full throttle but I haven’t changed the fuel filter yet and might switch out injectors.

Any thoughts? I have a little b5100d and it seems a little more powerful.

Last question. When I push in clutch nothing changes. Perhaps my plate is rusted to flywheel? I will grease throw out bearing as I saw that in manual. This thing sat for quite a while.

Thanks for any help

half track · May 17, 2018

Ok a couple observations. When I got it the engine oil was way high. I drained and replaced with filter. I have not checked again but if high is it possible the pump is pumping oil into the engine due to bad seal?

I drove again and with a mower on it this thing would either be too slow to use in low or too wussy to mow in high with a little hill. No way a craftsman should be the better choice here. I know this is not a powerful animal but should be more powerful than a lawn tractor.

Can I check pump psi anywhere and what should it be. Just have operators manual and will order service manual.

Thanks.

Another thought. This thing has a loader. If sometime someone dead headed it by turning valve to loader while not hooked up where would pressure go. Blowout pump seal?

half track · May 17, 2018

Checked engine oil. Not above the full line more than 1/8 of an inch after sitting. Damn

North Idaho Wolfman · May 17, 2018

half track said:
Ok a couple observations. When I got it the engine oil was way high. I drained and replaced with filter. I have not checked again but if high is it possible the pump is pumping oil into the engine due to bad seal?

I drove again and with a mower on it this thing would either be too slow to use in low or too wussy to mow in high with a little hill. No way a craftsman should be the better choice here. I know this is not a powerful animal but should be more powerful than a lawn tractor.

Can I check pump psi anywhere and what should it be. Just have operators manual and will order service manual.

Thanks.

Another thought. This thing has a loader. If sometime someone dead headed it by turning valve to loader while not hooked up where would pressure go. Blowout pump seal?

Yes a bad pump seal will pump hydraulic fluid into the engine oil, good thing is it won't hurt the motor.
Yes dead heading the system can cause it to blow a seal, most hydraulic blocks are "smart" and cause the pressure relief valve to kick in before it does damage.

Check the pressure at one of the outputs for the cylinders for the FEL.

You can get The WSM off of Kubotabooks.com for free.

half track · May 18, 2018

Thanks for the responses. So test the port on the loader. What should psi be?

I am thinking I need to replace the hydraulic pump but will check psi. Should have more power than this.

half track · May 18, 2018

Can the pump pressure be adjusted? Of course to just get to pressure goal.

North Idaho Wolfman · May 18, 2018

half track said:
Can the pump pressure be adjusted? Of course to just get to pressure goal.

half track said:
Thanks for the responses. So test the port on the loader. What should psi be?

I am thinking I need to replace the hydraulic pump but will check psi. Should have more power than this.

Engine at 2600 RPM pump should build 1920 PSI.

Yes the pressure of the pump is controlled by shimming the Relief valve.

half track · May 20, 2018

Ok. Hope this isn’t a stupid question then. Am I on the right track that if I test the pressure and it is low by shimming it at the relief valve it will increase pressure and will make a difference in power for the hst transmission? I don’t much care about loader operation just want to be able to go up hills in high setting. Three point works fine and tractor moves just acts like i am trying to drive it with too low rpm even when rpm is up to where it should be.

Thanks for the help.

North Idaho Wolfman · May 20, 2018

half track said:
Ok. Hope this isn***8217;t a stupid question then. Am I on the right track that if I test the pressure and it is low by shimming it at the relief valve it will increase pressure and will make a difference in power for the hst transmission? I don***8217;t much care about loader operation just want to be able to go up hills in high setting. Three point works fine and tractor moves just acts like i am trying to drive it with too low rpm even when rpm is up to where it should be.

Thanks for the help.

Negative, the HST does not rely on the main hydraulic pump for it's pressure, or performance, it has it's own pumps and relief systems.

Go out and try this with the tractor, climb a hill, when it starts to slow down, instead of pushing on the pedal, ease up on it, I think you will be real surprised on what happen.

Do you have a PTO driven implement?
It could be possible that the clutch is going out and not spinning the HST fast enough when in high.
One way to test this is put some PTO powered implement on it and while pushing like up a hill in high when it slows down check PTO operation, if it also slows down you have a clutch issue.
Another way to check it is to remove the cover over the propeller shaft, Paint a white line on the shaft in a spiral, this allows you to get a basis for speed of the shaft spinning, Make 1000% sure that no clothing or any part of you touch the shaft when it's spinning, I don't want to tell you what can happen to you if that were to happen!

half track · May 21, 2018

I am certain the clutch is not slipping as the plate is stuck right now. I push the clutch pedal while driving and nothing happens. I am going to replace it but not until I figure out the transmission issue. I will try driving it up hill and ease up on the pedal but not sure what that will tell me. I had removed the main screen and cleaned it but will go ahead and order a new one to make sure. As of now that is my only plan. After that?

So a pressure test on the loader port won’t tell me anything pertaining to the transmission? The pump on the side doesn’t affect it?

North Idaho Wolfman · May 21, 2018

half track said:
I am certain the clutch is not slipping as the plate is stuck right now. I push the clutch pedal while driving and nothing happens. I am going to replace it but not until I figure out the transmission issue. I will try driving it up hill and ease up on the pedal but not sure what that will tell me. I had removed the main screen and cleaned it but will go ahead and order a new one to make sure. As of now that is my only plan. After that?

So a pressure test on the loader port won’t tell me anything pertaining to the transmission? The pump on the side doesn’t affect it?

Just because the clutch won't release with pushing the pedal does not mean it's not slipping, you could have a damaged throw out bearing, pressure plate and a damaged clutch disk.

No the main hydraulic pump has no effect on the work that the HST can perform, yes on some models the main pump being out will make it seam like the HST is out because they use the charge pump for the HST.

Now if the main pump is sucking that will put air in all of the fluid and effect HST performance.

half track · May 21, 2018

Ok. Great info.

I was checking for slipping by putting it in low and climbing a steep hill with the clutch pedal pushed in. I was thinking that if it would slip it would do that with a load like that. My strategy right now is to replace that main strainer, the o rings on that fitting and check the pipe hose as the pump for leaking. Probably replace it.

I had cleaned the strainer by blowing it out but it has a brown thing inside it that I presume is to help the strainer hold its shape. Maybe it is a little clogged. If that doesn’t work I will change the main clutch. Anything else I can do?

Thanks for the continued help. I do appreciate it.

North Idaho Wolfman · May 21, 2018

half track said:
Ok. Great info.

I was checking for slipping by putting it in low and climbing a steep hill with the clutch pedal pushed in. I was thinking that if it would slip it would do that with a load like that. My strategy right now is to replace that main strainer, the o rings on that fitting and check the pipe hose as the pump for leaking. Probably replace it.

I had cleaned the strainer by blowing it out but it has a brown thing inside it that I presume is to help the strainer hold its shape. Maybe it is a little clogged. If that doesn’t work I will change the main clutch. Anything else I can do?

Thanks for the continued help. I do appreciate it.

You could read the WSM and it has all the steps for testing the HST, you might be able to test the pressures of the HST, some require special fittings and adapters to do it, so that might stall you on that.

alchemysa · May 22, 2018

In high range my B1550 HST can barely climb over its own shadow. Its only about 14hp when brand new remember. A worn HST is going to waste a lot of that hp as it gets older.

That business about something being in the HST wire mesh screen sounds odd. I don't remember anything like that in mine, although its quite a while since I looked at it.

So you are starting it 'in gear'?

half track · May 22, 2018

Yes. I start it in gear. Clutch pushed but it spins fine.

I ordered a new strainer and o rings. I will replace it and see what that does. I am going to grease the throw out bearing and tie the clutch pedal back then drive the crap out of it to see if the clutch plate is rusted to the flywheel. If that doesn’t work I will replace it.

half track · May 22, 2018

One more question. After running for a while at about 2500 rpm and at normal operating temps it develops a miss like one cylinder is missing. I have not changed the fuel filter and that is my next project. Could a clogged fuel filter do this? It has sat a lot and has 845 hours on it. After that will start looking at injectors. I am enjoying working on this machine.

North Idaho Wolfman · May 23, 2018

Highly unlikely that it's the fuel filter.
If it's missing it's either the valve adjustment, bad injector, or much less likely bad injection pump.

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