B1750HST lost hydraulic power to 3pl and power steering

[Aussietrac]

G'day from Australia! I've recently picked up this B1750 that seemingly has no hydraulic pressure to either the power steering or 3 point hitch. The fluid level is correct on the dipstick. The rest of the tractor functions fairly well and the HST transmission seems to work as expected.

The previous owner has had some work done to recondition the injector pump and claims that the hydraulics all worked before that work.

Is there anything that I can check with basic tools (spanners and sockets etc) or will I be needing specialist guages and flowmeters? I have some basic knowledge of hydraulics but I'm certainly no mechanic.

Thanks

 

[Dave_eng]

There is a hydraulic block on the right side of the tractor. Shown in your picture which I have marked up.

The yellow arrow is pointing to a pin used to rotate a selector valve.
Try rotating the pin until it hits the vertical stop.
If that does not make things work, don't leave it in the new position as I have not studied the hydraulic section of the shop manual.
You can download the WSM for free at this link.
Kubotabooks

Was there a loader on this tractor as the rusty patches are where a loader would be mounted?
The selector on the hydraulic block would have been used like an A B switch to send flow to basic systems or to the loader.
Please post if this advice helps as everyone learns.
Dave

 

[Aussietrac]

Thanks Dave,

Please see attached screenshot of the WSM. You are correct in that the diverter valve that you marked is for an auxiliary implement such as a loader. I'm not sure if a previous owner had a loader attached but it does look that way by the wear where the rust is. Anyway, by the diagram in the WSM, it's in the correct position to power the 3PL and power steering.

Today I backed off the nut on the high pressure side of this valve that goes to the power steering pump. It was suggested on another forum that hydraulic fluid should be pumped out with force when the tractor is running. No fluid came out other than the tiniest couple of drops under no pressure.

I backed off the inlet bolt to the hydraulic pump and found what looked like the correct level of fluid in there on the intake side of the hydraulic pump.


On further investigation, I found that the hydraulic pump was missing one of the screws (marked "3") in the diagram of the hydraulic pump attached. This to me indicates that the hydraulic pump has been opened before and possibly unprofessionally.

I wonder if it's the pump at fault. I would've thought that a pump at that high pressure would be relying on an absolute seal in the pump.

 

[Thunder Fish]

Good sleuthing and welcome !

 

[TheOldHokie]

Thanks Dave,

Please see attached screenshot of the WSM. You are correct in that the diverter valve that you marked is for an auxiliary implement such as a loader. I'm not sure if a previous owner had a loader attached but it does look that way by the wear where the rust is. Anyway, by the diagram in the WSM, it's in the correct position to power the 3PL and power steering.

Today I backed off the nut on the high pressure side of this valve that goes to the power steering pump. It was suggested on another forum that hydraulic fluid should be pumped out with force when the tractor is running. No fluid came out other than the tiniest couple of drops under no pressure.

I backed off the inlet bolt to the hydraulic pump and found what looked like the correct level of fluid in there on the intake side of the hydraulic pump.


On further investigation, I found that the hydraulic pump was missing one of the screws (marked "3") in the diagram of the hydraulic pump attached. This to me indicates that the hydraulic pump has been opened before and possibly unprofessionally.

I wonder if it's the pump at fault. I would've thought that a pump at that high pressure would be relying on an absolute seal in the pump.

No need to guess. Spend $20 USD on a 5000 PSI hydraulic pressure gauge and the appropriate adapter fitting and test pump output pressure.

You do that at the outlet block mentioned earlier. With the engine off remove the rightmost plug and using the adapter screw the gauge into the port. Then move the selector lever on the block to the implement position, start the engine, and read the pressure. Do not operate the tractor for more than a minute or two. Shut the engine off, replace the plug, and move the selector lever back to the 3pt position. You should be getting roughly 2000 PSI at rhat test point.

Dan

 

[Dave_eng]

Some owners have had success in getting a sluggish pump to start pumping by using a shop vac to pressurize the fluid reservoir. The shop vac, by design, is very limited in the pressure it can generate but sometimes it is enough to get things moving.
Dave

 

[North Idaho Wolfman]

It sounding like you have an issue with the pump, possibly a drive failure.

 

[Aussietrac]

Bit of an update from today's works. I pulled the hydraulic pump off today to find the drive tang on the pump broken. Well done North Idaho Wolfman, hit the nail on the head!

Is there anything in particular that I need to remedy that may have caused the tang to snap before I bolt a new pump on? Or could it just be general wear and tear/fatigue?


I'll be looking for a replacement pump now. From the parts manual, the part number is 67810-76100. Any suggestions for oem pumps would be appreciated. I figure that the genuine Kubota part in Australia could be astronomical in price.

 

[TheOldHokie]

Bit of an update from today's works. I pulled the hydraulic pump off today to find the drive tang on the pump broken. Well done North Idaho Wolfman, hit the nail on the head!

Is there anything in particular that I need to remedy that may have caused the tang to snap before I bolt a new pump on? Or could it just be general wear and tear/fatigue?


I'll be looking for a replacement pump now. From the parts manual, the part number is 67810-76100. Any suggestions for oem pumps would be appreciated. I figure that the genuine Kubota part in Australia could be astronomical in price.

White House Products Ltd in the UK seems to be a good source for replacement pumps. They list GPO120R (clockwise) and GPO120L (anti- clockwise) as replacements for that Kubota part number.

Search Results - White House Products, Ltd

Discover how White House Products Ltd. has emerged as UK's premier supplier of hydraulic parts, motors, accessories, and pumps, boasting an extensive inventory.

www.whitehouseproductsltd.com

You have to register with them to get pricing. My quoted price is 67 pounds plus VAT if applicable. Even with international shipping to me here in the USA with no VAT and current USD exchange rate that's still dirt cheap.

Dan

 

[TheOldHokie]

That WOW reacct

White House Products Ltd in the UK seems to be a good source for replacement pumps. They list GPO120R (clockwise) and GPO120L (anti- clockwise) as replacements for that Kubota part number.

Search Results - White House Products, Ltd

Discover how White House Products Ltd. has emerged as UK's premier supplier of hydraulic parts, motors, accessories, and pumps, boasting an extensive inventory.

www.whitehouseproductsltd.com

You have to register with them to get pricing. My quoted price is 67 pounds plus VAT if applicable. Even with international shipping to me here in the USA with no VAT and current USD exchange rate that's still dirt cheap.

Dan

That WOW reaction is right - Messicks wants $762 USD (£670) for that pump!!!!

The B1750 replaced the B8200 which used that same Kubota pump/part number. The White House GPO120L pump in anti-clockwise riotation has been used as a replacemtn with good results by a number of other folks here. Plenty of discussion of that in the archives.

Dan

 

[Russell King]

If you trust that the pump will work you may be able to find parts to repair the existing. But may still be more expensive than replacing the whole pump.

Check for used parts with tractor salvage yard?

 

[fried1765]

If you trust that the pump will work you may be able to find parts to repair the existing. But may still be more expensive than replacing the whole pump.

Check for used parts with tractor salvage yard?

Apply the KISS principle! (is that acronym understood down under?)
Order the new pump from Whitehouse in the UK!

 

[Aussietrac]

Thanks everyone, I have applies the KISS principle and ordered a new anti-clockwise GPO120L equivalent pump from Whitehouse in the UK. Hopefully won't take too long to get all the way to Australia.

 

[TheOldHokie]

Thanks everyone, I have applies the KISS principle and ordered a new anti-clockwise GPO120L equivalent pump from Whitehouse in the UK. Hopefully won't take too long to get all the way to Australia.

You know it just occured to me - maybe as you are "down under" perhaps you need the clockwise pump

I purchased one pump from WH and it crossed the Atlantic in less than a week.

Dan