Hydraulic Relief Valve Adjustment for Bx2230 and Bx1830

[Tractor Seabee]

I raised the pressure on my BX25 to 2000 PSI; what a difference, especially in the FEL operation. Factory spec is 1778-1849 PSI. Kubota only uses one relief valve for all the SCUTs. Pressure is changed by adding or subtracting shims under the spring. Each 1 mm added changes pressure 39 PSI. WSM shows how to do all that. If you follow the hydraulic system in the WSM you will see it only affects the attachments not the transmission as it has its own pressure regulation. Increasing the pressure will make the relief valve a little noisier for awhile then it dies out. I made a gauge unit using a forged steel 3/8 IPT tee with a 1/4 branch. male and female QCs on each end and gauge in the branch. Kubota uses standard Parker QCs available at most HYD shops. Surplus Center does not sell them. Connect it temporarily in the power line for the BH as that is the first outlet in the PB string..

JJ there is some more info for your vast data base.

 

[CHDinCT]

I raised the pressure on my BX25 to 2000 PSI; what a difference, especially in the FEL operation. Factory spec is 1778-1849 PSI. Kubota only uses one relief valve for all the SCUTs. Pressure is changed by adding or subtracting shims under the spring. Each 1 mm added changes pressure 39 PSI. WSM shows how to do all that. If you follow the hydraulic system in the WSM you will see it only affects the attachments not the transmission as it has its own pressure regulation. Increasing the pressure will make the relief valve a little noisier for awhile then it dies out. I made a gauge unit using a forged steel 3/8 IPT tee with a 1/4 branch. male and female QCs on each end and gauge in the branch. Kubota uses standard Parker QCs available at most HYD shops. Surplus Center does not sell them. Connect it temporarily in the power line for the BH as that is the first outlet in the PB string..

JJ there is some more info for your vast data base.

Good info TS. For those of us without a WSM would you mind telling us where the relief valve is? I want to tweak mine also. Already have a pressure gauge set up, just not sure where the valve is.

 

[Tractor Seabee]

I am being a nice guy for a change, I normally say go buy your own manual. Here are 3 pages from the WSM depicting the relief valve. The picture is not very definitive on the location. It is on the left side of the HST behind the left rear wheel. Recommend you have the BH and the wheel off to do this. Once you see the HST you will recognize the hex cap for the valve. Simple process. Check current pressure, subtract from where you want to be, determine from the difference what shims you need. They are only a few cents a piece. Your dealer will probably have to order. My dealer has a large shop in business many years and they have never ordered shims. They refuse to set pressure above factory recommendation for anybody, in warranty or not. They claim it is a liability factor. They will not sell wheel spacers for the same reason.

Buy the manual if you plan to do any work yourself. There are a lot of troubleshooting tips in there. I have 1000 hours in 3 years on a BX25 and that manual has saved me numerous 40 mile trips one way to the dealer shop Haven't been there yet. Coming up though, I have let some things accumulate that are covered under the KTAC casualty insurance plan. They are jobs I do not want to tackle. It is actually cheaper to fix stuff myself rather than lose 2-4 weeks production time sending to the shop. I figure the trip alone 2 ways is worth $500 off the top.



Ron

 

[kennyd]

Here is a video I made on testing the PRV with a simple pressure gauge, it's on a green tractor but the theory is the same.

Hydraulic Pressure Test Gauge, Use and Operation - YouTube

 

[CHDinCT]

I am being a nice guy for a change, I normally say go buy your own manual. Here are 3 pages from the WSM depicting the relief valve. The picture is not very definitive on the location. It is on the left side of the HST behind the left rear wheel. Recommend you have the BH and the wheel off to do this. Once you see the HST you will recognize the hex cap for the valve. Simple process. Check current pressure, subtract from where you want to be, determine from the difference what shims you need. They are only a few cents a piece. Your dealer will probably have to order. My dealer has a large shop in business many years and they have never ordered shims. They refuse to set pressure above factory recommendation for anybody, in warranty or not. They claim it is a liability factor. They will not sell wheel spacers for the same reason.

Buy the manual if you plan to do any work yourself. There are a lot of troubleshooting tips in there. I have 1000 hours in 3 years on a BX25 and that manual has saved me numerous 40 mile trips one way to the dealer shop Haven't been there yet. Coming up though, I have let some things accumulate that are covered under the KTAC casualty insurance plan. They are jobs I do not want to tackle. It is actually cheaper to fix stuff myself rather than lose 2-4 weeks production time sending to the shop. I figure the trip alone 2 ways is worth $500 off the top.

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Ron

TS - Thank you very much for posting excerpts from your WSM. That's way more than I expected - was just hoping for a pic of where the valve stack is. I've held off getting a WSM thinking I'll get one when/if I need to do a major repair. I have almost 400 hours in three years on my BX25, so not racking them up as fast as you, but it does get used quite a bit. I'm going to be adding the Kubota QA for the FEL which will reduce my lift capacity so I'm thinking I'll push the pressure up just a bit - maybe 1900+/- to offset that a bit. Last I checked, my pressure was on the low side of spec, so I could use a little boost anyway.

 

[CHDinCT]

Here is a video I made on testing the PRV with a simple pressure gauge, it's on a green tractor but the theory is the same.

Hydraulic Pressure Test Gauge, Use and Operation - YouTube

Kennyd - you're a star :thumbsup: I assume that's you in the video? I actually bought my pressure gauge years ago to test the pressure on my old JD X485 when I added a 45 loader to it. Ended up bumping the pressure up on that machine just a little. Just had to change out the quick connect on it to work with my BX. Oddly, Kubota puts the male QC's on the tractor side for the FEL whereas JD puts female QC's on theirs (for SCUTS anyway). So, I changed out to a female parker style to check the relief pressure on my BX via the FEL ports. But, about a year or so ago, I added a dual spool valve at the rear for rear remotes. That valve has it's on relief valve and of course has female QC's on the valve side, so now I need to make up a hose extension with two male ends to check the pressure setting in the Prince Wolverine valve. Anyway, point is I think Kubota is a bit unique putting male QC's on the tractor-side FEL hookup.

 

[kennyd]

Kennyd - you're a star :thumbsup: I assume that's you in the video?

Yes, thats me...

Anyway, point is I think Kubota is a bit unique putting male QC's on the tractor-side FEL hookup.

Is that what they call it nowadays, unique? :laughing:

Seriously though, Bxpanded sells a nice kit for the Kubota's, it even includes some shims: Hydraulic Pressure Tester

My point of posting the video was just to show people how to do it, hopefully some will find it useful.

 

[Kerton]

Useful information. Thanks to you all.

Anybody here able to tell me more about the dimensions of the shims? Specifically the diameter. Or where i can get them online? My dealer sucks, and is also far away.

Thanks.

 

[Tractor Seabee]

Messick's one of the big advertisers on TBN does a big mail order business. Other posters here use them and give big hurrahs to them. There are 3 thicknesses, .1, .2, & .4 mm. Each .1 mm changes the pressure 39 PSI. My dealer, Jennings Equipment will mail them to you also. They are listed on the K website.

Ron

 

[Kerton]

Thanks, Ron. I've used Messick's before for mail order. But it seems like every mail order from a dealer is a 10 day waiting game. I bought a Rear Aux hydraulic kit from them, which worked out well, but there was no tracking number, no receipt, nada. Just me giving a credit card and a wing and a prayer over the phone. Also, I could not search the part out on their website, so it'll take a phone call during east coast business hours. It was a bad retail experience, but it did work.

I've also bought a fair bit from Harry at BXpanded. It seems like every month, I carve a slice out of my paycheck for him!! Mostly because he has good stuff I realize I need bit by bit. I'm waiting for the Piranha teeth to arrive as we speak. That said, I already have a pressure meter, and don't want the whole BXpanded shim kit.

I was wondering if anyone had any suggestions for easier, hardware store-type substitutes. Like, I could grind down a washer if I knew what the diameter was supposed to be. Best answer for me would be either the diameter, so I can hunt on my own, or a direct hyperlink like this:
Amazon.com: The Hillman Group 44996 M6 Metric Stainless Steel Fender Washer, 12-Pack: Home Improvement

...but of course, I know that is the wrong size, but the right hyperlink would be a lot easier than calling up Messick's and shipping. Thanks in advance if anyone else can help.