Kubota B2601 Loader Pressure Adjust

[Rock Crawler]

My buddy at work has a 2018 Kubota B2601 and he was telling me that he is unhappy with the weak loader and general poor performance of the loader hydraulics. He was saying that he is considering trading it for a B2650 or an L2501 and taking a big loss on his nearly new B2601. So... I offered to crank it up a bit. He was excited to do this.

I did explain that while turning it up, you may possibly shorten the ultimate life span of the cylinder seals and could potentially shorten the life of the hoses.... He agreed that there is a chance, and he really does not care since the B2601 sucks as it came to him and he is very unhappy....

So I started out by gauging the system to see what it looks like at full RPM as it was delivered to him. The goal was to get it up 500 PSI over the starting point. So we attached the BXPANDED.com gauge to the lowest of the 4 loader quick disconnects, this is the line that sees pressure when you pull the lever straight back at yourself to raise the loader boom up into the air. The starting pressure was right at around 1960 PSIG.

So we pulled the pressure relief valve cap and pulled the coil spring out of the cap, inserted a Kubota 4 mil shim into the cap and replaced the spring, then put it back and re-tested. With 1 4 mil shim we got to 2100 PSIG.

We pulled the gauge and he went out to dig into his pile of gravel, he said that it was barely perceptible as being better.... He wanted more. Okay. We really only came up 150 PSI or so....

So back in and put the gauge on, pull the cap, put a second 4 mil shim under the spring (shim goes into the cap, then spring into cap and against the shims) and put it back on, ran it up and pulled a pressure reading. Now we are seeing 2350 PSIG. He ran back out to test and said that this made a noticeable change, and one that he liked.... a lot! So for now we stopped here with 8 mil of total shim and right at 400 PSI increase.

I have attached photos in case anyone wishes to do similar, your B2601 valve is on the right side, right above your HST filter and above the linkage. It is the front most and lower most item in the loader valve block and if you observe the photo you will see that it is very easy to locate and get to.

So while you will not change a baby B into a skid loader doing this.... you can make it work much better! There is plenty of pressure for you to tap into. As always, do so at your own risk and of your own accord. If you kill yourself or bust your machine in half, do not call me.

 

[Xfaxman]

My buddy at work has a 2018 Kubota B2601 and he was telling me that he is unhappy with the weak loader and general poor performance of the loader hydraulics. He was saying that he is considering trading it for a B2650 or an L2501 and taking a big loss on his nearly new B2601. So... I offered to crank it up a bit. He was excited to do this.

I did explain that while turning it up, you may possibly shorten the ultimate life span of the cylinder seals and could potentially shorten the life of the hoses.... He agreed that there is a chance, and he really does not care since the B2601 sucks as it came to him and he is very unhappy....

So I started out by gauging the system to see what it looks like at full RPM as it was delivered to him.

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I don't understand why full RPM?

Shouldn't it open the relief at or slightly above Idle?

 

[diesel85]

Sorry, I had to make a jest...

I like the "bust your machine in half"... lol

People hate when I use that wording, but when I see someone else use it, the more hilarious it is.

Now back to reality...

Wouldn't full RPM give the highest pressure?

 

[Rock Crawler]

I don't understand why full RPM?

Shouldn't it open the relief at or slightly above Idle?

Sorry, I had to make a jest...

I like the "bust your machine in half"... lol

People hate when I use that wording, but when I see someone else use it, the more hilarious it is.

Now back to reality...

Wouldn't full RPM give the highest pressure?

The Kubota WSM instructs you to check and set pressure at rated operating RPM, so that is what I do.

I've played with it a bit by reducing the RPM, there really is no change by reducing until you get to idle... My opinion based on the gauges is that RPM changes flow rate, but not pressure once your just a few hundred RPM above an idle. But... For whatever reason.... The work shop manual says to do it this way, so I blindly follow it.

 

[Xfaxman]

The Kubota WSM instructs you to check and set pressure at rated operating RPM, so that is what I do.

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Well that is logical, but rated RPM is not full RPM.

This is what I have always believed, "Rated Power is the maximum power (hp or kW) the engine can produce. Rated RPM is the engine rpm where this peak power occurs."

All of the many machines that I have owned now and in the past would open the relief at idle.

 

[Rock Crawler]

Semantics, when I said full RPM I meant full operating RPM or 540 PTO speed as indicated on the dash.

 

[RickB]

The logic behind testing at rated or full RPM is to ensure the relief valve is capable of discharging 100% of the pump flow while maintaining a safe maximum system pressure.

 

[GreenMtns]

Thanks Rock Crawler Thank is exactly the info I needed. My pressure at operating RPM is 1825 psi. I little too low. Or much too low.

Al

 

[Tractor Seabee]

I could no believe the difference on my BX raising the pressure to 2000 PSI. The biggest change was the speed of operation of the BH. I now operate the BH at less than 2000 RPM or it operates faster than I can think, especially the swinging boom. I think that is probably why if you ask a dealer shop they will try to discourage you.

Ron

 

[inthestick]

My buddy at work has a 2018 Kubota B2601 and he was telling me that he is unhappy with the weak loader and general poor performance of the loader hydraulics. He was saying that he is considering trading it for a B2650 or an L2501 and taking a big loss on his nearly new B2601. So... I offered to crank it up a bit. He was excited to do this.

I did explain that while turning it up, you may possibly shorten the ultimate life span of the cylinder seals and could potentially shorten the life of the hoses.... He agreed that there is a chance, and he really does not care since the B2601 sucks as it came to him and he is very unhappy....

So I started out by gauging the system to see what it looks like at full RPM as it was delivered to him. The goal was to get it up 500 PSI over the starting point. So we attached the BXPANDED.com gauge to the lowest of the 4 loader quick disconnects, this is the line that sees pressure when you pull the lever straight back at yourself to raise the loader boom up into the air. The starting pressure was right at around 1960 PSIG.

So we pulled the pressure relief valve cap and pulled the coil spring out of the cap, inserted a Kubota 4 mil shim into the cap and replaced the spring, then put it back and re-tested. With 1 4 mil shim we got to 2100 PSIG.

We pulled the gauge and he went out to dig into his pile of gravel, he said that it was barely perceptible as being better.... He wanted more. Okay. We really only came up 150 PSI or so....

So back in and put the gauge on, pull the cap, put a second 4 mil shim under the spring (shim goes into the cap, then spring into cap and against the shims) and put it back on, ran it up and pulled a pressure reading. Now we are seeing 2350 PSIG. He ran back out to test and said that this made a noticeable change, and one that he liked.... a lot! So for now we stopped here with 8 mil of total shim and right at 400 PSI increase.

I have attached photos in case anyone wishes to do similar, your B2601 valve is on the right side, right above your HST filter and above the linkage. It is the front most and lower most item in the loader valve block and if you observe the photo you will see that it is very easy to locate and get to.

So while you will not change a baby B into a skid loader doing this.... you can make it work much better! There is plenty of pressure for you to tap into. As always, do so at your own risk and of your own accord. If you kill yourself or bust your machine in half, do not call me.

First off, Thank you for the info!

Now has your buddy seen any side affects of this now since it has been 7 months? I just checked mine, it was right at 2k PSI just above idle and at 2100rpms, pretty much no difference in PSI. So i put in a 4mil shim (From factory it had 3 shims it in already, super thin and what appears to be two .5mil shims and now my .40 mil shim total of 4 shims) and it raised it to 2250. The main reason I did this is it seems like my lifting power has degraded some since new or more noticeable when warm, will monitor it for a few weeks and see.

Next question, has anyone seen the similar issue with there 3rd function valve getting weaker? My grapple seems to have issues staying clamped tightly closed on items (small logs) I know its not a huge machine but when you pick up a log it just slips right back out, I have tried bleeding it by cycle open close many times but it just seems like if you close it hard you can open it slightly even by hand. FYI it is the Landpride 2 cylinder version grapple I can get the part number if it matters.

Thanks,