Backhoe B26 hydralics bypassing

[woody]

Hello newbie here with a story to tell. I purchased a used B26 with 38 hours on it and it is a 2009 model. First time operating it (not my first time on a backhoe) I thought the backhoe was weak, very weak so I babied it until I had 50 hours on it to be sure it was not just me. Carried it in for a fifty hour service and explained to the service guy and his boss what I thought. When I got it back they said there was nothing wrong. So I ran it another ten hours and carried it to a different dealer. After a week he calls and tells me nothing wrong with my b26. while I was on the phone he mentioned the Kubota rep was there and I asked him several times to get the rep to look at it within ten minutes the rep told him that there was something wrong and told him to adjust the bypass valve for the backhoe. I got it back and it is better, but it is still not right. When you reach out with the backhoe and try to get some dirt it does not dig, does not move the machine, and does not pull the motor down. Ok enough of my whining what is your advice?

 

[wdchyd]

Welcome to TBN Slywoody:welcome:

Hopefully this site helps you to success at your problem.....

You'll need to find someone with a flow meter w/ load valve.....takes minutes to hook up and seconds to tell if somethings wrong......

Kubota Flow/Load Meter Test - Tractor Videos - Kubota, John Deere, New Holland and More

Here's a test run on my new B2320 with flow meter installed in place of backhoe.....could of been just as easily installed upstream or down stream of BH......Had the BH been installed while doing this test, digging and movement of the machine would be possible to verify good or bad results.....

At least you won't be guessing at pressures and flows, you'll see it in real time......one of the problems with hydraulics is you cannot see pressure and flow internally in hoses and cylinders without guages and test equipment...similar to electrical troubles where voltmeter and amprobe is needed.......

Find someone that has more than just a pressure guage, it'll save you alot of aggravation....:thumbsup:...Then you can fix it or live with it

 

[kennyd]

Find someone that has more than just a pressure guage, it'll save you alot of aggravation....:thumbsup:...Then you can fix it or live with it

I think a simple pressure gauge will help a lot here...and they are cheap ($30) compared to a flow gauge. He can check the PRV (pressure relief valve) with it-and that is what seems like could be set improperly.

 

[woody]

where do I get a pressure guage set up for the Kubota?

 

[kennyd]

where do I get a pressure guage set up for the Kubota?

You can buy 0-3000 PSI gauges at TSC (Tractor Supply) or at the Surplus Center online. You will then need to determine the type and size of the ports that go to the cylinders.

 

[wdchyd]

I think a simple pressure gauge will help a lot here...and they are cheap ($30) compared to a flow gauge. He can check the PRV (pressure relief valve) with it-and that is what seems like could be set improperly.

Very true, but didn't the OP did say that he brought it to two different dealers(one had it for a week)....can't imagine at least one didn't use a pressure guage....

Didn't Akkaman's threads hammer home it needs Pressure and flow to do work???

I've seen lot's of times the hyd pump was right on the edge of NG (according to the guage it's OK) and the pump flow quits at rated pressure.....going into a stall while trying to do work......

Yes it's cheaper but life isn't always cheap to troubleshoot....

If the dealer cannot tell the OP what pressure/flow is putting out, then find another place to bring it......:2cents:

 

[MarkV]

Woody, welcome to the forum. I would think a tractor bought with 38 hours would still be covered by warranty. What were the details of your purchase? That is an unusually low number of hours for a used tractor from a private owner.

I think the guys that recommend a pressure gauge are right. At least then you can verify if the relief valves are set to spec's or the tractor just isn't what you expected. It doesn't sound like you have had enough hours on the tractor with the proper settings to know what it should do yet.

MarkV

 

[J_J]

Have you rechecked all the QD's and is there a return hose to tank from the BH?
There should be no back pressure on that line. Does your FEL work OK. Where is the fluid coming from gong to the BH? Otherwise the routing of the hyd flow. Are the hoses to the BH connected correctly?

Stay on your dealer about the situation, and make him show you how it is working good.

 

[woody]

Mark, the previous owner passed away and I bought it from his wife. I did carry it to two dealers. I also own a Lay-Mor backhoe with a 25 hp Kohlar on it that I have had for about ten years I thought the Kubota should out do the lay-mor but it does not, well at least the backhoe does not. where is the bypass located at on the B26?

 

[woody]

ok after tring out the tractor it still does not perform correctly, called the service man last week and he told me he would get with the rep. I had to go right by the shop today so I stopped in. the service manager could not tell me what my pressures were or at what pressure they bypass all he would say is that they adjusted them to 40PSI above max. I ask had he called the rep and he had not. is this adjustment done by shims or is it an adjustment.

 

[MarkV]

ok after tring out the tractor it still does not perform correctly, called the service man last week and he told me he would get with the rep. I had to go right by the shop today so I stopped in. the service manager could not tell me what my pressures were or at what pressure they bypass all he would say is that they adjusted them to 40PSI above max. I ask had he called the rep and he had not. is this adjustment done by shims or is it an adjustment.

Woody, first I would say the service manager should have easily been able to tell you what Kubota's recommended pressures are. I would hope they have a shop manual that would show them. When you use the term "bypass" it is the pressure relief valve that seems to be kicking in. My understanding is the pressure relief valves are adjusted with shims. The shims are available through Kubota. You need a pressure gauge to see what is what. Do a search on the forum. Several members have documented the process.

Kind of sorry that 2 dealer service centers as well as a company rep haven't figured it out.

MarkV

 

[woody]

Mark, thanks for the advice. the reason I ask that question was I have been reading on here and seen where other tractors were adjusted by shims but when the service man said they adjusted mine I ask him point blank with shims or an adjustment and he said the B26 was an adjustment not shims but that it is not hard to do. made me scratch my head all the way to my truck. been tring to get in touch with Marcus Hecker the Kubota Rep. but no luck
Thanks again for letting me vent.

 

[MarkV]

Well Woody I could be wrong. I have a B21 and although I have never adjusted mine, I have been told by those who have that it was shims. The B26 is a newer model and could have a different system.

MarkV

 

[wdchyd]

Well Woody I could be wrong. I have a B21 and although I have never adjusted mine, I have been told by those who have that it was shims. The B26 is a newer model and could have a different system.

MarkV

You both could be right.....depends on the manufacturer and specs given by the tractor mfg......both do exactly the same where the one with shims does not allow for tampering with......both work the same when adjusted properly......

 

[kennyd]

I believe the "shims" are used on the tractors main PRV on the transmission. They are adjusting (I would assume) the valve on the hoe, and that is probably a jamb nut type PRV.

 

[woody]

does anyone have directions and maybe pics of the prv main and hoe. the lifting on my fel is not what my other backhoe is. if I increase the pressure on it will it make a difference on the hoe.

 

[J_J]

If everything else is good, raising the pressure will increase the force. You should know the upper limit for the BH before adjusting the relief valve. You will need a gage to do this. You might have a leaking valve, or something. Is your tractor supplying the pressure and GPM's for the BH?

 

[woody]

JJ, from what the service manager said (yes). but when I asked him what the numbers were he would only tell me that they set the BH 40psi over max. I am finding some of this info hard to believe.

 

[J_J]

Does he know your tractor psi rating. By setting the BH PRV over max. What max. The main valve/fel valve will then control the relief pressure for the complete system..

Another thing, is how can you set 40 psi over unless you have the pressure to observe.

Essentially what he is referring to is that if the BH PRV is set over the over the limits of the BH, is that the FEL PRV will provide the only pressure and protection for the hyd circuit. . T

 

[woody]

Does he know your tractor psi rating. By setting the BH PRV over max. What max. The main valve/fel valve will then control the relief pressure for the complete system..

Another thing, is how can you set 40 psi over unless you have the pressure to observe.

Essentially what he is referring to is that if the BH PRV is set over the over the limits of the BH, is that the FEL PRV will provide the only pressure and protection for the hyd circuit. . T

like I said I am having trouble understanding this