B26 Repairs

[SamWalton]

We have had our B26 for two years and have only 200 hours of use. We purchased it to prevent the need to contract out many of the tasks related to the development of our land and home build. We had problems with the loader cylinders leaking and a backhoe stabilizer bleeding (scored cylinder) off too quickly at 60 hours. The dealer repaired all quickly and I changed all fluids and filter at this time. Since our warranty only had a few more weeks I brought it in to have them check it out because I felt the performance was somewhat weaker.
We have had the backhoe off a few times and got air in the lines but I was told this should migrate out. I also noticed rear stabilizers would no longer lift the tractor at the lowest throttle position (1000RPMS). After using the backhoe for many hours I thought it was getting weaker and slower.
I addition, a few observation I have made were the four point backhoe mounting has gotten somewhat looser, The paint has chip off and because of this loss of material the backhoe has a slight nock when stress is applied during use.
My dealer's service technician called and said the pressure was good but the flow measured low. Later he told me he was measuring at the wrong location and the first flow meter was bad. After the second day he got the owner involved because of his lack of experience. I spoke with the owner and he said there was no problem with my tractor. During the service the technician installed new hydraulic connectors to the backhoe. He also replaced a leaky hydraulic line to one of the stabilizers and tightened a connection that was leaking since delivery. They did all this for a $120 or an hour and a half of service time. The owner said the brought a new B26 in to the shop and tested both tractors for stabilizers ability to lift at idle. This is the part that bothers me; they set my idle up to a higher position (maybe 1200RPMS) and said it matches the new B26. I am not sure what the low idle specification is? If anyone knows please let me know? I am not sure but I think it use to lift at 1000RPMS. I guess it's time to purchase the shop manual. Does anyone think they may have turned the idle up to avoid finding the problem? I was worried the hydraulic pump may have been damaged because of the medal shaving in the hydraulic fluid because of the previously scored cylinder. Anyway please provide some opinions. Thanks and have a merry Christmas and a happy New Year

 

[ChuckinNH]

Merry Christmas Sam,

I can't answer to all your comments because I've never had a tractor like yours. I did own a little BX22 for a few years though, and did experience some of the things you mentioned. My backhoe also felt weaker, and slower at the end of my owning it. At first I put it down to being more experienced, but then I became convinced that it actually was weaker, and slower. The only thing that I could think of at the time was that I had done many jobs that I really needed a bigger tractor for, and I had maxed it out to the pressure relief valves more than I should have perhaps. My guess was that although the pressure seemed ok, and the fluid flow seemed OK, perhaps I had worn those relief valves, and they were opening earlier, or not completely closing............ OK, you hydraulics guys can stop laughing now! Anyway Sam, I do believe you have an issue, and I hope you keep us posted as you resolve it. By the way, I think my B2620 has the same engine as yours, and it idles below 1200 rpm........... about 1000 I think.

 

[art]

To operate backhoe's properly you should nt be operating them at an idle. This will cause cavitation in the pumps or otherwise known as air bubbles which will score the pumps and reduce the performance levels.

I'd say that with the low hours that that probably hasn't happened yet although I'd change the way you are operating it.

The proper way should be with a minimum of 1/2 throttle to 3/4ths depending on the chore at hand.

What you might be seeing with everything is that it is just getting seated in. From the paint coming off the four point hoe attaching to the use of the stabilizers. With running equipment and a host of other things that I didn't really know how to use or how much something might do I have often found that once I got used to the machine, I still could use more!

 

[EE_Bota]

Merry Christmas Sam,
OK, you hydraulics guys can stop laughing now!

In my experience, hydraulic guys NEVER laugh. It comes from long days of needing to have X-Ray vision due to the lack of test points.

I am not a hydraulics guy. I do play one at work, though, with a inborn willingness to hand it off to anyone else who will utter a single word related to hydraulics. TAG! You're it!

Ultimate force applied by your cylinder has to do with PRESSURE. Ultimate speed of your cylinder has to do with FLOW. Sloppiness of connection points and attachments results in freedom that must be taken up in both directions, therefore some hydraulic work that once resulted in productive work may now be going for unproductive work such as repeatedly taking up slop in the linkages.

It is possible for a worn pump to make pressure without making it's rated flow, but in my experience in a factory running 24x7*, it will not do it for LONG.
Such a pump will continue to degrade, and ultimately fail to make rated pressure.

In hydraulics, I wind up touching the equipment in lots of places looking for heat. All hydraulic power that is not used for productive work produces heat, and if you find the heat, you have found the internal leak. A fixed displacement pump will produce its flow at pressure, or it will get hot.

Some Kubota's (perhaps all) make an early grab for hydraulic flow for the steering, and only after that demand is met will there be power available for other things. It is possible your power steering is demanding a bit more leakage flow than when new.

*This is not meant to add impact to my statements, rather, it implies that once the internal leakage gets out of hand, our factory pumps will skid down the road to ruin much more quickly than your tractor pump.

 

[SamWalton]

To operate backhoe's properly you should nt be operating them at an idle. This will cause cavitation in the pumps or otherwise known as air bubbles which will score the pumps and reduce the performance levels.

I'd say that with the low hours that that probably hasn't happened yet although I'd change the way you are operating it.

The proper way should be with a minimum of 1/2 throttle to 3/4ths depending on the chore at hand.

What you might be seeing with everything is that it is just getting seated in. From the paint coming off the four point hoe attaching to the use of the stabilizers. With running equipment and a host of other things that I didn't really know how to use or how much something might do I have often found that once I got used to the machine, I still could use more!

I don't operated at idle, but Kubota claims the stabilizers can be deployed at idle and this was true but now the dealer bumped up the RPMs since my tractor would no longer lift at idle.

 

[ChuckinNH]

I was just on my B2620, and the idle speed is 1000 rpm as I thought.

 

[Barrys_Toys]

Merry Christmas Sam,

Sam, since your stabiliziers lifted the tractor before, they should do so now! Either the cylinder has an internal leak or there is not enough pressure to the cylinder (ie, check the pressure relief valve). Another possibility is the control valve for that cylinder is bypassing fluid. With open circuit hydraulics the relief valve pressure means that pressure will be available through the system, unless there is a blockage or leakage.

When you hooked up the backhoe lines, did you introduce any dirt into the system?

I have the B26 Shop Manual, but so far have not found the engine rpm setting.

The B26 Shop Manual is Kubota 9Y121-00040, $61.42 from Messiks.

The engine section of the Shop Manual refers to Workshop Manual DIESEL ENGINE MECHANISM (Kubota # 9Y021-01874) which I was unaware of. I bought my B26TLB in July 2008 and purchased the shop and parts manuals at the same time.

If you get the shop manual, I would recommend the parts manuals as well.

Illustrated Parts List Manuals
Model B26 Tractor ----------- # 97898-23430
Model TL500 Front Loader - # 97898-31610
Model BT820 Backhoe ------ # 97898-31620

The Parts Manuals are often more useful as they show how things go together.

Good luck,
Barry

 

[SamWalton]

Merry Christmas Sam,

Sam, since your stabiliziers lifted the tractor before, they should do so now! Either the cylinder has an internal leak or there is not enough pressure to the cylinder (ie, check the pressure relief valve). Another possibility is the control valve for that cylinder is bypassing fluid. With open circuit hydraulics the relief valve pressure means that pressure will be available through the system, unless there is a blockage or leakage.

When you hooked up the backhoe lines, did you introduce any dirt into the system?

I have the B26 Shop Manual, but so far have not found the engine rpm setting.

The B26 Shop Manual is Kubota 9Y121-00040, $61.42 from Messiks.

The engine section of the Shop Manual refers to Workshop Manual DIESEL ENGINE MECHANISM (Kubota # 9Y021-01874) which I was unaware of. I bought my B26TLB in July 2008 and purchased the shop and parts manuals at the same time.

If you get the shop manual, I would recommend the parts manuals as well.

Illustrated Parts List Manuals
Model B26 Tractor ----------- # 97898-23430
Model TL500 Front Loader - # 97898-31610
Model BT820 Backhoe ------ # 97898-31620

The Parts Manuals are often more useful as they show how things go together.

Good luck,
Barry

Barry,
I am sure My B26 backhoe stabilizers lifted the tractor at the lowest idle from purchase to an undetermined time. I am guessing it was 1000 RPS. Why would the dealer fail to find the problem and just turn the idle up to 1350? and install some parts with no charge? My warranty will be over on the December 31st and maybe they have some other motive like they may be required to cover the cost of something they did wrong. This is the second service the first was a warranty repair and this they claim that no problem was found. Maybe expensive pars are marginal and the Kubota pressure and flow specification is relaxed enough they can get away with saying this is no problem? Their mechanic had the wheel off and measured pressure in multiple places and had the valve bodies and cylinders apart.

I always take great care when reconnecting the hydraulic lines by spraying them with WD40 to remove all dirt and wipe with clean cloth and bleeding some hydraulic fluid by mating the connector a few times and wiping with clean cloth again before a final mating.

I am quoting the Kubota Brochure "Increased Stabilizer Power
We've increased the stabilizer lift capacity to give you greater control on any terrain. The improved capacity results in better balance, which reduces
unwanted settling. It also means more strength-rear tire lift is possible even while the tractor is idling.

If it is not too much trouble, I would ask you B26 owners to test for the rear tire lift at lowest throttle position and note the RPM. Please let me know the results? Thanks!

If the dealer has handled this wrong? What is my next move? Kubota doesn't have a technical support line or do they?

I have downloaded all the parts manuals but need to purchase the shop manual PDF. It sounds like the Idle may be in this other engine manual.
Thanks for all the help so far
Sam

 

[nspec]

I've got a b2630, which I believe to be identical to the B26. Perhaps a different pump? That is beyond me, but in any case, with the bh75 hoe, stabilizers lift machine at idle which is about 750-800 rpms - no problem. I've got 90 hrs on my machine, about half of it is very heavy backhoe work - stumps, and very large rocks.

 

[jlrsn]

Sam,
I'm going to make the following as simple as possible and I don't have any B26 manuals to refer to. The B26 Hydraulic Pump is a Gear Type Pump which is one of the most common and dependable pumps used on tractors and aircraft as well as anything else that needs to make liquid pressure. Normally the design of a Gear Type Pump is such that it produces more pressure (PSI) than required to allow for low RPM. The pressure is reduced to operating pressure by an adjustable relief valve and the flow is probably set by calibrated orifices subject to the operating pressure. Both can be accurately measured with quality gauges used properly. The PSI can be confirmed by plugging into a port of the system being tested but normally the flow can only be measured by an inline flow gauge.

I don't know how many hydraulic pumps are used on a B26 but from the online specs I know that the B26 Hydraulic Pump produces 11.2 GPM of which 7.0 GPM is for the loader/backhoe/3-point hitch, 4.2 GPM is for backhoe boom swing, 6.2GPM for power steering per the online specs. I want to say that there are at least two hydraulic pumps with one for the power steering. My L39 has 3 pumps. I also know that the B26 Hydraulic System Relief Valve is supposed to be set to 420.6 PSI which is a low pressure system. I've found that most dealers don't have the equipment or know-how to accurately measure hydraulic flow. In reading the B26 advertisements I read that the B26 Rear Stabilizers are supposed to lift the tractor at idle speed. If it did when new it still should unless the system pressure is adjusted too low or the internal O-ring seals of the Stabilizers are leaking internally which is usually the reason for a leak-down!

With over 50 years of working with hydraulic systems I find that most mechanics don't know how to properly prepare a Lip, Chevron, or Garlock Type Seal properly and that is why some owners have repeated leaks. I have never had a Lip, Chevron, or Garlock Type Seal leak before TBO (Time Before Overhaul) after I've replaced them and I've replaced probably thousands since the 50s.

I seriously doubt that your Hydraulic Gear Pump has been damaged by any shavings and gear pumps can usually last thousands of hours (If not made from powdered metal). Rarely will cavitation damage a gear type pump as there is usually enough residual fluid in the pump to lubricate the gears.

Ask your dealer for the exact readings of PSI and GPM and to show you the gauges he used to measure the pressure and flow. I don't think he measured the flow. Keep us informed.

Good luck,
Jim

 

[powerstroke444e]

Sam
I have a B26 and always thought the idle was a little high, it runs a little over of 1,100 rpm. It does lift the rear off the ground @ idle. I blew out both front cylinders @ about 50hrs and had them replaced, and had a hydraulic line leak from rubing on loader. On the machine I ussually run it wide open all the time.
I would guess we have had it stuck more times than I can count, one time we winched it to the spot that need pipe fixed and winched it out. I have overloaded the hoe and loader but overall I would say that the things I have broke are to be expected but that it has done more than I would have ever expected of it.
On the 4pt hook up my has finally got loose enough to hook with out a hammer.
I have spent last 12hrs making a grapple for the front of mine and really wish I just bought one as there is a lot more welding than I thought in building a grapple.
Enjoy reading your house build, have a great New Year.

 

[SamWalton]

I called Kubota's customer satisfaction hotline at 310-370-3370 ext 1918 or 1959 and also spoke with the warranty office at ext 1950. They put me in touch with the local service representative in Fort Worth Tx and I told him about lack of proper service and he has David Dearmond setup to trouble shoot my tractor at my dealer Date TBD 817-571-0900 ext 4911. The service representative can extend the warranty to cover problems that should have been found in my last service.

Other good phone number to keep in mind

Kubota Tractor Corporation
3401 Del Amo Blvd., Torrance, CA 90503, U.S.A.
310-370-3370
310-370-2370
Kubota Credit Corporation U.S.A.
3401 Del Amo Blvd., Torrance, CA 90503, U.S.A.
310-370-3370
310-370-2370
Kubota Manufacturing of America Corporation
Gainesville Industrial Park North, 2715 Ramsey Road,
Gainesville, GA 30501, U.S.A.
770-532-0038
770-532-9057

 

[jlrsn]

Sam,
You don't play around! The contact numbers that you received are excellent to have!!

The first thing I'd do is to accurately measure the Hydraulic System Pressure with a Calibrated Master Pressure Gage at the correct Idle RPM and adjust the Hydraulic System Pressure Relief Valve to 420.6 PSI.

I seriously believe that with the required System Pressure at Idle RPM all your flows will be where they belong. The reason I state that is that to achieve the advertised flows through Calibrated Orifices in GPM you need 420.6 PSI at Idle RPM. You DO NOT just raise the RPM!!! When you are running your Engine at any other speed above Idle RPM the Hydraulic System Pressure Relief Valve will maintain 420.6 PSI. I don't believe that the Hydraulic Flow of your Kubota Tractor is adjustable without changing the size of the Orifices.

As before, I don't have the Kubota B26 Manual but Hydraulics was one of my specialties of many and I've designed Hydraulic Systems, taught Hydraulics, and traveled Internationally as an Aviation Consultant throughout the Americas, Europe, Russia (Including throughout Siberia), Asia, and Africa. I was also an Independent FAA DME (Designated Mechanic Examiner) for both Airframe and Powerplant giving the A&P Oral and Practical Exams for many years before I retired.
Good luck to you,
Jim

 

[SamWalton]

I know a bit about Hydraulics systems I was an electrical/electronics production engineer in the flight simulation industry with Loral Quintron and Simtec, Inc.
I thought I would see what kind of service my dealership could provide and also get any warranty coverage that may be due to me. Also I know little about our B26 but plan to learn more by handling most future repairs.

Thanks for all the help
Sam

 

[jlrsn]

Hi Sam,
I seriously doubt that you need to buy a Flow Meter as I doubt that the Kubota Hydraulic Flows are adjustable. If the Hydraulic Pressure is maintained at 420.6 PSI by the Hydraulic System Pressure Relief Valve only a given amount of Flow (GPM) will pass through the orifice per minute. The Hydraulic System Pressure Relief Valve must first be adjusted to the 420.6 PSI at the proper Idle RPM. To set the Hydraulic System Pressure Relief Valve a Calibrated Master Pressure Gauge, or at least a Calibrated Pressure Gauge must be used, not the off the shelf hardware variety commonly found at dealer service departments.

By chance did you ask the dealer what pressure showed at the proper lower Idle RPM before he bumped up the RPM which of course increased the pressure until the relief valve kicked in.

I followed the building of your house and now with the latest pics and Bio info I almost feel that I know you.

Please keep us informed,
Jim

 

[lhansman]

I purchased a B26 in October with 196 hours on it and it had evidence of a hydraulic leak at the back end as well. The dealer told me that almost a year ago they had replaced a rear stabilizer hose that had blown on the previous owner. I thought the oil looked a little too fresh to be that old but since I was buying the B26 with a 12 month, 200 hour warranty I wasn't worried.

Sure enough when I got the machine home after my first Saturday of using the hoe there was a pool of oil on the garage floor under the backhoe hydraulics the next morning. It was a slow leak and I had some weekend work I wanted to get done before winter set in so it was a few weeks before I returned the machine to the dealer. They kept the machine for almost a week and determined that the problem was in the hydraulic valves for the backhoe.

Due to the expense of the parts involved they actually asked me if they could keep the machine a few additional days so the Kubota rep could have a look before the dealer purchased a bunch of expensive parts. I don't know exactly where the problem was but in the end the dealer told me that they had to disassemble the valve body and repair/replace an O-ring that had been improperly installed at the factory.

As far as performance goes, I notice the B26 backhoe operation feels slower than my old B21 but I just assumed this was due to the precision of the inching valves which are a real treat after the learning curve I had to go through to get smooth with the B21 hoe. I definitely like the added power of the B26 though and certainly would not go back to the B21.

As far as idle and stabilizer lift, I know my machine idles under 1000rpm and at idle the stabilizers lift the B26 off the ground wthout any problem. Your idle speed should definitely not be 1200rpm or higher.

With respect to air in the hydraulic system from disconnecting the backhoe, I remember reading in the owners manual that if you want to bleed air from the hydraulic system from changing a hose or implement, Kubota suggests turning the power steering from left to right a few times to bleed the hydraulic system.

One other tip for B26 owners. When I first saw my used B26 on the dealer lot it was missing the amber lenses on one of the hazard lights on the ROPS. I had the dealer replace them with new ones and then was moving through a couple of tight pine trees on my property and one of the new lenses landed in my lap and when I turned around the other was on the ground. When I looked at them it turns out they just pop on and I guess one of the pine branches rubbed or hit the lenses the right way to pop them both off. I have since taken a long plastic zip tie and wrapped it around the left and right sets of lenses to make sure they don't disappear again.

 

[tandttravis]

Sam, I have 325 hours on my B-26 that I purchased in December 06. My idle is just under 1000 rpm, and my stabilizers will lift the machine of the ground at idle, even with loaded tires. I have had very few problems with my machine, and none required bringing back to the dealer. As far as the backhoe, it does seem slow, but the power seems consistentand I have quite a few hours on the backhoe. I have been very happy with my machine, hope you get your issues resolved, best of luck.

 

[RichT]

Sam, sorry to hear of your problems. My 26 has a little over 100hrs. As you know the idle speed should be slightly below 1000rpm and at idle the stabs will lift the rear effortlessly.

Its a little discomforting to think the dealer might be trying to mask an issue with the tractor. Either way, Kubota should make it right.

Keep us posted.

 

[SamWalton]

Sam, sorry to hear of your problems. My 26 has a little over 100hrs. As you know the idle speed should be slightly below 1000rpm and at idle the stabs will lift the rear effortlessly.

Its a little discomforting to think the dealer might be trying to mask an issue with the tractor. Either way, Kubota should make it right.

Keep us posted.

I brought our B26 back to Perrin & Gray Tractor Fort Smith, AR today. We hope the local Kubota Rep David Dearmond will correct this problem. I will keep you all posted on our experience.

 

[lakeside]

I just bought a B26 in the spring so I'm be very interested in what you find out.

BTW: I had a hose leak seven working hours after I bought the machine, I wasn"t a happy camper.

Although used, the dealer Carriere in Alfred, Ontario, sent a tech 60 miles one way to fix it.

It turns out a 2" piece of gravel had lodged between the skid plate and the hose going to the backhoe. Over time the rock had worn down the hose. Apparently Kubota ships tractors with 2 ply hoses and my dealer at least replaces damaged hoses with four ply. In any event, B26 owners may want to keep and eye out for debris caught on the skid plate.