B 26 backhoe running slower and slower

[westcliffe01]

Just to comment on a similar problem I had with my Superstav (badge engineered and called a Bobcat B200)

When I bought the unit it had been a rental, has 1300 hours on it. The backhoe specifically had been used most, some of the pins were worn and some of the bucket teeth were loose, the hoses leaked and the renters had torn up the 1/8" thick guards over the stabilizer cylinders using the bucket teeth....

Anyway, I started doing maintenance on it a bit at a time (bought in 2009 and I have put 200 hours on it since, so it is not in use every day). Last year I replaced all the hoses on the backhoe and lost a lot of fluid in the process and decided I needed to replace all the hydraulic fluid and the pickup screen and filters in the tank. I did not have a spec on the oil and got general purpose hydrostatic fluid at TSC.

When operating the machine without actually "working" everything appeared normal. But the first time I had to do any serious digging with the hoe I was struck with how feeble it was. As summer wore on I did a lot of work with the loader and I noticed that as the machine heated up, the loader became increasingly feeble too.

After a lot of digging and checking I finally concluded that the biggest common factor was the 15 gal of new oil I put in it. Checking into that oil, I discovered that the generic hydrostatic fluid is SAE10 viscosity. I read through every page of the factory manual for the machine and finally right at the back discovered that the oil used in the system was a multigrade 15-40 or 20-50 in other words basically engine oil. Holy moley..

So after that lesson, I drained the tank again (an expensive flush) and gave the fresh oil to the farmer for one of his ag tractors from the 1940's.. Then filled it with 15-40 multigrade. Obviously some of the lighter oil was still held in the various cylinders on the machine, but the performance improved immediately.

The hydraulic system on my machine happens to be laid out for 5000psi working pressure, not like some ag systems. So this system really needs heavier oil or else the internal leakage in the pumps is excessive. I will probably have to do another partial drain this year when I work on replacing some of the balance of the hydraulic hoses that seem to be at the end of their useful life (it seems working at 5000 psi if not conducive to long life) so that should help get rid of a bit more of the lighter oil that was left in the system.

This may not be your issue, but it had me really concerned for quite a while. After correcting things, both the hoe and loader are capable of lifting the machine clear off the ground, so it was not a hardware issue.

 

[J_J]

westcliffe01 ,

Can you possibly take a relief valve reading. Just curious if the hyd system can sustain pressure over 3000 psi.

What is the pressure rating on the hoses on your machine?

 

[Gary Fowler]

westcliffe01 ,

Can you possibly take a relief valve reading. Just curious if the hyd system can sustain pressure over 3000 psi.

What is the pressure rating on the hoses on your machine?

I haven't checked for pressure gauges other than local shops and no one carries them, even the Kubota dealer didn't carry any. I suppose I could go to the BXpanded website and pay triple for them.
A quick question on the relief valve, If I get a gauge and a flowmeter to do the work myself, does anyone have a set of instructions on 1) how to remove and set the PRV for the right pressure, everything is screwed in upside down and I don't know what all is going to fall out when I unscrew the valve (2 How to set up the flow meter with pressure gauge to see the GPM output.
If you take off the PRV will the hydraulic lines loose pressure or do the valves hold everything. One of the reasons I am hesitant to work on it is that I don't have any thing to block up the tractor with and it would have to be up pretty high to be able to get underneath it to get to the PRV. I have some HF jack stands but I don't know if I would trust my live to them to hold.

 

[Gary Fowler]

If I were you I'd pay close attention to what J J said about how the controls may be tied to a certain hose orientation from the factory. And until you commit to having someone test the flow and relief settings you'll never solve this problem. If you're possibly doing damage to your pump now by running the hoe at high fluid temps and possibly restricted flow, (clogged screen?), you may end up killing the pump and incurring big expenses in the long run.
Forget the first dealer- they ignored what you asked for and billed you to smash rocks on their lot for an hour?! AND they re-oriented your lines to how they were supposed to be from the factory- which now may make sense based on what J J said.
If it were mine I'd find a dealer or local hydraulic shop equipped and knowledgeable about tractor hoes and pay them to do the tests, NOW, not later, and figure out what is wrong. Short $ now- or long $ later.
This problem will not solve itself. Your hoe is trying to tell you something- you need to listen to it and fix it:thumbsup::2cents:

First off, it has been set this way (excavator style for levers) since new and it worked fine for first 200 hours or so. I don't really see how swapping the hoses from SAE setup to ISO set up would damage anything as one runs the boom and other the dipper so not much difference in pressures and flow requirements, certainly shouldn't be any restrictors in those lines, perhaps it should have some in the swing as it moves a tad too fast for my needs.
I will look to take the machine to the other Kubota dealer in HOPE Ark. soon. I just don't relish the idea of loading and hauling it in windy, rainy, snowy conditions and when we have had a few good warm sunny days, I always seem to find other things to do that are more important. March here usually has some nice spring days so I will see what comes. I will of course let everyone know when I get it worked on what the outcome is.

 

[J_J]

A short hose, this 3000 psi hyd gage, and a QD to match your tractor, or a gage screwed into the QD.. About $30.

Surplus Center - 3000 PSI 2.5" LF LM GAUGE

 

[EE_Bota]

I haven't checked for pressure gauges other than local shops and no one carries them, even the Kubota dealer didn't carry any. I suppose I could go to the BXpanded website and pay triple for them.
A quick question on the relief valve, If I get a gauge and a flowmeter to do the work myself, does anyone have a set of instructions on 1) how to remove and set the PRV for the right pressure, everything is screwed in upside down and I don't know what all is going to fall out when I unscrew the valve (2 How to set up the flow meter with pressure gauge to see the GPM output.
If you take off the PRV will the hydraulic lines loose pressure or do the valves hold everything. One of the reasons I am hesitant to work on it is that I don't have any thing to block up the tractor with and it would have to be up pretty high to be able to get underneath it to get to the PRV. I have some HF jack stands but I don't know if I would trust my live to them to hold.

I like my BXPANDED gage. Costs come in all forms.
No one cares where you get a gage, only that you begin to report pressures to the resident experts so that they can help.

 

[Gary Fowler]

Well I ordered the gauge and maybe it will be here in a week or less. Will see how that goes and if I need to do a flow test.
I just used the TLB to dig a hole to bury a calf and it worked ok for that. I think it is just getting weak when the oil gets hot or maybe the oil gets hot because it is by-passing. I will check it when I get the gauge ($16.95 for the gauge and $12.95 to ship)

 

[Jaylegger]

Perhaps this has no bearing on backhoe operations for this particular tractor but is there a chance the 3-point hitch lever is partially engaged?

 

[westcliffe01]

All the hoses and fittings on my machine are 5000psi "working" pressure rated. I had a heck of a time finding the DKOL crimp fittings (and the proper hose for them) but eventually I found a supplier in California that had it and a chart for the crimp diameters for all the different size fittings and were very reasonably priced.

There are many things about these european machines which are not the same as the equipment we are familiar with, and the oil just happened to be one of them.

westcliffe01 ,

Can you possibly take a relief valve reading. Just curious if the hyd system can sustain pressure over 3000 psi.

What is the pressure rating on the hoses on your machine?

 

[Coyote machine]

First off, it has been set this way (excavator style for levers) since new and it worked fine for first 200 hours or so. I don't really see how swapping the hoses from SAE setup to ISO set up would damage anything as one runs the boom and other the dipper so not much difference in pressures and flow requirements, certainly shouldn't be any restrictors in those lines, perhaps it should have some in the swing as it moves a tad too fast for my needs.
I will look to take the machine to the other Kubota dealer in HOPE Ark. soon. I just don't relish the idea of loading and hauling it in windy, rainy, snowy conditions and when we have had a few good warm sunny days, I always seem to find other things to do that are more important. March here usually has some nice spring days so I will see what comes. I will of course let everyone know when I get it worked on what the outcome is.

I'm not looking to argue with you or p@#s you off; merely seeking to light the fire that gets you to take it over to the other dealer and get it checked out. You state that it worked fine for 200 hours- so what happened then? Did something change?
Does the possibility that the hoses were installed other than factory design for your hoe present any credibility to you regarding the possibility that this could have caused the current problem over the 200+ hour timeframe?
If it were me, I'd certainly want to check this line of thinking out with your next dealer, at least to finally rule it out as a possible cause. You don't really have anything else, other than a possible flow restriction/over/under/pressure setting to consider do you?

 

[Tractor Seabee]

Gary,

If you are going to work on your tractor yourself (I highly reccomend) the shop manual is a must have. Best $80 I have spent, has saved me thousands. Up here shop labor is $125/hr and I have been disappointed by their attitude, slow service, and prices. Its over 50 Miles to the good dealer shop. On my BX 25 the relief valve is on the rear of the trans case, easy to get to and no it won't spray you when you unscrew the cap to get at the spring. Springs can be iffy, and they break for no reason. May well be your problem. I just raised my pressure to 2000#, huge differance in performance. The little shims are cheap even at the dealer. Less than $1 for what I did in 10 minutes. Yes I have a gauge, the Surplus Center one, a steel tee and two QDs (M & F). The QDs (they are Parker) I got at the local Hyd Shop) as the SC ones do not match. Less than $40.

Ron

Ron

 

[Gary Fowler]

My 3000 PSI gauge came into and I hooked it up, got 2200 PSI at idle. Reving up to 2000 rpm didn't raise the pressure any, still steady at 2200. Now to find out what the pressure should be.
EDIT: Just read the manual for both backhoe and tractor and only pressure mentioned is max pressure on the loader which is 2402 PSI. Therefore it looks like my pressures are below the max but still should be good. I'm not going to try to shim up to get the additional 200 PSI. The flow may be slowing down for some reason, maybe a early fluid change(400 hour required, but only got about 220) to SUDT2 will help.
Maybe the pressure has reduced somewhat since I don't know what it was originally set at, it could have been set higher than recommended also. I think I will just live with it like it is for now, if something else requires repair at a shop, I will have them check the flow and set the pressure to max.
The only thing I haven't been able to check is that screen going into the reservoir that Carl told me his B21 had, but I don't know if the B26 has this as it doesn't look the same. Got to go to Kubota dealer for an air filter and motor oil filter so I can ask them. MAYBE they have a B26 maintenance manual.

 

[Carl Bert]

My 3000 PSI gauge came into and I hooked it up, got 2200 PSI at idle. Reving up to 2000 rpm didn't raise the pressure any, still steady at 2200. Now to find out what the pressure should be.

If you can't find someone with a shop manual to give you the correct specs, just tell me where to get a gauge (I need one anyway), I'd be happy to do pressure tests along with you and tell you what readings I get. I would need specific directions though, I'm not too knowledgable when it comes to hydraulics. Although there is always the possibility that my tractor also isn't pumping at full potential, but I doubt that. Ok let me know if I can help.

 

[Gary Fowler]

A short hose, this 3000 psi hyd gage, and a QD to match your tractor, or a gage screwed into the QD.. About $30.

Surplus Center - 3000 PSI 2.5" LF LM GAUGE

This is where I got mine thanks to JJ. It took about 4 days from time I ordered it. The gauge was only $16 but shipping and tax boosts it up to just shy of $30.
At least now I know what the pressure is but maybe not what it was when I got it.
The way I checked the pressure (which may or may not be the right way), was I took off the stabilizer hose connection which happened to be exact fit for the gauge, tightened it up, cranked up the tractor at idle and hit the stabilizer control lever slowly , the gauge slowly came up to 2200 but went back to zero when I released the lever which to me seemed to mean that the stabilizer valve has some leak by. I next revved the engine to 2000 and did another check, same pressure. Removed the gauge, hooked the hose back on the stabilizer and cycled it a couple of time to remove the air.
The reason I did it this way was first of all I didn't need to make a trip to get any QA connections and second, in order to get to the supply line, I would have had to disconnect the back hoe which I really didn't want to do.

 

[Carl Bert]

This is where I got mine thanks to JJ. It took about 4 days from time I ordered it. The gauge was only $16 but shipping and tax boosts it up to just shy of $30.
At least now I know what the pressure is but maybe not what it was when I got it.
The way I checked the pressure (which may or may not be the right way), was I took off the stabilizer hose connection which happened to be exact fit for the gauge, tightened it up, cranked up the tractor at idle and hit the stabilizer control lever slowly , the gauge slowly came up to 2200 but went back to zero when I released the lever which to me seemed to mean that the stabilizer valve has some leak by. I next revved the engine to 2000 and did another check, same pressure. Removed the gauge, hooked the hose back on the stabilizer and cycled it a couple of time to remove the air.

Correct me if I'm wrong, but the way I understand it is, the hydraulic system is in a continuous loop, so doesn't this gauge need to have a "T" on it with a male and female end, so it can be connected within the loop? So my question is, do I need to order a "T" connector along with the gauge?

 

[woody]

Gary, glad you got you a gauge from what I understand Kubota sets the pressure at the low end of the scale. When I raised mine it was only about 250 psi and I could tell a real difference. But what I did not do was to make sure the oil was hot and I can tell a difference now when I run it along time. Good luck

 

[Coyote machine]

My 3000 PSI gauge came into and I hooked it up, got 2200 PSI at idle. Reving up to 2000 rpm didn't raise the pressure any, still steady at 2200. Now to find out what the pressure should be.
EDIT: Just read the manual for both backhoe and tractor and only pressure mentioned is max pressure on the loader which is 2402 PSI. Therefore it looks like my pressures are below the max but still should be good. I'm not going to try to shim up to get the additional 200 PSI. The flow may be slowing down for some reason, maybe a early fluid change(400 hour required, but only got about 220) to SUDT2 will help.
Maybe the pressure has reduced somewhat since I don't know what it was originally set at, it could have been set higher than recommended also. I think I will just live with it like it is for now, if something else requires repair at a shop, I will have them check the flow and set the pressure to max.
The only thing I haven't been able to check is that screen going into the reservoir that Carl told me his B21 had, but I don't know if the B26 has this as it doesn't look the same. Got to go to Kubota dealer for an air filter and motor oil filter so I can ask them. MAYBE they have a B26 maintenance manual.

FWIW, Here's a link I found to an older thread talking about shimming for max or over max psi of the relief valve- (I don't know Kubotas very well so it may be an earlier model or not even your model, but if it helps....) http://www.tractorbynet.com/forums/customization/134652-bx-christmas-present.html hope it sheds some light. I just did a search on Google for bx PRV valve max pressure, etc.

 

[Gary Fowler]

Gary, glad you got you a gauge from what I understand Kubota sets the pressure at the low end of the scale. When I raised mine it was only about 250 psi and I could tell a real difference. But what I did not do was to make sure the oil was hot and I can tell a difference now when I run it along time. Good luck

So, does the oil pressure drop considerably when it gets hot like the oil pressure on a car? I didn't think of that and the oil was 40F which was ambient temp when I checked it. I just started it up and within seconds checked the pressure at idle which is 1100-1200 RPM on this TLB.
Has anyone checked their pressures cold then again when hot and noted any difference?

 

[Tractor Seabee]

Carl raised the important point. You are measuring dead end pressure not operating pressure. You need a tee and QCs to insert in either the pressure or the PB line to/from the BH. That way you can see any changes when operating cylinders (important to trouble shooting your problem). The gauge will not interfere in operation that way also. That is the true operating pressure. SC does not have the Parker QC Kubota uses. Get the number off yours and go to your hyd store for a steel tee and the QCs. Not familiar w/the BX 26 but my BX 25 factory spec is 1778-1849 psi at 104-122 degrees F and max RPM. I have mine at 2000 now and it made a world of difference. See my eaerlier post.

Ron

 

[Gary Fowler]

Carl raised the important point. You are measuring dead end pressure not operating pressure. You need a tee and QCs to insert in either the pressure or the PB line to/from the BH. That way you can see any changes when operating cylinders (important to trouble shooting your problem). The gauge will not interfere in operation that way also. That is the true operating pressure. SC does not have the Parker QC Kubota uses. Get the number off yours and go to your hyd store for a steel tee and the QCs. Not familiar w/the BX 26 but my BX 25 factory spec is 1778-1849 psi at 104-122 degrees F and max RPM. I have mine at 2000 now and it made a world of difference. See my eaerlier post.

Ron

There is just a small problem with that in that with the hoe attached, you cant get to the couplings, you have to unhook the back hoe, drive forward a foot or more to get to the hoses so I couldn't just stick one inline and see what was happening. The tractor has no other hydraulic outlets on it. I suppose I could unhook the hoe, then put the gauge in between the lines (you unhook from the hoe and loop the supply to the backhoe back into the return. I don't think I would get much pressure showing in the loop as it would just be circulating to an open end so I wouldn't think it would show me any pressure above the resistance. I watched a video of someone checking the flow by doing the same thing, except they had a needle valve to gradually shut down the flow till it dead headed to check the max pressure before the relief valve opened. Flow seems to be based on no load conditions, as the pressure builds flow decreased till 0 at max pressure and dead head. That is what I was concerned with was that the relief valve was set too low. NOW it would be nice to have a flow meter and verify the flow.
Anyone know where to get one of those?