B26 tlb hydraulic issues

mmargush · Jan 18, 2014

Hello,
First time poster. I've searched with no findings on the same issue I have. My B26 loses it's hydro prime while sitting. Occasionally loses hst while in motion till all the air works out. the problems showed after I did a hydro fluid change with filters. using the gold kubota super udt2 as recommended ..OUCH! I'm wondering could a check valve in the filters have gone bad? or where should I look for an air leak? I've had to replace an oring on the hoe manifold and one on the loader set as well. but an fine after those repairs. Today (30 degrees F) my steering turns fine at idle but as soon as you throttle up it gets tough.... Multiple issues or related?
Any ideas?
thanks in advance!

Gary Fowler · Jan 18, 2014

Sounds like a gasket is leaking on the hydraulic filter. Did you check to see if the old gasket came off with the old filter? If you need to remove the filter, use the old vacuum on the oil filler hole trick to keep the oil from pouring out when you remove the filter. There is a video on TBN on exactly how it is done, but pretty simple, just turn on the vacuum, put the suction hose in the filler hole and let it run while you remove the filter and examine the filter connection. There will be some oil from the filter to run out, but the reservoir should remain drip free.

mmargush · Jan 19, 2014

I haven't had a chance to check it out yet. I'll grab new filters this week and swap. I wondered about the gasket after watching that video of the vacuum trick. I'll report back. Thanks for the idea!

mmargush · Jan 21, 2014

changed the filters last night. everything looked ok. I only bought a gallon to refill teh system with and had troubles with the vacuum trick. I actually had fluid suck into the vacuum and then it filled( little 1 gallon vac) and then lose it's suction, of course right when filter was spun off and I was trying to inspect it! lost about 3 gallons till i spun old filter back on and got the boy to come hold vac hose with an air gap in it. Hope to get fluid today yet if the snows let me get out after work.

Gary Fowler · Jan 21, 2014

mmargush said:
changed the filters last night. everything looked ok. I only bought a gallon to refill teh system with and had troubles with the vacuum trick. I actually had fluid suck into the vacuum and then it filled( little 1 gallon vac) and then lose it's suction, of course right when filter was spun off and I was trying to inspect it! lost about 3 gallons till i spun old filter back on and got the boy to come hold vac hose with an air gap in it. Hope to get fluid today yet if the snows let me get out after work.

Did you find an old gasket still in place on the tractor?

Gary Fowler · Jan 21, 2014

I don't know how you managed to suck any oil out from the filler hole. I actually tried to do that when I overfilled mine during the repair to the filter housing and couldn't get any to come out. I even tried to rig up a hose to go inside, but there is some obstruction about an inch down that wont allow a 3/4" hose to go in. I even tried to suck up oil from the dipstick but didn't manage to get much out of there either. I ended up removing a hose from the stabilizers and pumping it out via the tractor hydraulic system. If you were sucking up oil from the filler hole, you likely had it over filled any way.

Another place to look for an air leak would be the rubber 90 Ell where the steel suction pipe from the filter goes into the pump. Also there are a couple of O-rings on the filter housing itself that may be bad (not likely but another place to check) One is on the intake side of the filter housing where it goes into the tractors reservoir and the other is on the rigid pipe coming out of the filter housing. I recently replaced my filter housing so I know about those AND how difficult it is to get that darned thing off and on. Those O-rings are two different sizes by the way, similar but different.
I would think that if you don't have any leaks there when not running that the O-rings are good. The rubber 90 ell wont leak when not running as it is above the fluid level and it could get damaged from sticks etc if doing brush clearing, so I would closely look at that also if you still have a problem.

dabadas · Jan 24, 2016

mmargush said:
Hello,
First time poster. I've searched with no findings on the same issue I have. My B26 loses it's hydro prime while sitting. Occasionally loses hst while in motion till all the air works out. the problems showed after I did a hydro fluid change with filters. using the gold kubota super udt2 as recommended ..OUCH! I'm wondering could a check valve in the filters have gone bad? or where should I look for an air leak? I've had to replace an oring on the hoe manifold and one on the loader set as well. but an fine after those repairs. Today (30 degrees F) my steering turns fine at idle but as soon as you throttle up it gets tough.... Multiple issues or related?
Any ideas?
thanks in advance!

I'm having the same issue. After sitting there is air in the hydraulics. But not in the HST. After idling and the hydraulics start working, I notice that when I rev it up they stop. Got to be sucking air from somewhere. I checked the rubber hose and the clamps seemed a little loose so I tightened them up. It didn't help. I have changed the oil and filters. The old gasket came off with my old filters so I don't think that is the problem. How tight should I tighten them? I'll be following along to see what happens

dabadas · Jan 26, 2016

Any help?

dabadas · Feb 4, 2016

nothing?

dabadas · Feb 6, 2016

i guess is no one here anymore

Jj1479 · Feb 7, 2016

Might be an issue with the relief valve. Or even the pump might be going out.

CurtisC · Feb 8, 2016

Don't mean to hijack the thread but I had what sounds like a similar problem on my B26TLB after 400 hr. service which included filter changeouts and new load of super UDT. See post:
http://www.tractorbynet.com/forums/kubota-owning-operating/348415-b-26-hydraulic-pump-noise-post4297282.html#post4297282
Since then have run or fully stroked all hydraulics with no improvement. Went to plow after the big snow (coldest start since the service) letting tractor warm up for a good 10-15 minutes and had the now common whine at start up. After plowing a minute or so the tractor forward progress slowed down to almost stop while holding speed control pedal in same position and with no change in engine RPM. Came off speed control pedal and let engine run a bit tried it again and the tractor started moving then struggled again, I shut down it and checked hyd. fluid which was about a quart low. I'm not sure where it went with no signs of external leakage but this was the first time I'd checked it in a while and since removing the Hoe for the grading blade. Topped it off and restarted, the speed control was better - as I continued to plow and fluid warmed up, whine subsided and everything ran fine.
I suspect the culprit is something from the service maintenance process since problems started pretty much right after. The discussion about gasket leaks on hydraulic oil filter (mounted on side of tank) caught my attention. Unfortunately it will be a month or so before I'm back to check it out. In the mean time here are my thoughts:
1) I most likely have an air leak at the hydraulic filter interface mounted on side of tank. Keep me straight, but this filter is downstream of the pump and sees negative pressures whereas the HST filter is upstream and sees only positive pressure.
2) The performance improvement over time is likely due to gasket expansion/sealing taking place at the filter interface as things warm up?
This would explain why the colder it gets the more pronounced the problems are at startup.
3) Air ingestion in the suction line would that also account for the increased whine.
4) I did use WIX filters but wouldn't think filter failure or partial failure other than at the gasket sealing interface would result in what I'm experiencing.

Thoughts from you guys that know hydraulics??

CurtisC · Feb 8, 2016

Don't mean to hijack the thread but I had what sounds like a similar problem on my B26TLB after 400 hr. service which included filter changeouts and new load of super UDT. See post:
http://www.tractorbynet.com/forums/kubota-owning-operating/348415-b-26-hydraulic-pump-noise-post4297282.html#post4297282
Since then I have run or fully stroked all hydraulics with no improvement. Went to plow after the big snow (coldest start since the service) letting tractor warm up for a good 10-15 minutes and had the now common whine at start up. After plowing a minute or so the tractor forward progress slowed down to almost stop while holding speed control pedal in same position and with no change in engine RPM. Came off speed control pedal and let engine run a bit tried it again and the tractor started moving then struggled again, I shut down it and checked hyd. fluid which was about a quart low. I'm not sure where it went with no signs of external leakage but this was the first time I'd checked it in a while and since removing the Hoe for the grading blade. Topped it off and restarted, the speed control was better - as I continued to plow and fluid warmed up, whine subsided and everything ran fine.
I suspect the culprit is something from the service maintenance process since problems started pretty much right after. The discussion about gasket leaks on hydraulic oil filter (mounted on side of tank) caught my attention. Unfortunately it will be a month or so before I'm back to check it out. In the mean time here are my thoughts:
1) I most likely have an air leak at the hydraulic filter interface mounted on side of tank. Keep me straight, but this filter is downstream of the pump and sees negative pressures whereas the HST filter is upstream and sees only positive pressure?
2) The performance improvement over time is likely due to gasket expansion/sealing taking place at the filter interface and/or as fluid warms up the pump creates less negative pressure to bring the oil up from the reservoir?
This would explain why the colder it gets the more pronounced the problems are at startup.
3) Air ingestion in the suction line would that also account for the increased whine from the pump.
4) I did use WIX filters but wouldn't think filter failure or partial failure other than at the gasket sealing interface would result in what I'm experiencing.

Thoughts from you guys that know hydraulics??

dabadas · Feb 8, 2016

I have a whine also. I can bleed off the air and everything works perfect. But, it can sit overnight and when I start it the next day the pump whines and I have air again. The steering will be hard to turn but after a little working back and forth the steering starts working and the HST works. But I have no hydraulics. No front loader no backhoe no 3 point hitch. Nothing works till I bleed the air off. It should not be losing its prime. I've taken the suction line off and the filter bracket and checked them. Changed filter, o-rings and the rubber elbow at the pump. It still loses its prime. Is there something else it could be? Short of buying a pump? THANKS

CurtisC · Feb 9, 2016

dabadas,
In my internet travels this is what I came up with on hydraulic gear pumps: Whine or excessive noise is caused by either cavitation or aeration. Cavitation occurs when the pump is unable to draw oil creating a vacuum which then results in the oil that is present vaporizing. Aeration would come from air being introduced from the suction side. Both situations result in an implosion of the vapor bubbles as the gas is compressed creating a multitude of little shock waves that erode the pump chamber wall and wear plate. Both also result in extra noise or whine at the pump. I'm clearly no hydraulics expert but I'd expect a worn pump to have reduced output flow but not be the actual entry point for aeration (except where suction line connects to the body). Just curious, are you using Kubota filters and did the problem occur gradually over time or was it good one day bad the next? In my case I'm still suspecting the WIX filter I put in as either defective and causing too much flow restriction particularly with high viscosity (cold) oil or because I've got a bad seal since problems showed up after filter change. I've used WIX before and had good luck but I think the next one I put in will be a Kubota. FYI I thought this discussion on the merits of suction side filters in hydraulic systems interesting - Suction Filters in Modern Hydraulic Systems.

dabadas · Feb 9, 2016

OK Here is the back ground. I purchased this backhoe on 1-17-2016 used. It worked fine I loaded it on the trailer and drove the 7 hours home. waited till later that day to unload it. When I started it up nothing worked. Front loader, backhoe, 3 point hitch, steering or HST. I checked the fluid and added about a quart. finally got it working and the fluid foamed out the overflow tube from all the air (it looked milky( but it wasn't water in it. I drained the fluid and put on new HST and hydraulic filters. It had Kubota filters on it but I put Car Quest filters. (friend that works for Hertz says that's all they use). I have removed and inspected the metal suction line and the filter bracket. I also changed the o-rings and the rubber elbow where it attaches to the pump. I also took the pump off and tore it down and inspected it. after getting the air out everything works great. the pump has great pressure. After letting sit for 1 hour everything still works. But, After sitting all night the air is back. The steering and HST is not as bad it will start working rather quickly. But, the front loader and backhoe nothing full of air. I would replace the pump if I knew that would fix it. But I hate to take a 800 dollar gamble. I have no idea why its losing its prime.

100 td · Feb 9, 2016

Have you by chance done the checks/operation that I listed on the Orange tractor forum?

dabadas · Feb 9, 2016

Are you talking about the pressure tests?

100 td · Feb 9, 2016

No (but pressure tests would be good), simply the sequence of events listed to ensure hydraulic circuit is minimal, all valves are in the correct place and not dead heading the pump, and there is no restriction to air flow back into oil reservoir to create a negative pressure at pump. Just the tests/checks listed