B26 tlb hydraulic issues

[aczlan]

Be careful replacing the rubber elbow. I replaced my pump and elbow and when I would rev the engine it start making a noise. Come to find out it sucking it shut causing the pump to start cavitating and whinning. Put the old hose back on problem solved. I couldn't squeege the old one but I could the new one.

Did the old one have a spring or coiled wire inside that needed to be transferred to the new one?

Aaron Z

 

[rScotty]

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. 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 just saw this thread and haven't read it through. So forgive me if this has been mentioned. But the original post reminded me of a problem that may or may not be unique to the M59. Maybe all Kubota TLBs are built the same way? Anyway, the M59 has a couple of hydraulic filters with thick gaskets at the top. That end of the filter has a thick steel end piece threaded in the middle with what looks like a pipe thread. Both filters mount in the same way; they simply are hung vertically by screwing them onto a pipe nipple which in turn screws into the filter mounting housing. Design wise, mounting a filter doesn't get much simpler - or more problematic - than that.

The problem comes about because a person is removing that filter can't know how much of the unscrewing torque was expended removing the filter from the pipe nipple and how much was used to unscrew the other end of the pipe nipple from the filter housing.
I can't tell you how many times I've reached up there only to find that the pipe nipple has backed out of the housing and is is loose enough to be jiggling around. Then you need to grap onto the nipple somehow and screw it back up into the housing block before continuing with the filter change.

Looseness at that joint could certainly create enough of a path for air or fluid to leak there and make the prime to the hydraulic pump irratic. The symptoms would be exactly what the original poster described. And yes, it would also affect power steering. I don't know the details on how the whole hydraulic system is vented or what areas are submerged, but theres at least a possibility that such a leak as I'm describing would also be entirely internal, allowing air or hydraulic fluid to leak between the pipe nipple threads and the housing above the filter without any sign of a leak externally. There would be no external clues. Luckily the fix is easy; be sure to tighten up that nipple each time you change filters.
good luck,
rScotty

 

[dabadas]

Did the old one have a spring or coiled wire inside that needed to be transferred to the new one?

Aaron Z

no it didnt

 

[CurtisC]

I thought I'd share some follow up results on issues I had with whine and poor cold weather pump performance that started after I did 400 hr. maintenance (including installation of new WIX oil filters). Maintenance was performed in 2015 and I noticed noise and performance issues becoming more prominent as it got colder. Summer of 2016 I changed out the 90 degree rubber elbow on the suction line with no noticeable difference and installed a tank heater. I got through the following winter with no hard stalls as long as the oil was heated up before starting but still had the whine and poor performance until the oil really got heated up. The problem diminished last summer and got I busy on other things so no filter change. This winter problem was back but I put off the filter work until a scheduled trip with tractor to Florida.
Finally got around to the filter change and noticed a significant noise reduction at start up and during first use. The tractor won't see another cold start till next winter so I'm not sure all problems are fully resolved but there was a clear improvement after installing new Kubota filters.
So I am officially on-board, only Kubota hydraulic oil and filters from now on. I just hope the pump didn't suffer to much due to my laziness and trying to save a few bucks.

 

[100 td]

Looseness at that joint could certainly create enough of a path for air or fluid to leak there and make the prime to the hydraulic pump irratic.

The nipple coming loose and needing to be done up its valid, but as it is totally inside the fluid path, no air would "leak in" and reduce prime. If there is any air there it reduces prime anyway as it goes through the filter or if it could bypass through the thread tolerances. So any air that is at that point is already in the system from somewhere else, it doesn't create additional air.

 

[rScotty]

The nipple coming loose and needing to be done up its valid, but as it is totally inside the fluid path, no air would "leak in" and reduce prime. If there is any air there it reduces prime anyway as it goes through the filter or if it could bypass through the thread tolerances. So any air that is at that point is already in the system from somewhere else, it doesn't create additional air.

You may be right. I do like your argument, and can see where it would be valid if the filter's mounting was loose - but still rigid enough when tightened to keep all the inside parts safely within the fluid bath. If your view of the fluid path happens, the only air available would be a finite amount trapped within the system by the filter change. At most, the volume of air would then be the volume of the filter cannister minus the denser parts of the filter itself.
Is that enough air to cause a cavitation problem?? I've no idea.... I'd hope not.....

The specific concern I was trying to get to in my post was with the way the filter cannister is screwed into place onto a threaded pipe nipple that in turn is threaded into the transmission housing. With that sort of double-ended mounting system, and with no way to positively lock the upper thread, there is no way a mechanical person removing a filter canister can know how much he has just loosened the mounting pipe nipple from the transmission housing itself. I was surprised at how far mine unscrewed. And wouldn't have suspected it to be so easily undone. I just happened to touch it with my finger and felt it wobble.
If I hadn't noticed it, and just reassembled with the transmission end of the nipple loosened, the filter's face seal might not seal tightly enough to prevent air from getting in - or fluid from getting out. Either situation could contribute to a problem.

If I can find a decent hydraulic diagram of the M59 I'll double check the fluid pathway & immersed parts. Again, this is for the M59, I don't know what kind of filter mounting system that the B series TLBs use.
Anyway, thanks for the correction.
rScotty

 

[100 td]

The specific concern I was trying to get to in my post was with the way the filter cannister is screwed into place onto a threaded pipe nipple that in turn is threaded into the transmission housing.

As previously noted, the nipple coming loose and needing to be done up its valid, and very worthy of highlighting to others, which is why I also noted it.
I expect the reason they have gone this way is the ease of manufacture compared to casting with an extended spigot. Also the strength of the metal nipple (steel I would suspect) threaded into a socket is greater than an aluminum spigot. Some suitable locking compound, compatible with oil, or the deformation of one end of the nipples thread would fix the situation.
My comments about the air was not a criticism, but just meant to explain that external air can't enter at that point, however I may have done that job poorly. It has to get past the outer filter gasket to get in. The nipple is simply a piece of threaded pipe in the circuit, the oil is designed to go through the center of it, but miniscule amounts may go around it through the threads to the same point, thereby bypassing the filter media. Air would do the same, but either way, it's the same path, with no external entry.
I have a feeling some L series are prone to having their filter knocked and the aluminum spigot breaking off, necessitating a replacement housing.

 

[OrangeOrangutan]

CurtisC-

I have same machine. My rubber hose/ boot connected to the hydro pump from the suction line has a large crack in it. Hydro oil pouring out obviously. Tractor has under 50 hrs and out of warranty. I ordered two boots one to replace and one as future back up. Have to do my own repair....Can i pull steel suction line off and maneuver the boot back onto the hydro pump or does the hydro pump need to come off too for a better fit? There isnt much room against the block.

It looks like original boot already dry rotten and split.

Any help appreciated.

 

[djsll]

I have a B26 with a leak on the top of the hydraulic tank. Thought it might be the O ring and seals but when I removed the tank and did a leak test with air pressure, turns out it is leaking around the mounting bracket. It is leaking on the end of the bracket on both sides. Has this happened to anyone else? I was shocked really because the tank does not have any damage to it. Almost like it is a manufacturers defect.