Kubotan B21 Hydraulic system issues

Philmorley1 · Jun 4, 2011

Hi all,
I have a 2006 B21 TLB that has given me great service to date. However, it recently started displaying some unusual symptoms. It appears that if there is no or low volume load on the unit all of the hyd functions operate normally. however if you have the selector in H (high speed) the tractor will operated properly and sound normal for 5 to 10 seconds. At that time I start hearing a rumbling sound, speed drops off and I back off of the pedal. Also some times when I am moving at a reasonable speed in either L or M setting, while steering and moving an attachment (bucket) all hyd functions just stop. After a few seconds either of the functions mentioned will operate normally again and when checked all of the functions seem restored.

I had a hyd leak that I could not locate and I would add hyd oil when needed. Recently one of my backhoe hoses broke where it had been chafed and I assumed this had been the leak. I replaced this hose, replenished the system and thought all was well. During this past week while doing some grading I noted some leakage where the unit had been sitting for some period and have continued to add hyd oil as necessary. I have degreased the middle housing, hyd assy, hoses, fittings gasket joints, differential and seal areas with several pieces of sheet metal and covers removed for inspection and cleaning. So far after 3 additional hours of operation I can find no leak. At least I haven稚 found any yet.

Please help! The main issues noted in the first paragraph are continuing and I feel could cause more serious damage if not resolved.

J_J · Jun 4, 2011

If the hyd system is leaking and you can not see a leak, check the engine crankcase. If you are losing fluid, Is the crankcase over filled? It has to be going going somewhere. How many times has the hyd reservoir leaked down and you refilled it ?

Philmorley1 · Jun 4, 2011

Thanks for the reply J.J.
I have checked the engine oil level and there seems to be no increase in the reading. I worked the tractor today and still cannot see any leak. There is no sign of leakage under the tractor. I put a large piece of cardboard under there last night and saw nothing this morning. I did notice the other day that the vent on the top of the casing next to the fill port had some discharge and i assumed that because I was working the tractor pretty hard that the case was venting some hot gases...?? Anyway, none of that today and still no leakage.

I just realized that i had misspelled Kubota in this thread; please excuse my spelling and typing errors.

Again, today was not a hard day for the tractor. I was real hard for me because i was doing a lot of hand work leveling out and area to be seeded.

Any other ideas?
Phil