My B20 has hydraulic cavitation, foams the oil, loader and power steering are jerky, and the HST works well at cold start but after a short run time it just stops moving until it sets for a little while and it’s incredibly slow moving in high med and low
B20 hydraulic noise
- Thread starter Trigger069
- Start date
Your symptoms point to air in the system. First, is the transmission fluid at the proper level? When were the fluid and filter changed, and what fluid was used?
Carefully check the suction line from the transmission case to the pumps, including the steering controller and cooler. Any leaks there can cause the problem, and they're not always obvious, since there's little to no pressure.
When I bought my used L35 it had a chirp when shifting. I replaced all the short hoses in the suction side. Then I found a crushed spot in one of the steel sections of line. After repairing that, the problem went away.
I have changed both hydraulic and transmission filters several times new super udt2 fluid change now change 3 with tractor supply udt compatible fluid. Replaced all the short rubber sections from the side of the trans to main suction lines to the front mounted pump and cooler
First, there has been a lot of back-and-forth on here about SUDT vs other oils, including TSC. Kubota doesn't publish its specs, so 'compatible' is not Kubota-endorsed. Most on here say stick with Kubota if you have hydrostatic or GlideShift. There are reports of noise, poor shifting and other problems with non-UDT. There's a guy on here now looking at hydro repairs that exceed the value of his tractor, some attribute to possible non-K oil.
Now, back to your original problem. Are you using Kubota filter? Did you possibly leave the old filter gasket on? Filter adapter 030 cracked? The parts diagram below make it look like the suction line goes through the frame. Is that so? Did it possibly wear through? O-rings 150? I don't think there's a screen behind the banjo bolt 130, but I'd check for obstruction there. BTW, those are copper washers so you may have to replace or anneal them when you re-assemble. You could also have a leak in that side branch off 020 - that may be the return from the cooler.
I still think you have a leak.
Filters are kubota not double gasket for sure definitely could be a leak #150 I didn’t even realize were there… further looking into it is needed. I’m wondering what the best method to smoke test it might be check everything including the cooler for possible leaks
I'm not familiar with your model and don't have a WSM available, just parts diagrams, so my help is limited. Looking at them again, it appears there's a third pump. That's a separate charge pump to the hydro. It appears to take suction after the filter on the right side, then through the oil cooler, so any leak in the cooler or those lines could let air in. These pumps have o-ring shaft seals that could leak. I don't know of a pressure or vacuum test method. You might be able to isolate sections and put a little air pressure on them.
You might try a mechanic's stethoscope or screwdriver to pinpoint the noise source. That may provide a clue, at least. Hopefully, more knowledgeable folks will show up.