I have a mid 2000s Kubota R520s that I bought used and is kind of a clunker. Since I’ve owned it, hydraulic fluid overflows out of the brake fluid reservoir while operating it after a short period of time. The LST oil pressure light stays on during operation and despite that, the tractor still works great (except poor traction, don’t know if that’s just soft muddy ground or torque issue) and doesn’t seem to lack any lifting power. No unusual sounds from the engine or anything either. Recently, I noticed the loader moving unusually slow and the overflowing hadn’t happened in a while. I topped off the hydraulic fluid after realizing the level was below what it should be and soon after the loader worked great again. Shortly after operating, the overflowing continued again, and the fluid level dropped back down which confirms the brake fluid reservoir is indeed connected to the main hydraulic tank. The overflowing seemed to stop a while back (or took way longer to start overflowing) after it had lost too much fluid, so topping it up confirms again they’re related.
After turning the tractor off, the fluid continues to overflow until the fluid level falls below the top of the reservoir. Basically, it doesn’t just go back down to where it came.
The brakes seem to work fine and doesn’t seem to force any more fluid when I press the brakes.
The manual gives zero useful information on the brake fluid reservoir and from consulting chat gpt, it could be a faulty pressure relief valve or a bent/clogged return line causing oil to be forced through the brake reservoir and through the vent holes in the cap. This makes sense but I haven’t heard much about faulty pressure relief valves causing leaks/overflows, more so them causing the loader not to work.
Let me know if I’m on track with this, I have less than a year of experience driving tractors and this issue has been haunting me for months. Much appreciated!
After turning the tractor off, the fluid continues to overflow until the fluid level falls below the top of the reservoir. Basically, it doesn’t just go back down to where it came.
The brakes seem to work fine and doesn’t seem to force any more fluid when I press the brakes.
The manual gives zero useful information on the brake fluid reservoir and from consulting chat gpt, it could be a faulty pressure relief valve or a bent/clogged return line causing oil to be forced through the brake reservoir and through the vent holes in the cap. This makes sense but I haven’t heard much about faulty pressure relief valves causing leaks/overflows, more so them causing the loader not to work.
Let me know if I’m on track with this, I have less than a year of experience driving tractors and this issue has been haunting me for months. Much appreciated!
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