I went to bury my wifes horse that had to be put down. The left steering pedal would depress but not stop the tracks, occasionally it would work for a second or two but then stop. Right one works fine. Machine worked great a few weeks ago when I last used it. Has plenty of Hydraulic fluid. I have a repair manual but thought I would ask here as well for the first obvious items to look at. It is weird that it worked some times, maybe the spool valve?
Update, finally got time to work on it. Started by adjusting the brake bands. They were waaay out. Manual calls to torque the adjuster to 9kgm which is 65 lbft, then back off 1.5 turns. Amazing that it turns and I have brakes
I opened the steering fluid dipstick and fluid poured out, like 10 gallons. No idea how it got that overfilled so I am going to drain and refill with new oil.
The oil had to come from somewhere. Check the other fluid levels and see if they are low. Not sure how a Komatsu is set up but maybe a seal is leaking between different oil compartments.