DRIVING & CHASSIS - TROUBLESHOOTING HS120V 4.1 DRIVING HYDRAULIC SYSTEM/BRAKE 4. TROUBLESHOOTING G5:9HM:=FGH 8F=J=B;7 756=B 9B;=B9 9@97HF=7GMGH9A =B89L 3 -16 GMW-0035 SYMPTOM CAUSE SOLUTION The driving force on one side is weak. (Identical for the forward driving and reverse driving) Insufficient oil in the tank • Check for leakage and add the oil as necessary. Loose pedal linkage • Adjust and reconnect the pedal linkage. Broken pump neutral bracket • Replace it. Check the neutral bracket (for loose bolt or excessive play). Damaged high-pressure line • Replace the line. Check the pump mounting bolt and HST motor.
Damaged drive chain • Check the chain and the chain connecting linkage Replace any damaged part. Damaged HST motor shaft • Replace any defective part. Check the motor mounting bolt. Defective pump • Check and repair the defective part. Faulty HST pump. The driving force on one side is weak at first, but, in a few minutes, the driving force on both sides becomes weak. • Check and repair the defective part. Excessive internal oil leakage or damaged control pump motor or HST motor • Check and repair any defective part. Clean the tank and the hydraulic lines. Replace the filter. Check the engine RPM and the hydraulic oil. The driving force on one side is weak.
(Only for the forward driving or reverse driving) Defective relief valve of the valve block • Replace the relief valve. Stuck or damaged shuttle valve of the HST motor • Check and replace any defective part. The driving force on one side is lost. (No hydraulic pressure delivered at all) Insufficient oil level in the oil tank • Check for oil leakage. Add the oil. Damaged coupling between the engine and pump • Check and replace any damaged part. Check for misalignment. Malfunctioning HST pump • Check and replace any damaged part. The driving force on both sides is lost. (No hydraulic pressure built at all) Damaged spline coupling (in the control pump) • Check and replace any damaged part.
Damaged implement pump shaft • Check and replace any damaged part. The driving force on both sides is lost. (Overall hydraulic pressure built) Malfunctioning HST pump • Check and replace any damaged part. Defective relief valve of the HST pump • Check and replace any damaged part. Excessive internal leakage • Clean the tank and hydraulic lines. Replace the filter. Defective control pump or HST motor • Check the engine RPM and hydraulic oil specification. Excessively saggy drive chain • Adjust