9.Model Setting

Trouble Description

External load works on the motor and cavitation and abnormal noise occur when a pumping action is performed. Possible Cause

Foreign matter gotten into the plunger prevents it from moving smoothly and providing counter balance function.

The spring of the plunger is damaged and the counter balance function is not provided.

No spring is set in the plunger and the counter balance function is not provided.

The spring of the check valve is damaged and the counter balance function is not provided.

No spring is set in the check valve and the counter balance function is not provided.

The orifice of the pilot oil path is clogged with foreign matter and the counter balance function is not provided. Countermeasure and Solution

Disassemble the unit to remove the foreign matter. Check the degree of the damage by following the maintenance procedures. If it is still usable, re-assemble it. If it is no longer usable, replace it by using the base plate kit.

Disassemble the unit to remove the foreign matter, replace the spring, and re-assemble the unit.

Assemble a spring appropriately.

Disassemble the unit to remove the foreign matter and then replace the spring.

Assemble a spring appropriately.

Disassemble the unit to remove the foreign matter and re-assemble it.

[5]Troubleshooting for 2nd-speed control function section

Trouble Description

Does not switch to the high-speed rotation.

It switches to the high-speed rotation but switches to the low-speed rotation when the temperature of the hydraulic oil rises. Possible Cause Countermeasure and Solution

Pilot pressure oil has not reached to Ps port.

Foreign matter gotten into between the spool and the base plate prevents the spool from switching.

Abnormal wear in the 2nd-speed control piston section causes pressurized oil leak in the case. Check whether pilot pressurized oil has reached to the Pa port and then inspect and repair the motor by identifying the Causes of problems and countermeasures for it for each piece of equipment.

Disassemble the unit to remove the foreign matter. Check the degree of the damage by following the maintenance procedures. If it is still usable, reassemble it. If it is no longer usable, replace it by using the base plate kit.

Disassemble the unit to replace by using the flange holder kit.

No 2nd-speed control piston is set. Assemble a 2nd-speed control piston in place.

A clogged orifice of the 2nd-speed oil path prevents pressurized oil from reaching to the 2nd-speed control piston. Disassemble the unit to remove the foreign matter and re-assemble it.

Abnormal wear in the 2nd-speed control piston section causes pressurized oil leak in the case. Disassemble the unit to replace by using the flange holder kit.