If the displacement of the piston pump is not zero when it is in neutral, it may indicate a problem with the pump's control valve or other internal components. Here are some steps you can take to troubleshoot and resolve the issue: Check the control valve: The control valve is responsible for directing the oil flow to the corresponding hydraulic cylinder. If the valve is stuck or not working properly, it can cause the pump to keep pumping oil even though it should be in the neutral position. Check valve for wear or damage, clean or replace if necessary. Check the hydraulic cylinder: If the control valve is working properly, the problem may be in the hydraulic cylinder itself. Check the cylinder for damage, leaks, or other issues that could prevent it from returning to neutral. Check the mechanical parts of the pump: If the control valves and hydraulic cylinders are working properly, the problem may be in the mechanical parts of the pump. Check for worn or damaged parts and replace as necessary. Check the pump level and pressure: Low fluid levels or incorrect pressure settings can also cause the pump to continue pumping oil when it should be in the middle. Check fluid level and pressure settings and adjust as necessary. Consult the manufacturer's instructions: If you are unsure how to troubleshoot or repair your displacement pump, consult the manufacturer's instructions or contact a qualified technician for assistance. When working with hydraulic equipment, it is important to follow proper safety procedures. Perform regular maintenance: Regular maintenance is key to keeping your piston pump up and running. Make sure to follow the manufacturer's recommended maintenance schedule, which may include tasks such as changing fluids, cleaning or replacing filters, and inspecting and replacing worn parts. Consider consulting a professional: If the problem persists after trying these troubleshooting steps, it may be time to consult a professional technician. They can provide further insight into specific issues and recommend the most appropriate solutions. It is important to resolve any problems with your displacement pump as soon as possible to avoid further damage or downtime. 90R180-KA-2-BC-80-T-C-C8-J-00-FAC-35-35-24 90R180KA2BC80TCC8J00FAC353524 90-R-180-KA-2-BC-80-S-C-F1-J-03-NNN-40-40-24 90R180KA2BC80SCF1J03NNN404024 90-R-180-KA-1-NN-80-T-M-F1-J-03-FAC-35-35-24 90R180KA1NN80TMF1J03FAC353524 90-R-180-KA-1-NN-80-T-M-F1-H-03-FAC-26-26-28 90R180KA1NN80TMF1H03FAC262628 90-R-180-KA-1-NN-80-T-M-C8-J-03-NNN-32-32-24 90R180KA1NN80TMC8J03NNN323224 90R180-KA-1-NN-80-T-M-C8-J-03-NNN-32-32-24 90R180KA1NN80TMC8J03NNN323224 90-R-180-KA-1-NN-80-T-M-C8-H-00-NNN-26-26-24 90R180KA1NN80TMC8H00NNN262624 90R180-KA-1-NN-80-T-M-C8-H-00-NNN-26-26-24 90R180KA1NN80TMC8H00NNN262624 90-R-180-KA-1-NN-80-T-C-F1-J-05-FAC-35-35-24 90R180KA1NN80TCF1J05FAC353524 90R180-KA-1-NN-80-T-C-F1-J-05-FAC-35-35-24 90R180KA1NN80TCF1J05FAC353524 Consider replacing the pump: In some cases, it may be more cost-effective to replace the plunger pump than to attempt to repair it. If the pump is old or badly damaged, investing in a new pump may be more efficient and reliable than continuing to service the old one. Check for other possible causes: There may be other factors causing the pump to continue pumping oil when it should be in neutral, such as improper installation or misuse. Make sure to check for all possible causes and fix any issues as needed. Overall, it is important to resolve any problems with your piston pump promptly and thoroughly to ensure its continued reliable function. Regular maintenance and proper use can help prevent problems at their source. Some additional steps that may help resolve displacement pump problems include: Check the relief valve: The relief valve is an important part of the piston pump that helps regulate the pressure. If the relief valve is stuck open, it may cause the pump to continue pumping oil even when it is in neutral. Check the relief valve to make sure it is working properly and replace if necessary. Check the spool valve: The spool valve is responsible for directing the flow of oil through the pump. A worn or damaged spool can cause the pump to continue pumping oil when it should be in neutral. Check the spool valve and replace if necessary. Check the control valve: The control valve is responsible for regulating the flow of oil in the pump. A worn or damaged control valve can cause the pump to continue pumping oil when it should be in neutral. Check control valve, replace if necessary. Check the pump casing: The pump casing is the outer casing of the piston pump. Damage to the housing can cause the pump to continue pumping oil when it should be in neutral. Check the pump casing for damage and replace if necessary. By following these steps and ensuring that your displacement pump is maintained and used properly, you can help prevent problems and ensure its continued reliable function. If you are unsure how to troubleshoot or repair your pump, consider consulting a professional technician who can provide guidance and assistance. Check the pressure gauge: A pressure gauge is used to monitor the pressure in the piston pump system. If the pressure gauge is faulty or damaged, it may give inaccurate readings, which can cause problems with the pump. Check pressure gauge, replace if necessary. 90-R-180-KA-1-NN-80-T-C-F1-J-03-FAC-35-35-24 90R180KA1NN80TCF1J03FAC353524 90R180-KA-1-NN-80-T-C-F1-J-03-FAC-35-35-24 90R180KA1NN80TCF1J03FAC353524 90-R-180-KA-1-NN-80-T-C-F1-H-03-FAC-38-14-24 90R180KA1NN80TCF1H03FAC381424 90R180-KA-1-NN-80-T-C-F1-H-03-FAC-38-14-24 90R180KA1NN80TCF1H03FAC381424 90-R-180-KA-1-NN-80-T-C-F1-H-03-FAC-35-35-24 90R180KA1NN80TCF1H03FAC353524 90R180-KA-1-NN-80-T-C-F1-H-03-FAC-35-35-24 90R180KA1NN80TCF1H03FAC353524 90-R-180-KA-1-NN-80-T-C-F1-H-03-FAC-32-32-24 90R180KA1NN80TCF1H03FAC323224 90R180-KA-1-NN-80-T-C-F1-H-03-FAC-32-32-24 90R180KA1NN80TCF1H03FAC323224 90-R-180-KA-1-NN-80-T-C-C8-J-03-NNN-35-35-20 90R180KA1NN80TCC8J03NNN353520 90-R-180-KA-1-NN-80-T-C-C8-J-03-FAC-35-35-20 90R180KA1NN80TCC8J03FAC353520 Check the oil inlet and outlet valves: The oil inlet and outlet valves are responsible for regulating the flow of oil in and out of the pump. If these valves are worn or damaged, they can cause problems with the pump's performance. Check inlet and outlet valves and replace if necessary. Check oil level and quality: Correct oil level and quality are critical to reliable operation of a piston pump. If the oil level is too low or if the oil is dirty or contaminated, it may cause problems with the performance of the pump. Check oil level and quality, and refill or replace oil as necessary. Check the alignment of the pump: Improper alignment of a plunger pump can cause problems with its performance, including the inability to achieve zero displacement in the middle position. Check pump alignment and adjust if necessary. Check the pump installation: Piston pumps must be installed securely to prevent problems with their performance. If the pump is installed incorrectly, it may cause problems with its performance. Check pump installation and adjust if necessary. Check the drive system: The drive system is responsible for powering the piston pump. If the drive system fails or is damaged, it can cause problems with the performance of the pump. Check the drive system and replace any faulty or damaged parts. Check for Other Mechanical Issues: Various other mechanical issues can cause problems with the performance of your displacement pump. These may include worn or damaged seals, bearings or other components. Check the pump for any other mechanical problems and repair or replace any faulty parts.