Direct answer
“370” and “slow boom” are not enough to choose a pump or cylinder repair. Confirm the full model and record whether the complaint concerns raising speed, lifting force, lowering or unintended movement. Those descriptions should remain separate in the service request.
Scope and safety
This is a symptom-recording and service-handoff guide, not a procedure for testing or adjusting the machine. Follow the exact machine manual and displayed safety instructions. Keep clear of moving equipment and suspected pressurized leaks. Shutdown alone may not remove stored pressure; hydraulic work and attachment support require the correct procedure and qualified personnel.
Describe the affected movement
Record which boom direction is affected and whether other functions were also slow during normal work. Include the attachment in use, displayed warnings and whether the issue appeared suddenly or gradually. Do not conduct a maximum-height drift experiment.
Add the maintenance context
Provide recent hydraulic service, filter identification and any work on cylinders or control valves. Use available service records rather than estimating pressures. Report existing leaks from a safe location.
Request professional confirmation
Ask for a test report identifying the machine serial range, manual procedure, test conditions and conclusion. Low speed alone does not identify a failed cylinder seal. Pressure adjustments and supported-attachment tests belong to personnel using the correct equipment and instructions.
Service handoff record
| Record | Information to supply |
|---|---|
| Identification | Full machine model and serial; engine or attachment identity where relevant. |
| Complaint | The affected function, direction, timing and original screen message. |
| History | Recent service, changed parts and existing test reports; mark missing information as unknown. |
| Diagnosis | Technician’s confirmed component, applicable manual reference and repair scope. |
Frequently asked questions
Is there one pressure setting for every Zoomlion 370?
This guide does not establish a setting. Obtain the value and test procedure for the exact model and serial range.
Does boom drift prove the piston seal has failed?
The observation should be reported, but it is not a component diagnosis. Have the holding and control functions assessed according to the machine procedure.
Sources and scope of evidence
- Zoomlion service support — manufacturer documentation or support access; obtain the reference for your exact machine.
- Caterpillar hydraulic hose inspection and pressure safety — general hydraulic inspection and stored-pressure safety.
These public sources provide documentation/support routes and general safety context. They do not verify a model-specific fault-code definition, pressure setting or repair case. This guide therefore supplies no such specifications. Source links checked 14 September 2026.
Related guides
- Excavator Hydraulic Pump Failure Symptoms and Next Checks
- How to Check Parts Fitment Before an International Order
Parts identification after diagnosis
Danch Machinery supplies genuine parts. Send the confirmed part number, machine serial number and clear identification photographs for an availability and fitment inquiry. A symptom description does not establish fitment or current stock.
Request a parts identification check
About this guide
Published by Danch Machinery as general parts-identification and service-planning information. It is not a signed technical inspection or a machine-specific repair approval. Refer to the sources and scope stated in the article; confirm service procedures and fitment with the current manufacturer documentation for the exact machine.
Machine configurations and service requirements can differ by model, serial number and market. Confirm procedures and fitment with the current manufacturer documentation for your exact machine.
