Direct answer
Before selecting a boom cylinder or pump, identify the full Hyundai wheeled-excavator model and distinguish no movement from slow lifting, weak lifting or unintended lowering. A “150” designation alone is not sufficient to establish the hydraulic configuration.
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 machine setup
Record the model plate, attachment, operating mode and the working setup in use when the problem occurred. Include any relevant stabilizer or blade configuration as an observation, without prescribing an alternative setup.
Record what still works
List other movements that remained normal and any screen warning. Explain whether the complaint followed transport, attachment changes or hydraulic service. Do not bypass a safety interlock or open a holding valve to force movement.
Make the diagnosis reviewable
Ask the technician to identify the applicable boom circuit procedure and explain the evidence for the proposed repair. Low pressure or observed drift should not automatically be turned into a pump or cylinder order. Supporting and isolating the attachment must follow the machine 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
Should I remove the boom valve first?
Not on the basis of this symptom guide. Service personnel should select the inspection procedure after identifying the machine and fault.
What should I send for a confirmed cylinder inquiry?
The complete cylinder number, machine serial, mounting details and the confirmed scope: assembly, seals or another identified component.
Sources and scope of evidence
- Hyundai Construction Equipment services and 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.
