assisitant valve staff for XCMG ZL50G/ZL50GL Wheel Loader

product parameters

Product Name: Auxiliary Spool
Part No.: None
Applicable Model: XCMG ZL50G, ZL50GL Wheel Loader
Matching Valve: D32 pilot multi-way valve
Material: Alloy structural steel, quenched and precision ground
Sealing Type: Clearance seal spool
Function: Control auxiliary circuit on-off, flow regulation and neutral holding
Nominal Port Size: 32mm
Medium: Anti-wear hydraulic oil for construction machinery
Working Temperature: -20℃ ~ +80℃
Inspection Items: Diameter check, concentricity test, notch profile inspection, pressure holding test, cycle durability test
Matching Parts: Valve spring, seal gaskets, overload make-up valve

Applicable Scenarios

Installed inside the auxiliary section of D32 multi-way valve, it controls hydraulic attachments such as grapple, snow blade and hammer. Widely used in construction, sanitation and cargo terminals with optional attachments.

• Manufactured strictly per original drawing, consistent dimension and notch profile for reliable interchangeability
• Quenched alloy steel with uniform surface hardness, excellent wear resistance against particle erosion in hydraulic oil
• Pressure balance grooves eliminate hydraulic clamping, deliver steady pilot force and smooth spring return
• Optimized flow notches provide linear speed control, gentle attachment movement and fine positioning
• Precisely controlled clearance balances smooth sliding and low leakage, effectively prevent unintended attachment dropping
• Cost-saving single-part repair solution; replace only the spool instead of the whole valve assembly
• Individual dimension and pressure inspection for stable batch quality, low risk of stuck spool after installation
• Fully compatible with original spring, gaskets and overload valve, no trimming required during assembly

FAQ 

Q：What symptoms appear when the auxiliary spool is worn and scratched?
A：Typical symptoms include attachment creeping down, weak and slow movement, jitter during operation, delayed return and abnormal flow distribution under compound operation.

Q：Does attachment creeping always mean the spool is damaged?
A：No. Check overload make-up valve and cylinder seal leakage first. Exclude these faults before confirming spool wear.

Q：Can I polish and reuse the stuck auxiliary spool?
A：Light dirt clogging can be cleaned temporarily. Scratched spool cannot be repaired by polishing, because it changes the clearance and leads to recurring leakage. New spool is recommended.

Q：Can auxiliary spool interchange with boom or bucket spool?
A：Not interchangeable. They have different notch shape and flow characteristic. Wrong assembly will cause abnormal speed control and safety risk.

Q：What should be noted during installation?
A：Clean valve bore thoroughly, lubricate with clean hydraulic oil, never hammer the spool. Replace gaskets and check return spring tension.

Q：What causes spool scratching most often?
A：Contaminated hydraulic oil and clogged filters are the main causes. High oil temperature and repeated high-pressure shock also accelerate wear.

Q：Do I need to readjust pressure after replacing the spool?
A：The spool itself does not set relief pressure, but pressure test is recommended after assembly to verify relief setting and auxiliary circuit holding performance.