Arm crowd slow or rod seal weeping on your R220LC-9S? A worn 31Q6-50131 arm cylinder loses piston seal integrity and drops arm crowing force below what the machine needs for hard digging, while a scored rod seal leaks hydraulic oil across the cylinder head. RITO supplies this heavy-duty replacement arm cylinder to restore full R220-series arm crowd force and clean, seal-tight operation.
Item NO.:
31Q6-50131 / 31Q6-5631Q6-50131 Hydraulic Arm Cylinder Assembly for Hyundai R210LC-9, R220LC-9S excavators. Heavy-duty double-acting stick cylinder with chrome-plated precision rod and a honed bore produced to OEM specification. Piston seal integrity and rod chrome finish are matched to the R220-class crowd duty cycle so the new cylinder restores original arm penetrating force from installation.
| Part Number | 31Q6-50131 / 31Q6-56100 |
|---|---|
| Part Name | Hydraulic Arm Cylinder Assembly |
| Compatible Brand | Hyundai |
| Applicable Models | R210LC-9, R220LC-9S Excavator |
| Application | Arm / stick crowd hydraulic cylinder for Hyundai R220-class excavators |
| Material | High-strength steel body, chrome-plated precision rod |
| Product Color | Yellow or industrial finish |
| Working Temperature | -25°C~+80°C |
| Key Function | Provides hydraulic arm crowd and extension force for R220-series excavator work cycles |
| Condition | 100% New Aftermarket OEM Quality |
| Packaging | Wooden Case Reinforced Carton Neutral Packing Customized Box |
Rod chrome layer thickness and adhesion matched to R220-series OEM specification, providing the hardness and corrosion resistance that determine arm cylinder seal service life.
Bore honed to OEM surface finish and tolerance for correct piston seal contact and low internal bypass at full R220 crowd pressure.
31Q6-50131 covers the arm cylinder specification across the listed Hyundai R220-class models, keeping fleets on one interchangeable replacement.
Rod and piston seal assembly rated for R220 maximum stick pressure, with buffer seals that protect the primary rod seal from pressure spikes during heavy digging.
FAQ
Q: How do I tell if the 31Q6-50131 arm cylinder has internal bypass or rod seal leakage?
A: External leakage shows at the rod seal. Internal bypass makes the arm crowd slowly under load without visible external oil. Stall the arm against a load and watch for slow drift over 60 seconds.
Q: Can I replace only the seal kit in the 31Q6-50131 cylinder?
A: If the rod chrome is undamaged and the bore is within specification, a seal kit repair is economical. Replace the full cylinder if the rod shows pitting, score marks or chrome delamination that would cut the new seals immediately.
Q: What bleeding procedure is needed after fitting 31Q6-50131?
A: Cycle the arm slowly through full extension and retraction five times at low engine speed before applying full load. This purges air and seats the seal assembly before high-pressure operation.
Q: How to confirm 31Q6-50131 is correct for my R220?
A: Match the existing cylinder part number against 31Q6-50131 and confirm the machine model is one of: R210LC-9, R220LC-9S. Provide the machine serial number for cross-reference confirmation.
Q: What quality options are available?
A: We provide original, OEM and high-quality aftermarket versions with stable supply capability.
Q:Why Choose RITO?
A:Listed Factory
Stable&Reliable Quality
OEM Factory for Chinese Top Excavator Brands
Supplier to Fortune 500 Companies
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