Bucket crowd force weak or cylinder rod leaking on your 312? A worn 4I8840 bucket cylinder allows internal piston bypass to cut crowd force below what the machine needs for hard material penetration, while rod seal wear causes external leakage that contaminates the work area. RITO supplies this heavy-duty replacement bucket cylinder to restore full 312-series bucket crowd force and clean seal operation.
Item NO.:
4I88404I8840 Hydraulic Bucket Cylinder Assembly for Caterpillar 312, 312B, 312C excavators. Heavy-duty double-acting bucket 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 312-class bucket duty cycle so the new cylinder restores original crowd force and cycle time from installation.
| Part Number | 4I8840 |
|---|---|
| Part Name | Hydraulic Bucket Cylinder Assembly |
| Compatible Brand | Caterpillar |
| Applicable Models | 312, 312B, 312C Excavator |
| Application | Bucket crowd hydraulic cylinder for Caterpillar 312-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 bucket crowd force for 312-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 312-series OEM specification, providing the hardness and corrosion resistance that determine bucket cylinder seal service life.
Bore honed to OEM surface finish and tolerance for correct piston seal contact and low internal bypass at full 312 bucket pressure.
4I8840 covers the bucket cylinder specification across the listed Caterpillar 312-class models, keeping fleets on one interchangeable replacement.
Rod and piston seal assembly rated for 312 maximum bucket pressure, with buffer seals that protect the primary rod seal from pressure spikes during hard digging.
FAQ
Q: How do I tell if the 4I8840 bucket cylinder has internal bypass or rod seal leakage?
A: External leakage shows at the rod seal. Internal bypass makes the bucket crowd slowly under load without visible external oil. Stall the bucket against a load and watch for slow drift over 60 seconds.
Q: Can I replace only the seal kit in the 4I8840 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 4I8840?
A: Cycle the bucket 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 4I8840 is correct for my 312?
A: Match the existing cylinder part number against 4I8840 and confirm the machine model is one of: 312, 312B, 312C. 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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