Boom lift force dropping or hydraulic oil weeping from the rod on your 312? A worn 1251545 boom cylinder lets internal piston bypass bleed away lift force until the machine can no longer hold a loaded boom, while a scored rod seal leaks oil across the cylinder head. RITO supplies this heavy-duty replacement boom cylinder to restore full 312-series boom lift and clean, seal-tight operation.
Item NO.:
1251545 / 4I88381251545 Hydraulic Boom Cylinder Assembly for Caterpillar 312, 315, 318, 312B excavators. Heavy-duty double-acting boom cylinder with chrome-plated precision rod and a honed bore produced to OEM specification. Chrome layer thickness, honing surface finish and the multi-layer piston seal assembly are matched to the 312-class lifting duty cycle so the new cylinder delivers original boom holding force and cycle time from installation.
| Part Number | 1251545 / 4I8838 |
|---|---|
| Part Name | Hydraulic Boom Cylinder Assembly |
| Compatible Brand | Caterpillar |
| Applicable Models | 312, 315, 318, 312B Excavator |
| Application | Main boom lift 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 boom lifting and holding 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 determines boom cylinder seal service life.
Bore honed to OEM surface finish and dimensional tolerance for correct piston seal contact and low internal bypass at full 312 working pressure.
1251545 covers the boom cylinder specification across the listed Caterpillar 312-class models, keeping fleets on one interchangeable replacement.
Rod and piston seal assembly rated for 312 maximum boom pressure, with buffer seals that protect the primary rod seal from pressure spikes during heavy lifts.
FAQ
Q: How do I tell if the 1251545 boom cylinder has internal bypass or rod seal leakage?
A: External leakage is visible at the rod seal. Internal bypass causes slow boom drift when held stationary under load without visible external oil. Hold the boom at mid-stroke and watch for downward drift over 60 seconds.
Q: Can I replace only the seal kit in the 1251545 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 1251545?
A: Cycle the boom 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 1251545 is correct for my 312?
A: Match the existing cylinder part number against 1251545 and confirm the machine model is one of: 312, 315, 318, 312B. 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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