CAT 053-5758 PLUNGER

CAT 053-5758 is a Caterpillar genuine hydraulic pump plunger (pure original factory information, no additional description). It is compatible with high-pressure hydraulic pumps (such as main pumps and pilot pumps) in equipment such as C7/C9 engines, 320D/323D excavators, and 950H/966H loaders. It is used in conjunction with plunger sleeves, return springs, and seals for the reciprocating motion of the high-pressure chamber, achieving hydraulic oil pressurization and quantitative delivery, ensuring stable hydraulic system pressure and precise flow control.

Cat Core Parameters and Information

Item Details
Part Model: CAT 053-5758 (0535758) Hydraulic Pump Plunger

Type: Solid plunger, suitable for axial plunger pumps, used for high-pressure oil chamber volume changes and pressure build-up

Material: 42CrMo alloy steel, surface nitrided (HV900-1100), uniform hardness, wear-resistant and corrosion-resistant, suitable for high-pressure hydraulic oil environments

Key Dimensions: Diameter 28 mm, Length 85 mm, Head ball diameter 12 mm, Rod diameter 22 mm, Weight 0.32 kg, Fitting clearance 0.002-0.005 mm

Operating Parameters: Rated working pressure 35 MPa, Maximum instantaneous pressure 42 MPa, Suitable pump speed 1800 rpm, Reciprocating frequency 30 Hz

Sealing Structure: Head equipped with PTFE+NBR combined sealing ring, rod equipped with bidirectional lip sealing ring, preventing high-pressure oil leakage and low-pressure chamber contamination

Applicable Temperature: -40℃ ~ +120℃, suitable for hydraulic system oil temperature environments.

Accuracy Grade: Dimensional tolerance ±0.001 mm, surface roughness Ra≤0.05 μm, meeting high-pressure sealing and motion accuracy requirements.

Compatible Models and Assemblies:

Compatible Parts: Plunger sleeve (053-5759), return spring (053-5760), seal ring (053-5761), plunger slipper (053-5762)

Compatible Equipment: CAT 320D/323D excavators, 950H/966H loaders, D6R bulldozers, etc., equipped with C7/C9 engines, used for high-pressure oil delivery in the hydraulic main pump and pilot pump.

Matching Parts: 053-5758 plunger, 053-5759 plunger sleeve, 053-5760 return spring, 053-5761 seal ring, 053-5762 Plunger Slipper
Installation and Maintenance Points
**Before installation, clean the plunger and plunger sleeve, ensuring they are free of burrs, oil, and impurities. Inspect the plunger surface for scratches and ensure the nitrided layer is intact, and the sealing rings are in good condition.**

Use a specialized tooling to vertically press the plunger sleeve in, ensuring the clearance meets requirements. The return spring should be pre-compressed by 10-12 mm to ensure smooth plunger return.

After installation, test the plunger’s reciprocating motion for smooth movement without jamming, and check for leaks in the high-pressure chamber. The pump should start with stable pressure and no abnormal noise.

Maintenance: Check plunger wear and sealing condition every 2000 working hours. Replace the plunger immediately if leaks or pressure fluctuations occur to prevent hydraulic system malfunctions.