CAT 6L-1525 BLOCK

The CAT 6L-1525 is a Caterpillar original hydraulic pump cylinder block, compatible with axial piston pumps (such as the CAT 35V series). It is used in high-pressure hydraulic systems to achieve oil suction and discharge circulation, and is suitable for the main pump or pilot pump of equipment such as loaders and excavators. Its core function is to support the piston and form a sealed working chamber, ensuring stable flow and pressure under high-pressure conditions.

Core Technical Parameters

Item Details
Part Model: CAT 6L-1525 Hydraulic Pump Cylinder Barrel

Material: High-strength alloy steel forging, surface nitrided + polished, hardness HV 850-1000, wear-resistant layer thickness 0.15-0.25mm, high pressure ≥35MPa, temperature resistance -40℃ to 120℃, compatible with mineral oil and synthetic hydraulic oil

Key Dimensions: Number of plunger holes: 7/9 (common specification), plunger hole diameter: 22-28mm, cylinder diameter: 100-120mm, length: 80-100mm, locating pin hole diameter: 10-12mm, end face runout tolerance ≤0.01mm, ensuring a tight seal with the distributor plate

Compatible Models: Compatible with CAT 950G/966H loaders, 320D/323D This technology is commonly used in excavators and other hydraulic equipment, particularly in the cylinder block assembly of main hydraulic pumps (such as the 35V250) or pilot pumps. It is also compatible with some Caterpillar industrial piston pumps.

Performance Characteristics: High-pressure sealing design, suitable for working pressures of 25-35MPa. The inner wall roughness of the piston bore is Ra≤0.2μm, reducing piston wear. A nitrided layer enhances wear resistance and extends service life. Suitable for pump speeds of 1500-2500rpm.

Core Functions and Structure:

Volume Chamber Formation: Evenly distributed piston bores on the cylinder block mate with the pistons, forming multiple sealed volume chambers. Rotation with the pump shaft enables oil suction and discharge, converting mechanical energy into hydraulic energy.

High-Pressure Sealing: Tightly fitted to the distributor plate, the end-face sealing strip prevents high-pressure oil leakage, ensuring stable hydraulic system pressure and meeting sealing requirements under high-pressure conditions.

Support and Guidance: Provides precise guidance for the pistons, ensuring coaxiality of the pistons’ reciprocating motion within the bores, reducing uneven wear, and improving pump volumetric efficiency and service life.

Suitable for high-pressure systems: Made of alloy steel with nitriding treatment, it can withstand the impact of high-pressure hydraulic oil, making it suitable for the frequent start-stop and large load fluctuation conditions of construction machinery, ensuring stable pump operation.

Installation and Maintenance Points
Installation Specifications: Clean the cylinder body surface and plunger bore to remove oil and impurities. Check the cylinder body for cracks and deformation, the plunger bore inner wall for scratches, and the nitriding layer for peeling.

During installation, apply hydraulic oil to lubricate the mating surfaces of the plunger and cylinder body to ensure flexible plunger movement. The contact surfaces between the cylinder body and the distributor plate must be cleaned. After installation, check the end face runout to ensure good sealing and no leakage.

Tighten the bolts evenly to the specified torque (usually 25-35 N·m) to prevent cylinder body deformation, which could affect sealing performance.

Maintenance Recommendations: Every 2000 working hours, check the wear of the contact surfaces between the cylinder body and the distributor plate, and measure the wear of the plunger bore inner diameter. When the wear exceeds 0.05 mm, replace the cylinder body promptly to avoid a decrease in volumetric efficiency.

Regularly change the hydraulic oil and filter element to prevent oil contamination from causing accelerated wear of the cylinder and plunger. The cleanliness of the hydraulic oil must reach NAS 8 or above.