Parameter	Specification
Manufacturer	Caterpillar (CAT)
Part Number	0R-7793
Product Type	Remanufactured Hydraulic Pump
Pump Design	Axial Piston Pump
Displacement Type	Variable Displacement
Pump Configuration	Swash Plate Piston Pump
Application	Main Hydraulic Pump
Hydraulic Circuit	Open Center / Load Sensing Hydraulic System (application dependent)
Compatible Machines	CAT 416C / 426C / 428C / 436C / 438C
Length	14.8 inch (≈376 mm)
Height	11.85 inch (≈301 mm)
Approximate Weight	35–45 kg
Rotation Direction	According to original machine configuration
Drive Type	Direct engine / transmission driven
Warranty Type	Cat Reman warranty support (application dependent)

1. Pump Type and Structure

Variable Displacement Axial Piston Design

The CAT 0R-7793 uses an axial piston design with variable displacement control.

The main working components include:

1. Cylinder Block Assembly

Function:

• Holds piston bores
• Rotates with the drive shaft
• Generates hydraulic flow through piston movement

Technical characteristics:

• Precision-machined piston bores
• High surface hardness
• Low internal leakage design

---

2. Piston and Slipper Assembly

The piston group is responsible for converting mechanical rotation into hydraulic pressure.

Components:

• Pistons
• Slipper shoes
• Retainer plate

Advantages:

• High volumetric efficiency
• Smooth pressure output
• Reduced vibration

---

3. Swash Plate Control System

The swash plate controls piston stroke length.

When the swash plate angle increases:

→ piston movement increases
→ displacement increases
→ hydraulic flow increases

When the angle decreases:

→ piston stroke decreases
→ output flow decreases

This allows the pump to adjust output according to machine demand.

---

4. Valve Plate

The valve plate controls:

• Oil suction
• Oil discharge
• Pressure balance

A damaged valve plate may cause:

• Low pressure
• Excessive leakage
• Pump noise

---

2. Hydraulic Performance Parameters

Displacement

Approximate displacement range:

40–60 cc/rev class

(The exact displacement depends on the original pump configuration and machine hydraulic specification.)

Estimated flow output:

At 2000 rpm:

Approximately:

80–120 L/min

Actual flow depends on:

• Engine speed
• Pump control setting
• Hydraulic system pressure

---

Maximum Operating Pressure

Typical CAT mobile hydraulic piston pump working range:

(Note: Actual pressure depends on machine hydraulic system calibration.)

---

Speed Range

Typical operating speed:

---

Hydraulic Efficiency

Volumetric Efficiency

Approximate:

90–95%

Affected by:

• Internal wear
• Oil viscosity
• Temperature
• Contamination

---

Mechanical Efficiency

Approximate:

90%+

Depends on:

• Bearing condition
• Rotating group wear
• Lubrication condition

---

3. Hydraulic Oil Requirements

Recommended oil:

• Anti-wear hydraulic oil
• Mineral hydraulic fluid

Common viscosity grades:

---

Oil Cleanliness Requirements

For axial piston pumps:

Recommended:

ISO 4406 Class 18/16/13 or better

Poor cleanliness causes:

• Piston scoring
• Valve plate wear
• Servo failure
• Reduced pump life