PLATE-CATERPILLAR 4P6445 - Caterpillar

General
The following disassembly and assembly procedure is presented for reference purposes and presupposes that a major rebuild of the compressor is being undertaken. Several maintenance kits are available which do not require full disassembly. When servicing this compressor with a maintenance kit all components contained in the kit must be used. The instructions provided with these parts and kits should be followed in lieu of the instructions presented here.Removal
These instructions are general and are intended to be a guide, in some cases additional preparations and precautions are necessary.1. Block the wheels of the vehicle and drain the air pressure from all the reservoirs in the system.2. Drain the engine cooling system and the cylinder head of the compressor. Identify and disconnect all air, water and oil lines leading to the compressor.3. Remove the governor and any supporting brackets attached to the compressor and note their positions on the compressor to aid in reassembly.4. Remove the discharge and inlet fittings, if applicable, and note their position on the compressor to aid in reassembly.5. Remove the flange or base mounting bolts and remove the compressor from the vehicle.6. Remove the drive gear(s) or pulley from the compressor crankshaft using a gear puller. Inspect the pulley or gear and associated parts for visible wear or damage. Since these parts are precision fitted, they must be replaced if they are worn or damaged.Preparation For Disassembly
Remove road dirt and grease from the exterior of the compressor with a cleaning solvent. Before the compressor is disassembled, the following items should be marked to show their relationship when the compressor is assembled. Mark the rear end cover in relation to the crankcase. Mark the base plate or base adapter in relation to the crankcase.A convenient method to indicate the above relationships is to use a metal scribe to mark the parts with numbers or lines. Do not use marking methods such as chalk that can be wiped off or obliterated during rebuilding.Cylinder Head
Remove six cylinder head cap screws (1) and tap the head with a soft mallet to break the gasket seal. Remove unloader cover plate cap screws (2), lockwashers (3) and unloader cover plate (4). Scrape off any gasket material (5) from the cover plate, cylinder head and crankcase.1. Remove unloader pistons (7), O-rings (6) and springs (8).2. Inspect unloader piston bushings (9) for nicks, wear, corrosion and scoring. It is recommended that the compressor be replaced if it is determined that the unloader bushing is damaged or worn excessively.Before disassembling the discharge valve mechanism, measure and record the discharge valve travel (from closed to completely open).3. If the measured discharge valve travel EXCEEDS 11.68 mm (.046 in), the compressor should be replaced. If the discharge valve travel does not exceed 11.68 mm (.046 in), using a 9/16 inch hex wrench, remove discharge valve seats (18), valves (17) and valve springs (16).4. Remove inlet valve stops (14), valves (17), valve seats (11), valve springs (12) and gaskets (10). It is recommended that a tool