Cross section through pulley with electromagnetic coupling

The pressure difference ensures that R 134 A in its gaseous state opens inlet valve and fills the cylinder. As soon as the piston begins to approach the cylinder head, the inlet valve closes and R 134 A is compressed until its pressure brings about opening of exhaust valve (delivery). The R 134 A at 9.81 - 19.6 bar (10 - 20 kg/cm²) and 80° - 100°C may then move along the line leading to the condenser.

The pulley and electromagnetic coupling assembly shown in the figure is fitted to the shaft and compressor front cover.

Cross section through pulley with electromagnetic coupling

1. Disc fitted to compressor shaft by means of key
2. Compressor front mount
3. Rotor and pulley unit
4. Solenoids
5. Ball bearing
6. Compressor shaft
7. Gasket

When the air conditioning system is not working, the pulley turns freely on its bearings because it is continually turned by the pulley belt fitted to the crankshaft.

When the air conditioning system is activated, the solenoid attracts disc (1) on the pulley, which becomes joined to the compressor shaft and causes it to turn.

DISASSEMBLY

This type of compressor cannot be fully dismantled, but only partly disassembled in order to replace parts 1 - 3 - 4 - 5 - 7 shown in the first figure and the regulation valve. The various operations required are listed and described in order on this page and in the following pages.

Position mount 1877506000 (shown shaded) in the vice and fasten compressor by means of two bolts.

Use tool 1877507000 (shaded) to hold the clutch plate in place and unscrew the nut holding it to the compressor shaft.