Pic. 12.4. The electromagnetic clutch of the compressor drive: 1 - the elastic element of the disk; 2 - clutch pressure disc; 3 - clutch driven disk; 4 - bearing; 5 - inner race of the bearing; 6 - working surface of the pulley; 7 - pulley streams; 8 – electromagnet winding; 9 - body of the electromagnet; 10 - electrical connector block.
The air conditioner compressor is a complex, high-tech unit. Many compressor pumping units are manufactured using selective assembly. Therefore, manufacturers do not supply components for the repair of the pump part of compressors for retail sale. The only repairable compressor unit in garage conditions is the electromagnetic drive clutch (pic. 12.4).
When operating a car, compressor clutch failure is a very common malfunction. As a rule, the bearing 4 of the pulley begins to collapse first.
The cause may be incorrect tension of the drive belt, water ingress when driving through a deep puddle, slippage of the pressure plate and, consequently, overheating of the bearing, etc. As the problem grows, backlash begins to appear.
When the backlash reaches a critical value, the inner surface of the pulley during rotation begins to rub against the surface of the body 9 of the electromagnet coil. As a result of friction, the parts heat up, and the insulation of the winding 8 of the coil begins to burn out. An electrical short occurs and the electromagnet fails.
In the most advanced cases, the bearing jams and the inner race 5 of the bearing rotates on the landing neck of the compressor cover. After that, the compressor has to be replaced, and this is a very expensive repair at specialized services.
In order not to expose yourself to unnecessary expenses, during routine inspections of the car, pay attention to uncharacteristic noises during the operation of the air conditioning compressor. If you suspect a problem with the pulley bearing, remove the drive belt (refer to Inspection and Replacement of the Accessory Drive Belt) and turn the pulley by hand. The bearing should rotate evenly, silently, without jamming. There must be no axial and radial play.
If necessary, replace the bearing without waiting for its complete destruction.
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