Fig. 12.4. Air conditioning compressor: 1 - pressure disk; 2 - electromagnet winding; 3 - pulley bearing; 4 - front cover of the case; 5 - tilt washer cage lever; 6 - swash plate thrust roller bearing; 7 - inclined washer; 8 - compressor housing; 9 - connecting rod; 10 - piston; 11 - nut for fastening the regulator valve block and the reed valve block stops; 12 - discharge line nipple; 13 - suction line nipple; 14 - valve block cover; 15 - reed valve block; 16 - block of performance regulator valves; 17, 21 - shaft bearings; 18 - swash plate shaft; 19 - guide stop of inclined washer; 20 - shaft thrust bearing; 22 - shaft seal; 23 - drive pulley
The air conditioner compressor (Fig. 12.4) is a fairly complex, high-tech unit. Some units of the compressor pump section are manufactured using selective assembly. Therefore, companies producing components do not supply parts for repair of the compressor pump section for retail sale. The only compressor unit that can be repaired in a garage is the electromagnetic drive clutch.
When operating a car, compressor clutch failure is a very common malfunction. As a rule, bearing 4 (Fig. 12.5) of the pulley begins to deteriorate first. The cause may be incorrect tension of the drive belt, water getting in when driving through a deep puddle, slipping of the pressure plate 11 and, consequently, overheating of the bearing, etc. As the bearing deteriorates, play in the pulley begins to appear. When the play reaches a critical value, the inner surface of the pulley begins to rub against the surface of the housing 10 of the electromagnet coil during rotation.
Fig. 12.5. Compressor drive electromagnetic clutch: 1 - elastic steel leash; 2 - splined hole of the disc hub; 3 - driven clutch disc; 4 - bearing; 5 - inner bearing race; 6 - working surface of the pulley; 7 - pulley grooves; 8 - electromagnet winding; 9 - electromagnet wiring harness; 10 - electromagnet housing; 11 - clutch pressure plate
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 circuit occurs - the electromagnet fails. In the most advanced cases, the bearing jams and the inner race of the 5 bearing rotates on the landing neck of the front cover of the compressor. After this, the compressor has to be replaced, and this is a very expensive repair at specialized services.
To avoid unnecessary expenses, pay attention to unusual noises when inspecting the car from the air conditioner compressor. If you suspect problems with the pulley bearing, remove the drive belt (see "Replacement of auxiliary drive belts") and turn the pulley by hand. The pulley should rotate on the bearing evenly, silently, without jamming. There should be no axial or radial play.
If necessary, replace the bearing without waiting for it to completely fail.
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