Replacing the compressor pulley (Audi A4 B8)

Note: At the start of production, Densoruna 6 SEU 14 compressors were installed on vehicles with 4-cyl. and 6-cyl. engines. It is possible that later, depending on the engine and production time, compressors from other manufacturers or other designs will also be installed. The compressor on vehicles with 4-cyl. and 6-cyl. TDI engines can be removed and installed without opening the refrigerant lines. For vehicles with a 6-cylinder petrol engine, the compressor can only be removed from the bracket when the air conditioning circuit is open.

Preparatory work when replacing a belt pulley

Turn off the ignition. Remove the sound insulation from the front. Mark the direction of rotation of the poly V-belt. Loosen and remove the poly V-belt. Before removing the poly V-belt, mark the direction of travel with chalk or a felt-tip pen. Changing the direction of a previously used belt may result in its destruction.

Replacing the belt pulley

(version without magnetic clutch)

Note: If the pulley overload protection has been triggered, check the compressor for ease of movement before replacing it. If the compressor is running with difficulty, replace it as an assembly. To remove the belt. there is no need to remove the compressor from the engine to remove the pulley. Depending on the engine variant, it may be necessary to remove the panel from the car and move it forward slightly (to free up some space). Depending on the compressor type and engine model, different pulley models may be installed (various diameters). As a spare part, the belt pulley with driven disk and cap has an individual number. The belt pulley and driven disk are fastened with a bolt (no bolt needed). During manufacturing, a prescribed amount of a certain lubricant is introduced into the thread of the driven disk through this bolt; this volume of lubricant is sufficient for a single installation of the driven disk on the compressor shaft (therefore, the removed slave disk cannot be reused).

Removal the belt pulley from the compressor

Removal the belt pulley from the compressor

Follow the instructions for replacing the belt. pulley "E". Perform preliminary work in the same way as when removing the belt. the pulley is made of plastic and is not impact-resistant, so handle it with extreme care. If the overload protection of the driven disk "C" is triggered, the belt pulley "E" can be turned with the outer part of the driven disk "C" without turning the compressor shaft "B" and the hexagon "D" installed on the driven disk (the inner part of the driven disk "C").



Remove cap "A." Hold compressor drive shaft "B" with, for example, a 7 mm Allen key and turn driven disk "C" with belt pulley "E" in the direction of the arrow. Compressor drive torque is transmitted to the compressor shaft through the bolted connection of driven disk "C" to the compressor shaft. If, during operation of the compressor, the driven disk "C" has become so tightly screwed onto the compressor shaft that it cannot be removed (a 7.5mm "B" Allen key may not transmit the required tightening torque), the compressor must be replaced. Remove driven disk "C". Remove retaining ring "A". Remove belt pulley "B".

Installation

Replace retaining ring "A." Clean the compressor flange before installing pulley "B." When installing retaining ring "A," ensure that the ring is not bent more than necessary. Install the belt pulley "B". Insert the snap ring "A" with the correct side, the beveled side "C" facing away from the compressor (the flat side faces the compressor). Clean the compressor shaft threads. The threads of the new driven disk are already lubricated with the prescribed amount of a specific lubricant during production. To install the driven disk, lightly lubricate the rubber elements "D", for example with tire paste or soap solution (antifriction agent). Insert rubber elements "D" into belt pulley "B" as shown in the figure. Place the rubber element of driven disk "C" onto belt pulley "E" so that driven disk "C" is positioned against the thread of compressor shaft "B." Screw driven disk "C" onto compressor shaft "B" by turning it counterclockwise (arrow). Hold the compressor drive shaft "B" with, for example, a 7 mm Allen key and turn the driven disc "C" with the belt pulley "E" counterclockwise "arrow" (tightening torque 30 Nm).

Replacing the belt pulley with the magnetic clutch "N25"

Note: If the pulley overload protection has been triggered, check the compressor for ease of movement before replacing it. If the compressor is running with difficulty, replace it as an assembly. To remove the belt. there is no need to remove the compressor from the engine to remove the pulley. Depending on the engine variant, it may be necessary to remove the panel from the car and move it forward slightly (to free up some space). Depending on the compressor type and engine model, different pulley models may be installed (various diameters). As a spare part, you can get a belt pulley with a magnetic clutch using the part number. The belt pulley and driven disk are fastened with a bolt (the bolt is not needed and is disposed of). During manufacturing, a prescribed amount of a certain lubricant is introduced into the thread of the driven disk through this bolt; this volume of lubricant is sufficient for a single installation of the driven disk on the compressor shaft (therefore, the removed slave disk cannot be reused).

Removal and installation the clutch disc

Turn off the ignition. Perform preparatory work when replacing the belt. pulley. Remove the cap "A". Hold the compressor drive shaft "B" with, for example, a 7 mm Allen key and turn the clutch disc "C" in the direction of the arrow. The compressor drive torque is transmitted to the compressor shaft through the bolted connection of the clutch disc "C" to the compressor shaft. If, during operation of the compressor, the clutch disc "B" has become so tightly screwed onto the compressor shaft that it cannot be removed (a 7 "A" Allen key may not be able to apply the required tightening torque), the compressor must be replaced.

Checking the clearance between the belt pulley and the clutch disc

The gap must be within the acceptable range around the entire perimeter of the disc. The gap size can also be measured with the compressor installed. If the clearance value is outside the permissible range, remove the clutch disc and adjust the clearance value by removing or installing spacer washers. Turn off the ignition. Perform preparatory work when replacing the belt. pulley. Clutch disc "C" is tightened to the required torque. tightening torque (30 Nm) on the compressor shaft "E". Using template "F", measure the distance 1 between the belt pulley "B" and the clutch disc "C" at 3 points around the perimeter of the clutch disc "C" (record the measured value). Apply 12 V to the first connector "A". Apply ground to the compressor housing "D". Using template "F", measure the distance 2 between the belt pulley "B" and the clutch disc "C" at 3 points around the perimeter of the clutch disc "C" (record the measured value). Calculate the gap size based on the measured values (sizes 1 and 2). Specified gap value: 0.4...0.6 mm (up to 0.8 mm for a used magnetic coupling).