Servicing magnetic coupling -N25-, manufactured by Sanden — VW

The following description deals with the New Beetle. Therefore differences must be considered, if necessary.

Refrigerant circuit need not be opened to service the magnetic coupling. The refrigerant hoses remain connected.

Note:

If for some other reason the refrigerant circuit requires opening, then it is more convenient to service the magnetic coupling on the compressor once it is removed.

Special tools, testers, measuring instruments and auxiliary items required

3212 Two-hole pin wrench

V.A.G 1331 Torque wrench (5...50 Nm)
Commercially available two arm puller, e.g. B. Kukko 20-10 with 100 mm long legs
Commercially available feeler gauge

Perform following work first:

Remove ribbed belt.

=> Repair group 13
Heating, Air conditioning

Unbolt compressor from bracket and secure to body => page
87-43
.

With petrol engine AQY, the right-hand radiator fan must be removed and the power steering vane pump unbolted from its bracket.

Note:

Do not kink or over stress refrigerant hoses.

Hexagon nut
Renew
15 Nm
Loosening and tightening => fig.
1

Coupling disk
Pulling off => fig.
2

Spacer disks
To adjust gap between coupling and belt pulley
Gap: 0.4...0.8 mm
Checking gap => fig.
5

Snap ring
Renew

Installing correctly:
The flat side faces towards compressor

Ensure seated correctly in groove

Belt pulley
With integral bearing (bearing cannot be replaced)
Pulling off and pressing on => fig.
3

Snap ring
Renew

Installing correctly:
The flat side faces towards compressor

Ensure seated correctly in groove

Magnetic windings
Installing => fig.
4

Note:

An overheating protection fuse in installed in the magnet windings. The overheating protection fuse interrupts the voltage supply to the magnet windings as soon as the magnetic coupling is too warm (e.g. stiff/binding compressor).

Bracket
With bolt

Bracket
Bracket
Bolt
Compressor
Threaded sleeve/bush
Drive back before installing compressor

Fig.1
Loosening and tightening hexagon nut

Torque setting 15 Nm

Removing hexagon nut.

Use two-hole pin wrench 3212 to counter support.

Fig.2
Pulling off coupling disk

Release coupling disk carefully with two screwdrivers -A- and take off.

Fig.3
Pulling off and pressing on belt pulley

Remove snap ring =>page
87-55
, item
4
.
Position legs of two arm puller, as illustrated -arrow-, and pull belt pulley off.

Note:

If the legs are positioned on the lower edge of the belt pulley there is a danger that the magnetic coupling -N25- windings may be damaged.

Push belt pulley on by hand, or carefully press belt pulley on (on bearing inner race) using a suitable driver if necessary.

Fig.4
Installing magnet windings

Fit magnet windings onto compressor.
Fit locking pin -C- into cut-out of magnet windings -A-.

Fig.5
Checking gap and adjusting

Gap: 0.4...0.8 mm

Determining dimension "1"

Measure and note dimension between belt pulley -2- and coupling disk -3- using a depth gauge -1-.

Perform 3 measurements 120° offset.

Determining dimension "2"

Switch on ignition and air conditioning system (1st blower speed) or connect connector -4- to vehicle battery using temporary cables.

The magnetic coupling must pull on.

Measure and note dimension between belt pulley -2- and coupling disk -3- using a depth gauge -1-.

Measure at same positions as for "1".

Determine gap.

The gap is calculated from the difference between dimension "1" and dimension "2".

Notes:

The gap must lie within the given tolerance all-round the circumference.
The gap can be measured when the compressor is installed.
If the gap lies outside the permitted range, remove coupling disk and adjust gap by adding or removing spacer disks.