Checking andor adjusting alternator fan wheel and air conditioning compressor drive belts

Caution: Make sure the ignition key is pulled off whenever measurements are made.

Checking used drive belts (alternator and fan wheel)

Use belt tension measuring instrument (Special Tool 9574) to check tension.

A description of how to use the Special Tool is contained in Repair Group 13, page 13-30.

Retensioning the belt is only required if the belt tension displayed at the measuring instrument is less than 15 scale increments when the engine is cold and less than 20 scale increments when the engine is hot.

Retensioning the belts

Retension belts as described in the General Adjustment Notes section. Before measuring the belt tension, start engine and let engine idle briefly.


Cold engine: 15 to 23 scale increments

Engine at operating temperature: 20 to 28 scale increments

Fitting a new belt (alternator and fan wheel)

When fitting a new belt, be sure to observe the correct assembly sequence in order to avoid any loss of belt tension during vehicle operation.

1. Fit new belt. Adjust tension by inserting or removing shims as required.

Shims are available for belt tensioning in thicknesses of 0.5 mm and 0.7 mm. The 0.7 mm shim is identified by a 2 mm dia. drill hole.

2. Before measuring the belt tension, start engine once more and run engine at idle briefly.


Cold engine: 23 to 35 scale increments

3. Run engine at idle for approx. 15 minutes or test drive vehicle for approx. 10 miles. Check tension again. Specification: 28 to 40 scale increments

Retension if required.

Test requirement: Engine at operating temperature

Adjustment specifications for A/C compressor drive belt

Specification: 30 to 35 scale increments Retension if required.

General adjustment notes

Fan wheel and alternator have separate drives.

4. Use only V-belts that have been approved by the manufacturer.


Rotate engine only at lower belt pulley or by operating the starter. After completing all operations, check to make sure that hexagon head nut has been tightened sufficiently on alternator shaft.


1 = Alternator drive components

2 = Fan wheel drive components

Adjusting the V-belts

1. Use polygon wrench (999 571 052 02)

to lock shaft and undo hexagon head nut. Remove shims and pulley half.

2. If belt tension is below specification, remove one shim from between pulley halves and refit in front of front pulley half.

Tighten hexagon head nut to 50 ± 5 Nm.

3. Three additional M 6 screws have to be undone for V-belt and fan wheel.

V-belts for the power steering pump:

Check condition

1. Remove the engine guard.

2. Undo the final-muffler bracket and remove from the final muffler and engine. Remove the left-hand top engine cover panel and the toothed-belt guard.


3. Check the toothed belt for wear and damage by cranking the engine. The belt tension is not adjustable.

Replacing the spark plugs for the upper ignition circuit

1. Remove the heating blower

2. Remove the air-filter cover and filter insert

Replacing the spark plugs for the lower ignition circuit

1. On vehicles with catalytic converter, separate the plug connection for the Lambda probe, removing the hot-air blower beforehand.

2. Push the probe cable with rubber grommet downwards through the left-hand side engine paneling.

3. Remove the exhaust system complete (separating point downstream of catalytic converter)

4. Remove the side engine encapsulation panels.


1. Do not use any lubricant on the plug thread.

2. With spark plugs which are difficult to remove, use Special Tool (disassembly clamp) 9513, order no. 000.721.951.30

Replacing spark plugs:

Unscrew spark plugs with standard commercially available socket wrench insert form Mes-sers. Snap-on Order Nr. S 97 06 and extension Snap-on, Order No. FXW4.

Visual inspection for leaks: Oils, fluids

This check can be carried out after the engine guard has been removed.

Crankcase ventilation

Check that all hose connections are securely fitted

Air filter:

Replacing the filter insert

1. Release the retaining clips and remove the housing cover with filter insert.

2. Take out the filter insert and clean the inside of the filter housing with a non-fibrous cloth.

3. Install a new filter insert. (Fins in horizontal position).

Fuel system:

Visual inspection for leaks, damage, free flow and secure fitting of the line connections

Intake air guide:

Check that hoses, lines and connections are fitted securely


Check that the hose connections are fitted securely through-out the entire intake system

Parking brake:

Check the free movement of the parking-brake lever

The parking brake is fitted with asbestos-free brake pads. This type of parking brake must never be adjusted in such a way that the brake pad has to "grind itself free" in operation.

If it is possible to raise the lever by more than 4 notches, using average force, without any sign of a braking effect, the parking brake needs adjustment.

Adjusting the parking brake:

1. Remove the rear wheel.

2. Release the parking brake and push the disk-brake pads on rear wheels back until the brake disk can be turned freely.

3. Undo the adjusting nuts on the turnbuckle (arrow) until the cable is slack.


Remove the tray behind the brake lever (2 fastening screws) to gain access to the turnbuckle.


4. Insert a screwdriver through the hole in the brake disk and turn the adjusting device until the wheel is locked. Then undo the adjusting device again until the wheel can be turned freely, then undo by a further

2 notches.

5. Pull up the brake lever by 2 notches and turn the adjusting nut on the turnbuckle until both wheels can still just be turned by hand.

6. Release the parking brake and check whether both wheels turn freely.

Foot brake:

Check the play in the brake pedal

The brake pedal has no stop. As the brake pedal has no support facility in the initial position if the brake push-rod is adjusted correctly, the permanently set air play in the brake unit is guaranteed. If the brake pedal plate is pushed down by hand, you can feel a push rod play of approx. 8 mm.

If the push rod is adjusted at the swivel head (3), this alters the position of the brake pedal. In this case, you must also check the setting for the stop-lamp switch.

The push rod is correctly adjusted if the plate of the brake pedal is approximately level (±3 mm with the plate on the clutch pedal.(Clutch pedal in initial position).

Check the setting for the stop-lamp switch

The stop lamp must light up after the brake pedal has travelled 6-16 mm (measured at middle of the pedal brake).

If the stop lamp lights up with less than 6 mm travel, turn the stop-lamp switch (2) to the right until it responds within the toleran-cerange. (Do not damage electric cables and connectors). If the adjusting range of the stop-lamp switch is inadequate, adjust the brake pedal with the swivel head on the push rod (shorten the push rod).

If the stop-lamp switch lights up after 16 mm travel, adjust the brake pedal with the swivel head on the push rod, (lengthen the push rod) until the stop lamp switch responds within the tolerance range.


Check the brake-fluid level

1. With the ignition switched on, pump the brake pedal repeatedly until the electric motor in the pump unit can be heard to start.


The pump unit is located at the front of the luggage compartment and supplies the brake booster and the valve block for the differential lock (interaxle and wheel-to-wheel) via a diaphragm pressure accumulator.


2. Once the pump unit has switched off, the brake-fluid level must be between the min. and max. markings on the reservoir. Never fill to above the max. marking as brake fluid may be discharged through the vent line. Only use brake fluid DOT 3 or DOT 4 (SAE J 1703).

Brake system:

Visual inspection, checking the brake pads and brake disks for wear


Brake pads must be replaced for the complete axle when the brake- pad warning lamp lights up, but at the latest when the pads have worn down to 2 mm. If the brake-pad wear is indicated by the warning lamp, the warning contact (sensor including cable and connector) must also be replaced. It is possible to avoid replacing the warning contact if the brake pads are replaced when worn down to 2.5 mm at the latest. Warning contacts must be replaced if the core of the cable has been exposed. If only the plastic part of the warning contacts has been rubbed, however, it is not necessary to replace it.

1. Remove the wheels to check the brake pads.

2. Check the brake pads for wear by means of a visual inspection.

The wear limit has been reached when the brake pad is worn down to 2 mm.

0 0

Post a comment