Disconnect the ground wire from the battery.
Attention: When the battery is disconnected, the information in the electronic memory devices, such as the engine trouble memory or the radio security code memory, is erased. When disconnecting the battery, follow the instructions in section "Removing and installing the battery".
Raise the front of the car.
Unscrew the engine compartment pan and fan frame.
Unscrew the central bolt-plug of the cover of the high pressure fuel pump.
Screw in an adapter instead of a cork (BMW-135330) and a small dial indicator (measuring range 0-3.0 mm) with a copper gasket and tighten a little.
Rotate the crankshaft clockwise towards cylinder 1 top dead center until the indicator needle remains stationary at its lowest point. In this case, the piston of cylinder 1 is at top dead center if both cams corresponding to cylinder 1 on the chain side point upwards. For control, open the oil filler neck and observe the cams.
To crank the engine, engage 4th gear, release the handbrake and move the vehicle. Or pull up the handbrake, put the gearbox in neutral and turn the crankshaft belt pulley with the head of the wrench on the central bolt.
Reset the dial indicator scale.
Unscrew the plug on the motor block.
Turn the crankshaft clockwise until the blocking rod can be inserted (BMW-112300) through the hole in the engine block to the hole in the flywheel at top dead center.
Attention: Do not turn the engine counterclockwise. This leads to incorrect measurement results.
Model 524td: In this position, the dial gauge should read 1.05 + 0.02 mm.
Model 525td/tds: In this position, the dial indicator should read 0.95 + 0.02 mm.
If the measurement result differs from the specified one, adjust the high pressure fuel pump.
Loosen left and right rear bolts 3.
Loosen nuts 1 and 2.
Attention: Loosen the nuts a little to avoid overtightening by the toothed belt.
Turn the high-pressure fuel pump until the set point indicator on the scale is set.
Tighten nuts and bolts in sequence 1 to 4 to 25 Nm.
Check the adjustment again. To do this, first turn the crankshaft back by 90°.
Remove dial gauge.
Screw in the central screw plug with a new copper sealing washer with a tightening torque of 15 Nm.
Attention: Remove the blocking rod, insert the plug.
Connect the wires to the battery.
Start the engine and, if necessary, bleed the air from the fuel injection system.
After a test drive, check the tightness of the central plug screw and, if necessary, tighten it to a maximum of 20 Nm.