Checking and replacing the brushes and voltage regulator on ZMZ-405, ZMZ-406 engines:
Engines of the ZMZ-406 and ZMZ-405 families are equipped with 9422.3701 or 5122.3771 alternators with built-in integrated voltage regulators.
Checking the voltage regulator
To confirm a voltage regulator fault – switch off all consumers except the side lights and measure the voltage at 1000-1200 rpm–1, which should be between 13.5 and 14.2 V.
Connect a 12 V test lamp to the brushes.
Apply 12 V «+» to the terminal and «-» to the brush holder ground.
The test lamp should light up.
If the test lamp does not light up, the voltage regulator must be replaced.
Replacing the voltage regulator of alternator 9422.3701 or 5122.3771
The voltage regulator is integrated with the brush holder in a single housing.
Disconnect the battery.
Disconnect the wires from the alternator terminals, remove the plug from the alternator terminal.
Using a 10 mm spanner, unscrew the nut.
Remove the capacitor wire terminals from the «+» terminal of the alternator.
Using an 8 mm spanner, unscrew the capacitor mounting nut.
Remove the capacitor.
Using an 8 mm socket, unscrew the two nuts securing the plastic cover of the alternator.
Remove the cover.
Remove the connector from the voltage regulator terminal.
Using a short screwdriver, unscrew the two screws securing the regulator to the alternator.
Remove the voltage regulator with brush holder.
Install the new regulator in reverse order.
Checking the brushes and brush holder
Check the protrusion «a» of the brushes from the brush holder.
If the brush protrusion «a» in the free state is less than 4.5 mm, replace the brush holder with voltage regulator.
Replace the brush holder with worn brushes as an assembly.
Checking and replacing the brushes and voltage regulator with ZMZ-402 type engine
Vehicles with ZMZ-4025 and ZMZ-4026 engines are equipped with 16.3701 or 191.3701 alternators, which do not have a built-in voltage regulator.
These alternators operate with an external transistor voltage regulator type 13.3702-01 or 50.3702, which has electronic protection against short circuits in the alternator field winding circuit.
The regulator is installed in the engine compartment and attached to the mudguard with two nuts.
The regulator maintains the battery charging voltage between 13.4 and 14.7 V at an alternator speed of 2800 - 12,000 rpm-1, corresponding to an engine crankshaft speed of 1400 - 6000 rpm-1, with a load of 5 - 40 A and a temperature of -20 to +80 °C.
At the «Ш» and «-» terminals of the regulator, the voltage drop should not exceed 1.6 V with a current of 4 A in the alternator field winding circuit and a temperature of +20 °C.
Before checking the regulator, make sure the alternator belt tension is correct and the regulator has good ground contact (adjust the belt tension and tighten the regulator mounting nuts to the body if necessary).
Do not connect additional electrical consumers to the alternator field winding power circuit, as this will greatly increase the alternator voltage.
1. Before checking the voltage regulator, check the condition of the wires and the reliability of the connections between the alternator, voltage regulator and battery.
Note that the absence of charging current may be caused by the activation of the regulator protection circuit in the event of a short circuit in the alternator field winding circuit.
Once the short circuit is eliminated, the voltage regulator recovers.
2. The voltage regulator can be checked on the vehicle. For this, you need a DC voltmeter with a measuring range of 20 - 30 V and a division value of 0.1 - 0.2 V.
Start the engine and, maintaining the engine crankshaft speed at 1700-2000 rpm-1, turn on the dipped headlights. The charging current according to the ammeter should not exceed 10 A.
If the ammeter shows a charging current above 10 A, turn off the dipped headlights and side lights.
Measure the voltage at the «+» terminal of the battery, it should be 13.9 - 14.6 V at a regulator temperature of +20 °C.
If the voltage differs from these values, the voltage regulator is faulty and needs to be replaced.
Using a 10 mm spanner, unscrew the two regulator mounting bolts. Under each bolt there are ground wire terminals.
Remove and replace the regulator. Install the new regulator in reverse order.
Removing and checking the alternator brushes
Disconnect the battery.
Using a flathead screwdriver, unscrew the two screws securing the brush holder.
Remove the brush holder. Install the new brush holder in reverse order.
Check the ease of movement of the brushes in the brush holder. If the brushes are stuck, remove the two fixing screws and remove the brush holder cover.
Clean the brushes and clean the holes in the brush holder. If you cannot achieve the desired result, replace the brush holder or brushes.
Brushes with chips, cracks or other defects should also be replaced.
Check the protrusion «a» of the brushes from the brush holder in the free state.
If the size «a» is less than 8 mm, replace the brush holder or brushes.
