55A alternator brush replacement.

Discussion in 'How To' started by mikedjames, Jul 28, 2013.

  1. mikedjames

    mikedjames Supporter

    Using an original 55A alternator with external regulator. Symptom was that the alternator warning light would stay on for about 30 seconds to a minute after starting the engine then go off.

    I just half took my engine apart to release the alternator.
    Then I found that the three screws fixing the regulator connection were all you need to get at the brushes.
    The rrgulator connector has three tags that mate with the plug with the field and warning light connection.
    . The brush holder was covered in black paste the result of leaked oil and the dust from rthe brushes. The slip rings were also black and slightly worn. These were easier to see with the alteenator out.

    The brushes are 8mm by 5mm. I bought the 6mm by 3mm variety. They can be bodged in but it will need replacing but they will get you running.

    The wires on my new brushes had thin rigid wires welded on the end of the braided section. These are used to help thread the wires through the holder.

    Take out the old brushes the wire connecting the brush to the holder is soldered to the outer little loop and the inner loop is lightly squeezed over the braided wire and the silicone insulation tube.

    Keep the old springs and thread them onto the new brushes. When fitting the new brushes they should be pushed down by the springs until about 10mm remains in the holder. This means they dont fall over as you assemble the holder onto the alternator. This is also the position at the end of brush life.
    When its new the springs will be compressed and the wire will be loose.

    Clean the slip rings using emery cloth. Easier with the alternator out. Wet and dry paper falls apart and is a pain.

    When you put it back there is a spring loaded tag inside the alternator that will push the connector toward the fan as wwell as the springs on the brushes.
     

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