Heater Fan Motor Demystified

Heating / Cooling / AC

  1. Dana67Dart

    Dana67Dart Like a fine wine, only getting better with age! FABO Gold Member

    Messages:
    4,417
    Likes Received:
    2690
    Joined:
    Jul 16, 2017
    Location:
    Northern Colorado
    Local Time:
    10:44 AM
    I needed to see if I could get my fan motor rebuilt. Most DC motors are fairly simple so I decided to disassemble one to see what is repairable / replaceable by me.

    This motor says it is from a 68 A-Body

    A markings on the side read:
    12V 15290-01
    2837678 1558

    build date??? 1558 155th day of 68????

    Fan fully assembled
    IMG_20200602_165407.jpg

    IMG_20200602_165434.jpg

    IMG_20200602_165448.jpg

    IMG_20200602_165520.jpg

    Loosen set screw and the fan came right off

    IMG_20200602_165611.jpg

    2 nuts and the mounting plate comes off. Note orientation.

    IMG_20200602_165827.jpg

    There is a cardboard gasket of sorts that comes off next.
    IMG_20200602_165852.jpg
    IMG_20200602_165949.jpg

    Remove 2 more nuts and the bolts that hold the 2 halves together.
    IMG_20200602_170008.jpg

    IMG_20200602_170722.jpg

    Continued...
     
    Last edited: Jun 2, 2020
    • Like Like x 1
    • Thanks! Thanks! x 1
    • Dana67Dart

      Dana67Dart Like a fine wine, only getting better with age! FABO Gold Member

      Messages:
      4,417
      Likes Received:
      2690
      Joined:
      Jul 16, 2017
      Location:
      Northern Colorado
      Local Time:
      10:44 AM
      Part 2...
      Seperating the 2 halves.
      Due to where the wire insulator is, it needs to be released before the halves are separted.

      Carefully press in a dull screwdriver while rocking the insulator to the side and in.
      IMG_20200602_171851.jpg
      Alternately rocking the shaft side half allowed the halves to be seperated. Go slow you don't want to damage any wires.
      IMG_20200602_171047.jpg

      IMG_20200602_171112.jpg

      The shaft half off, a little steel wool on the shaft will help it come off easier

      IMG_20200602_172054.jpg

      There is a small plastic washer, don't lose it.
      IMG_20200602_172118.jpg

      Here is a shot of the fiber board that holds the brushes. Note the 4 twisted retainers
      IMG_20200602_172144.jpg
      IMG_20200602_172240.jpg

      Brush plate removed, don't lose the springs.
      IMG_20200602_172408.jpg

      To remove the armature, I had to move one of the wires that are crimped to the brushes out of the way a little
      IMG_20200602_172421.jpg

      Armature came out no problem, the short shaft end has 2 plastic washers
      IMG_20200602_172519.jpg

      Cont...
       
      Last edited: Jun 2, 2020
      • Like Like x 1
      • Thanks! Thanks! x 1
      • Dana67Dart

        Dana67Dart Like a fine wine, only getting better with age! FABO Gold Member

        Messages:
        4,417
        Likes Received:
        2690
        Joined:
        Jul 16, 2017
        Location:
        Northern Colorado
        Local Time:
        10:44 AM
        Part 3...
        Looking down inside the lower half you can see the bearing and the windings. Everything looked good so I reassembled the motor, put a little lube on the bearing surfaces. The motor spins more freely now.

        IMG_20200602_172532.jpg

        It looks like if the bushings are worn out, the 3 rivets would need the be removed, and the bearing retainer removed and replaced.

        I suspect the windings can be removed as well, there are some positive stops on the side, but I did not want to do any damage to the motor so I did not try. A professional shop would have the proper tools and presses to do that.

        From what I saw there is not much I could replace myself, the brushes, cleaning, polishing, and lubing would be about it.

        Hooked the fan up to the car battery.
        When it first started it pulled 4.1 amps but slowly sped up and finally got to 3.2 amps. The lube on the bushings probably got spread and the bushings may have heated up and expanded a bit.

        I was able to confirm a long held belief that a fan cavitating draws less current than when it's moving air, and a baffle in front of the inlet to the fan, even 2 inches away reduces it's output noticibly
         
        Last edited: Jun 2, 2020
        • Like Like x 2
        • Thanks! Thanks! x 1
        • moparmat2000

          moparmat2000 FABO Gold Member FABO Gold Member

          Messages:
          16,160
          Likes Received:
          5355
          Joined:
          May 13, 2010
          Location:
          Grand Tetons
          Local Time:
          11:44 AM
          You can also chuck the armature into a drill and with very fine sandpaper like 400 grit on a flat stick you can polish the commutator smooth.
           
          • Like Like x 1
          • KitCarlson

            KitCarlson Well-Known Member

            Messages:
            2,511
            Likes Received:
            398
            Joined:
            Jan 17, 2008
            Location:
            Middle Tennessee
            Local Time:
            11:44 AM
            The patina on the commutator is fine. Removing it, will lead to brush wear again. Commutator patina is essential for less brush mechanical resistance and long brush life.
             
            • Thanks! Thanks! x 1
            1. This site uses cookies to help personalize content, tailor your experience and to keep you logged in if you register.
              By continuing to use this site, you are consenting to our use of cookies.