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422 Combustion fan rebuild


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  • 422 Combustion fan rebuild

    I took the combustion fan assembly out of my 422 today. I don't see how it comes apart. There is a plastic blade on the side that goes into the heater. It looks pressed on. Looking through the plastic fan cover, I don't see anything that comes off. I have seen reports of a reverse thread nut but I'm not seeing it. How do I disassemble this to get the motor off? I searched the forums but didn't see anything detailed.

  • #2
    I don't know about replacing the bearing in the combustion fan, but some of the earlier 422's had sinister bearings in both the circulation and combustion fan and have a black plug that can be removed to add a couple drops of oil. My 422 has sinister bearings and I didn't know they could be oiled until 2012 when I did my chamber rebuild. I oiled them at that time. Since it's been 5 years since I did the rebuild I guess when spring comes and I'm not using the heater I should disassemble it and oil them again.
    Last edited by FordMan59; 02-27-2017, 06:45 PM.


    • #3
      I found a set screw on the metal fan blade inside the plastic case. I removed it with an allen wrench. The blade won't come off though. Any ideas?


      • #4
        Any way to get a small 2 or 3 jaw puller on it? Maybe spray it with penetrating oil and let it sit for a day or two. Been 5 years since I had my heater disassembled and oiled the bearings in mine so I don't remember much about how the combustion fan/blade is set up. I was thinking the combustion fan blade on my 422 was made out of plastic, but I may be mistaken.


        • #5
          The large blade under the plastic case is metal. I'm going to try and use my heat gun and see if that works. There is a small plastic blade on the other side of the fan inside the heater that I think just ventilates the inside of the unit.


          • #6
            I've never used this product, but here's another possible alternative to heat. Freeze-Off Super Penetrant 11.5 oz. - CRC05002 I know this product is available at my local Auto Zone and is probably available at other auto parts chains.


            • #7
              What you have is corrosion caused by dissimilar metals coming into contact with each other, the fan under the plastic cover is aluminum and the shaft it is on is steel. Add a little moisture and you will get corrosion.
              Loosen the set screw on the aluminum fan and hit the area with the set screw with a little heat and some penetrating oil. It will come off, it just may need a little help if it has never been removed. Once you get it off and get it down to just the motor, if the bearing caps do not have little black plugs in them, take the bearing caps off the bearings, you will see there are very small C clips on the shaft behind the bearings that act as bearing stops be very careful not to damage or loose them when you remove the bearings. Be sure to use a little Loctite on the new bearings to help lock them into place on the shaft. I would also put a bit of antiseze on the shaft when I put the aluminum fan under the plastic cover back on.
              Last edited by OnTheEdge; 03-02-2017, 01:16 PM.