Blower Motor Restoration

[440]

Here is a blower motor restoration. I didn't intend to restore this motor yet but as a spin off from my other thread I ended up doing it anyways.

Firstly you need to clean the output shaft so it is squeaky clean, use WD40 and a razor blade to clean off any crud (you'll thank me later). Next undo the 2 nuts on the end of the motor, remove these and carefully split the case in half, do not force it or you'll ruin it. Inside you should see the armature and brush plate. We need to carefully remove the brush plate in order to get the armature out.

To do this carefully bend the 4 tangs that secure the brush plate. Before completely removing the brush plate you'll need to hold the brushes back to prevent from damaging the phenolic washer on the armature. Bend some wire to retain the brushes and gently slide it off. Once clear of the phenolic washer you'll have to release the brushes to completely remove the plate

[440]

Once the plate is removed gently pull the armature out of the case. If it does not come out by gently pulling on and wiggling it stop and clean the output shaft better. Whatever you do DO NOT press on the shaft to try and force it, you can damage the motor. This is where I ruined my first motor. If you pop the spherical brass bushing out the motor is pretty much ruined. I tried popping it back in with no luck and broke the fingers that hold it in place.  

Now that you have the armature out count the washers on each end of the arm, remove and clean everything really well, I like to use an electric contact cleaner and a stiff bristle tooth brush. A clean motor is a happy motor. Be careful not to over saturated the factory paper as you don't want to ruin it.

Once everything is clean polish the armature shaft where the bushings ride on it. Make sure you also polish the inside of the spherical bushings, you don't have to go crazy on them.

Now it's time to clean the comm. You'll notice the comm has a dark burnt ring where the brushes make contact. We want to get rid of this.

Preffered Method #1 is to use a lathe to cut and true the comm. Make very light cuts till the com is true and all pitting is removed. Run a ball point pen along the grooves between the copper segments to deburr the edges.

Method #2, if you don't have or know anyone with a lathe securely mount a drill and chuck the armature into it with the comm closest to the chuck. Using a flat 1/4" wide piece of wood or so wrap fine sandpaper around it and with the drill running lighty sand the comm. Keep it as flat as you can and work back and forth till the pitting is gone. Run a ball point pen along the edges between the copper comm segments to deburr them

[440]

Using the same grade sandpaper wrap it around a pencil and lightly sand the face of the brushes to remove any scoring. Also give the brush sides a light sand to remove any tarnish, same with the insides of the brush hoods.

Give everything a final clean and let dry. Stack the shims back on the armature. The bushings are self oiling but I like to grease them anyways. Slide the armature back into the case taking care not to lose the shims. Re-install the brush plate the same way you removed it taking care not to damage the phenolic washer. Bend the tangs back and spin the motor by hand. Make sure the brush wires have enough slack so they don't hang up as they wear. If everything is good put the top half of the case on with the vent hole and wires in the correct location and secure it. Spin the motor one last time by hand to check it. Connect the motor to 6v or so and run the motor, it should be smooth as silk.

Primed and all ready for paint !

[440]

With a bit of elbow grease, concentrate dish washing liquid, and a few different brushes - you can make almost any squirrel cage look good again.

[resq302]

great step by step  how to!

[440]

Thanks, I probably should have put it in the electrical section though 

[PlainfieldCharger]

Ruined my first motor, cracked the brush mounting plate Be careful. If this was posted sooner... :icon_smile_big:Great write up 440

[bakerhillpins]

Sweet!!!

Thanks   

[Bob T]

Great how -to 440  , will be bookmarking this.

I'll add if you dont mind -  run a stanley knife between the segments on the comm to make sure they are clean and clear and then the ballpoint pen trick
Possibly measure the brushes against a known length and assess for replacement, just so hard to replace them later on , easier to do it when its apart. Most local electric ( industrial ) motor rewinder/repair companies have the contacts for making up brushes, or could supply something to fit e.g. small electrical appliance drill or grinder, we've had a few made/supplied for different machines at work

[boydsdodge]

Do you need to lube these motors? Light oil/grease?

[1974dodgecharger]

Well I feel like a dumb ass I threw my original away....