Trico Vacuum Fan Repair

This one came off of a 1948 CJ2A that came from New York State - a Jeep know as Old Blue (Ric Megley, Sr's - parts Jeep that was to good to part out).

 

I could not find any repair posts here or in other web searches.  So, here is what I did go get this fan working again.

How this fan works:  The fan is attached to the vacuum line that provides vacuum to the Trico Windshield Wiper.  The fan has a needle valve that is opened by the driver to control the on/off and speed of the fan.   There is a small vent on the side of the fan that air is drawn into.  That air pushes on an impeller that is attached to the fan.  The fan rotates counter clockwise.

The problem with doing repairs to this fan is that it was assembled at the factory with no means of disassembly.  The fan body is pot metal and the back of the fan has a metal plate that was forced in like a freeze plug.  So, it has to be repaired without opening the fan motor.

The fan I am working on probably has not been run for 60 years.  The blade is stuck, bug nest in the vacuum line whole.  On/ Off valve is stuck.  Base swivel is stuck.

Don't attempt of repair a fan if you are in a hurry, you will most probably end up damaging it.

1. Remove the bug nest from the fan vacuum fitting with a long needle.  Get it all out.  If the needle valve is closed, you could use compressed air after using the needle.

Step two: Apply Sewing machine oil to these areas:

1.  The seal where the main shaft enters the motor behind the fan blade.

2.  The valve stem and spring of the On/Off Valve

3.  The base swivel in the pot metal casting.  There are two mating surfaces one on the swivel ball and one where that casting meets the lower casting that (with the needle valve).

4.  The intake hole on the side of the fan motor where air is pulled into the motor.  

Let the fan sit for an hour.   Then re-apply oil to each of the areas in step two.

1. With a small drill bit or carbonator jet reamer gently clear any obstructions from the air inlet hole on the side of the vacuum motor.  Don't enlarge this whole.  Just gently clear the hole.

2. Gently turn the needle valve, add oil to it as it is removed.  Completely remove the valve and clean it with a oiled cloth. Clean the valve seat  (Q-tip with oil can be used here).  Reinstall the the needle valve and leave it open 3 turns.  

3.  Add more oil to:  The seal where the main shaft enters the motor behind the fan blade. 

4. Attach a section of vacuum line to the vacuum port on the fan.  Blow into the line to force any obstructions in the fan inlet hole out.

1. Take the sewing machine oiler (show above) and put it against the air inlet hole and force sewing machine oil into the fan.  I actually pulled a vacuum (sucked) on the vacuum line as I forced oil into the the fan motor.  Put a good amount of oil in the fan motor.   Now, add more oil because it really needs a lot of oil in the fan motor to lube the bearing that have not been lubed since it was assembled at the factory 80 years ago.

2.  Add more oil to :  The seal where the main shaft enters the motor behind the fan blade. 

3.  Place the fan on it's front, blade side down (so the oil runs to the bearing behind the front seal).

Let the fan sit over night.

1. Take a pencil and move the fan blade about 1/2" Counter Clockwise and then back to the starting position.  Do this serval times until it begins the free up.   Add more oil to :  The seal where the main shaft enters the motor behind the fan blade. Then repeat this process increasing the range of motion until the van blade will rotate 360 degrees.  Add more oil to :  The seal where the main shaft enters the motor behind the fan blade. 

2.  Move the blade with the pencil until it will move some what freely with each push of the pencil.  Stay at it, this takes time.

1. Blow into the vacuum line while holding the fan so that the air inlet on the side of the fan is down.  This will force the dirty oil out of the fan (a paper towel can be used to catch the mess).  Get as much out as you possibly can.

2. Put clean oil back into the motor as describe above (step 4.1).

Step Seven:

1. Set your air compressor to about 80 PSI with the shop cleaning spray nozzle on it.  Aim the nozzle the fan blade and force it to turn Clockwise.   This will take a few tries to get the angle correct for the nozzle to push the blade.  Mine would only move to about 180 degrees but within 30 or so attempts, it would rotate 360 degrees and finally would spin wide open with the air from the nozzle.

2. Repeat step 7.1 going Counter Clock wise.  Stay at it.  This side is more difficult to get the fan to cycle due to the pitch of the blade.  But it will free up and spin wide open.  

(note: oil will start to come out of the vacuum line at some point due to all of this turning)

Step Eight:

1. Take the air compressor nozzle and put it up against the air inlet on the side of the motor casting and force air into the motor.  You will need to get the angle correct but the fan should spin and some amount of oil will come out of the vacuum line.  The fan should spin freely and fast as you very the amount of air you put into the fan.  Run the fan for a while to make sure it if completely freed up.

Step Nine:

1. Attach it to a vacuum line and it should work as designed.