Are defroster fan motors able to be lubed on 4104?

[John Z]

I took out the heater core to clean and flush, and i am now wondering if it is worth the effort to remove the fan motors. If i do, can they be lubed, and if so, how do you do it? Cold weather is rapidly approaching and i need more heat up front! TIA, John Z

[roadrunnertex]

You can remove the fan motors Left one is a fun one to remove.
Take them apart and replace the bearings and brushes.
The bearings can be located and bought from any bearing supply.
I re-worked the defroster motors on my P8M4905A Buffalo and it sure made a difference.
Luke at U S Coach has the brushes.
jlv

[JohnEd]

John Z,

You seem to have gotten the inside track advice.  I hear the word bearing but I have only found bushings in generic small motors.  My experience is that brass against steele is its own lube and putting oil on it will lead to howling and vibration as the bushing accelerates to failure.  It always started off like a real fix but ended badly as the oil/grease got harder.  Replace the bearing and also use the proper thickness of thrust washers.

HTH,

John

[John Z]

Thanks guys. After reading your responses, i am wondering if maybe they just need to be run for a while to loosen them. when they are run they do not squeal or make tremendous amounts of noise. But i thought they turned a bit stiff. I suspect the bus had been parked for some time prior to my buying it. Sure was a lot of fine dust/silt type of material built up in there! I think i will just give them some exercise first and see how they respond. If they need to be rebuilt, it does not take long to get to them again.  Again, thanks for the fast response. John Z

[Dallas]

John,

Here's the page from the manual reguarding the defroster motors,

IHTH

Dallas

[Kristinsgrandpa]

I would try something with graphite or moly as they don't get stiff when dry like oil or grease. 

Some teflon might also work well.

Ed

[John Z]

Dallas, thanks for the picture. I see i am missing the heater control valve knob and rod on mine. Makes me wonder about the PO approach to things. The lever to open and close the front vent is also missing?

Well, i unbolted the left hand side motor, but for the time being cannot remove the squirrel cage, so i am stopped for the time being.

It is pretty warm out today for us up here, so am going to clean up and go for a bike ride.

Thanks again to all for the help.

John Z

[Barn Owl]

They should have oil impregnated sintered bronze bearings. After forming, sintering and sizing, the bearings are vacuum impregnated with oil that provides lubricant, which is metered from the bearing to the shaft during rotation. I have seen bearings that sat for a long time and were very hard to turn. After a few minutes of use, the heat caused the oil to flow out of the bearing and they worked just fine (you cannot see the oil). You should not oil them or they will attract dirt, gum up and fail prematurely, but I would oil them if they never loosened up, knowing that before long they will need to be replaced. That being said, and no more than we use them, even after oiling them they might last your lifetime before failure.

Good luck,

Laryn

[gus]

John,

The defroster motors are probably, as already posted, permantely lubed. I've never been into those motors since they run just fine and make no noise. My defroster heat control valve, valve knob and rod  are missing also so I plan to install a plain old ball valve-other types of valves just don't seem to last in hot water situations. I think the original valve also had a thermostat so that may have been the weak link.

My lever to open and close the front vent is also missing so this must have been a common thing. My guess is that the valve and/or door linkages froze up, parts were unavailable and so there was no need for the rod and knob.

The main heater motor just aft of the front wheel on the right side is a industrial size monster that draws about 19 amps as I remember. It is supposed to have grease fittings to the bearings but I couldn't find them on mine. I think I was able to get to one side but don't remember for sure.

I just let it go because I plan to remove it and install much smaller modern bus heaters at the front anyway. It is pretty noisy so the bearings are probably dying a slow death. This motor/fan is way overkill for a conversion.

[John Z]

Gus, i like your idea of the ball valve to replace the control valve. My control valve is pretty darn corroded, and i can only hope it is wide open, as it is stuck solid. I will have to relocate it around to the left side below where the original know was since i have a ceramic heater mounted on the front panel.

As for the fan motors, i could not get the squirrel cage off, so i guess i might as well run them some. Based on the other posts, maybe the bearings will loosen up some. Right now they do not seem to tight, but they do make some noise.

Also glad to hear that i am not the only one missing the vent lever mechanism. I sort of doubt it will be worth much effort to get that all working again and work up some sort of lever.

My main heater is long gone,,, guess that is why i need to get as much heat out of the front defroster heater as i can.

John Z

[zubzub]

Hey John Z I pressume you have downloaded the 4104 maintenance manual from pd4104.com.  It has the pic dallas posted.  It's free, I had a hardcopy made as it is easier to read that way.  I think the copy shop charged $20 to print it for me (350pgs)

[gus]

John,

I think that I'll mount the ball valve on the left side of the fan box above the foot heater door so that I directly move the valve lever with no linkages of any kind. I haven't checked carefully to see if this will work but I think so.

The best things about the ball valve I plan to use are the ball is stainless steel, don't get any other kind, and the handle only turns 90 degrees from full on to full off. A brass or bronze ball will probably corrode (Turn green).

[RJ]

John Z -

This is just a WAG, so bear with. . .

Back when I was heavily into Corvairs, one of the improvements that came up in the mid-70's was the removal of the OEM heater blower motor/squirrel cage assembly over the transaxle, and replacing it with an OEM mid-70's GM HVAC blower from a Camaro, Firebird, Nova, Buick, Olds, Pontiac, etc.  (The one mounted on the firewall in the engine compartment.)  Important thing was that it had to be out of a car with factory A/C.  Seems GM used a different motor with more "umph" in the A/C-equipped cars.

When installed in the Corvair, it made a HUGE difference in the heater/defroster output - especially in the FC models (Rampsides, Loadsides, Corvans and Greenbriers for those of you in Rio Linda).

So, my WAG, is that, if the template for the squirrel cage backing plate matches the one for your 4104, this idea might work for you.  These things are cheap and plentiful at your local auto boneyard, too.  Plus, you don't have to worry about voltage issues, they're all 12VDC.  (But you might want to consider a relay in the switching circuit, to take the DC load off the switch itself.)

FWIW & HTH. . .

[John Z]

Good morning all. Perhaps everyone else already knew this and i just found out late! I was having trouble getting the fan motors out of the housing. When i opened the housing up, i thought i had to remove the squirrel cage first, unbolt the fan motor, and drop the motor out the bottom. Statements made about how difficult it was to remove them, just helped me to believe this was the procedure.

Well i got the set screw out of the squirrel cage on the left fan, but could not budge the cage. I soaked it up with penetrating oil, but still could not get it to break loose. After letting it soak overnight and still being stuck in the morning, I used a torch on it and it would not move. As i sat there staring at it, totally frustrated, i reached out, grabbed the sides of the housing, gave a yell and and a jerk all in one motion!!! WTH! The housing moved a bit towards me! I grabbed a screwdriver and lifted the lower edge of the housing an 1/8" to clear, and the housing slides out! Well i guess i should have known!

So i unhooked the wires and slid the housing out. Now i was able to drop the fan motors with the cages intact. No harm done, just spent a lot of time trying to do something that did not need to be done.

Gus - now that i have everything out of the way, i was wondering about mounting the ball valve nearer the floor on the left side. Sort of under where the original knob would have been? Thanks for the tip about the stainless ball. I have not bought the valve yet, and still need to figure out how to mount the valve to the bus.

Russ - i was going to drop off the fan motors Monday morning to have bearings and brushes put in. The left side motor turns freely but the bearing is shot. The right side motor is quiet, but turns very hard. So maybe i will swing by the junk yard on my way into town and chk out the motors you mentioned. Thanks guys.

John Z

[uncle ned]

Thanks john

been trying to remove the motors on my old 04 for years. Hope this works

ned