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1973 model roof a/c fan problem
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posted
Hi folks! I just bought a great 73 Barth and i'm so excited. 454 on factory propane.

I switched on the roof a/c and it hummed something awful, the fan squealed a bit, then it kicked in. It blows cold fine and the 3 fan speeds/a/c speeds work. However, now it squeals constantly and the fan blades are 'slipping.' Is it the bearings in the fan motor/clutch? I went up top with it on low speed, removed the cover, and watched it catch briefly, then squeal and stop. Do i need a new fan motor?

Thanks!


73 Barth 23 ft
Chevy 454 factory propane
116k miles, rear double bed
 
Posts: 23 | Location: Vancouver, BC Canada | Member Since: 07-09-2007Reply With QuoteReport This Post
First Month Member
Supporting Member of Barthmobile.com 11/13
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Propane, eh? Canadian?

May I suggest you add a few details to your signature so we can help you better?

Anyway, welcome. I would get up on the roof and spray the motor bushings with PB Blaster and work it by hand and see if it frees up. If it shows a marked improvement, have someone run it and then stop it so you can shoot some more PB in there to dissolve some of the corrosion. Once it is free, shoot it with brake cleaner and then Dri Slide, stopping and starting the rotation. While you are up there, make sure all the electrical connections are clean and tight and replace the capacitors. Look for cracks starting on the shroud and repair them to prevent losing it later.


.

84 30T PeeThirty-Something, 502 powered
 
Posts: 6169 | Location: AZ Central Highlands | Member Since: 01-09-2001Reply With QuoteReport This Post
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Hi Bill,

I did spray the bushings with a similar penetrating spray-we're talking about the bushings where the fan spindle inserts? It spins by hand already. It feels like it is actually slipping and free spinning in the bushing somehow. I will try it some more and use some brake cleaner and dry slide as suggested. Just wondering if the bushing is actually worn, or if it seizing? Am I replacing the capacitors in the the rectangular motor control box to the left (facing forward)?


73 Barth 23 ft
Chevy 454 factory propane
116k miles, rear double bed
 
Posts: 23 | Location: Vancouver, BC Canada | Member Since: 07-09-2007Reply With QuoteReport This Post
First Month Member
Supporting Member of Barthmobile.com 11/13
posted Hide Post
quote:
Originally posted by MGmobile:
Hi Bill,

I did spray the bushings with a similar penetrating spray-we're talking about the bushings where the fan spindle inserts? It spins by hand already.


I am talking about the shaft that sticks out of each end of the motor. The last few I worked on had a fan on each end, secured by an internal hex setscrew.

quote:
It feels like it is actually slipping and free spinning in the bushing somehow.


I am having a hard time visualizing what you are saying. Do both fans rotate with the shaft?

quote:
I will try it some more and use some brake cleaner and dry slide as suggested.


Sounds like, aside from the squeak, there might not be any improvement with better lubrication.

quote:
Am I replacing the capacitors in the the rectangular motor control box to the left (facing forward)?


My mention of replacing the caps is just a general maintenance issue. Caps age and make motors work harder and hotter. Replacing them after 30 years is always a good idea, but they are probably not the root of your problem.


.

84 30T PeeThirty-Something, 502 powered
 
Posts: 6169 | Location: AZ Central Highlands | Member Since: 01-09-2001Reply With QuoteReport This Post
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Bill,

Thanks for the patient explanation. I think we've found our problem. Of course there is a front fan on the other side of the fan motor, which i forgot to check/lubricate. This is why the fan squeal is right above the control panel below..duh. I'll bet this front end of the fan/shaft is hanging up. I'll get on the front one tomorrow and hopefully it frees up everything!


73 Barth 23 ft
Chevy 454 factory propane
116k miles, rear double bed
 
Posts: 23 | Location: Vancouver, BC Canada | Member Since: 07-09-2007Reply With QuoteReport This Post
posted Hide Post
Ok, i've taken off the fan cover. However, the front side is completely sealed by monofoam. I tried spraying some lubricant straight down on the shaft. Then i turned on the fan and rapped the motor with a rubber mallet--and it came on! However, after running it through the speeds for a bit, it seized up. Now it won't even spin by hand. I've included photos. I imagine the foam insulation has to be removed to get access to the front fan shaft?



73 Barth 23 ft
Chevy 454 factory propane
116k miles, rear double bed
 
Posts: 23 | Location: Vancouver, BC Canada | Member Since: 07-09-2007Reply With QuoteReport This Post
posted Hide Post
Fixed! Unfortunately i started chipping at the insulation on the motor, until i realized the cover for the front cooling rad just pulls off...doh! So i pulled off the drum fan and lubed the front shaft and it works perfect now. Now i'll have to carefully reapply some spray insulation on the motor side of the front fan, avoiding the shaft. Thanks!


73 Barth 23 ft
Chevy 454 factory propane
116k miles, rear double bed
 
Posts: 23 | Location: Vancouver, BC Canada | Member Since: 07-09-2007Reply With QuoteReport This Post
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    Forums    Tech Talk    1973 model roof a/c fan problem

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