Woke Up To Acrid Odor and Noise From Basement...

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gathermewool

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Sorry for the dramatic thread title, but that is what woke me up this morning. I'm already very late for work (luckily, it's a slow day) so I'll keep this short and let the pictures do the talking.

Facts:

1. The pulley broke

2. Service company wants $500 to fix "it," not really understanding what "it" is, apparently.

3. I've pulled the motor from the sliding mount and will bring it to work with me to see what the guys think. We all work much better hands-on.

4. The blower motor spins freely and will continue to spin with only a minor tug.

5. The motor spins freely, but it will not continue to spin much after you stop imparting rotational force. There does not appear to be excessive play, and the friction is probably just old, but adequate lubrication and gunk.



If I have time I'll answer any questions, but here are my questions:

1. How do I get the pulley off? There are two set screws, one for the pulley to the threaded piece and the other to the rotor shaft.

2. Is there any way I can JB Weld this bad boy back together? Notice the wear pattern on the broken piece. The belt doesn't touch the base of the pulley.

3. Any other recommendations you guys have RE: pulling the bearing apart and cleaning/lubricating?









AS YOU CAN SEE, IT WAS A BRITTLE FRACTURE, WITH LITTLE ALMOST NO DEFORMATION - THE PIECE OF THE PULLEY THE BROKE OFF FITS BACK, LIKE A PUZZLE PIECE:




 
What did the repair company say was required?

HVAC is about the most crooked trade out there. Their prices are beyond highway robbery.
 
The pulley appears to be made of pot metal or the like, IMHO, it simply failed due to age and wear. Since you indicated there was no resistance in the motor or blower, I would simply replace the pulley (see if a steel one is available) and the belt and carry on.
 
That looks like an adjustable sheave (pulley) that allows you to tweak fan speed by adjusting the width of the sheave.

The Browning A40 belt ($10) tells you a lot about the size of your drive components.

Google your furnace model number and you might be able to come up with the exact part number and specifications (dia., pitch,shaft). Then, you can find the part to match. A one piece fixed sheavh might also work. WW Grainger is expensive for diyers, but has tons of sheaves. Appliance repair shops tend to overprice stuff too.

Also, consider an AX40 notched belt instead of the A40. Same exact size, but the notched belt travels better on small sheaves and grips better to transfer more power. Check your fan sheave also for excess wear. Make sure your sheaves line up in the same plane.

Looks like a very easy sub $50 repair.

An AX belt:
418YhZyQfWL._AA120_.jpg
 
Be sure to oil up the motor bearings too before putting it back together.

The $500 was probably a new motor with pulley and belt.
 
Originally Posted By: SVTCobra
Just as an FYI that is more correctly known as a sheave, or pronounced "shive".


Isn't that what Jewish people have when someone dies?
 
Sorry, guys, the part number is right on the pulley: VP-325-60

So, you guys are right, since VP is for variable pitch. Now I need to figure out how to dismantle it. It looks like the thread piece takes a spanner wrench type of tool, but how to unthread the outside sheave?

The sheave appears to be able to be removed entirely, being in held via interference fit...

This appears to be the same part:

[quote author=e008035 link=1425070657/1#1 date=1425125274]I have to park on the upper level to get my remote starter to work. Any other first world problems?[/quote]
 
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The furthest back allen set screw is what holds the pulley to the shaft. The other is to lock in the adjustment.
 
Loosen the set screw(s), spray down with Deep Creep, PB Blaster, or similar, tap on the old pulley, hopefully it'll slide right off (or use/rent a gear puller).
 
Originally Posted By: SVTCobra
Just as an FYI that is more correctly known as a sheave, or pronounced "shive".
I think the correct pronunciation is "shiv".

Originally Posted By: Donald
Isn't that what Jewish people have when someone dies?
Close, that's shiva, pronounced "shiv-ah" (not "sheev-ah").
 
Got a gear puller and pulled it right off...

Looks like replacements are $15-35, with the cheaper ones being zamak/zinc alloy, and the more expensive one being cast iron.

Any suggestions? The furnace is reliable otherwise, but I will be considering replacement this spring....
 
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Shiv
I'd get the 15$ one. Also check the one on the blower end for wear.
 
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Originally Posted By: SHOZ
Cast iron will last forever. How long did the pot metal one you had last?


Right, but I imagine I'll be replacing the furnace with something much more modern within the next 5 years, max.

I have no idea how long the old sheave was in service before failing, but it's pretty dirty, so at least a few years, right?

So, does anyone know if the die cast (cheaper) piece is typically good for decades or is it a [censored] shoot? In other words, is the additional $15 for the cast iron piece of a waste of money for such a short time or will it ensure trouble-free operation until I upgrade?

Thanks again for all of your help, guys!
 
I would think the pot metal one would last years too. I don't see what happened as normal wear. Either a bearing is bad in the blower of someone in the past cracked that pulley trying to remove it improperly.
 
Funny story, I got a new sheave from mcmaster carr for my chonda on my snowblower. The old one was a 1 inch, the new 3/4 crank.

I got a zinc one "for fractional horsepower" and it worked great for a couple years and exploded.

Then I got an iron one, still good.

The zinc ones are for electric motors.

I'd go iron.

Did you ever adjust the diameter? What does that get you? I ask because I wonder if you'll find an adjustable one or have to settle for something fixed.
 
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