[bigbui]

Need some help here. I recently replaced my home blower motor but I'm having problems with the metal fan housing falling down back on the motor. After the install the motor and tighten the 1/4 nut on the motor shaft, it works fine for about 15mins and then it slides back down. And tricks? I've taken out 3 times and tighten that nut on the shaft but it keeps sliding down. And yes, I did line it up on the flat side of the shaft. Any help would be fine.

 

[Yoyizit]

You could drill a 1/16" hole through the fan fitting and motor shaft and put a paper clip (0.036" in dia.) or brad (?" in dia.) through the hole to act as a cotter pin. You have to bend it over at one or both ends. Hardware stores have numbered drills that go smaller than 1/16"
Or you could wrap teflon tape around the set screw so it keeps its position.
Or you could epoxy the shaft to the fan fitting (not recommended).

 

[yuri]

Is it vibrating excessively. I assume you are talking about the squirrel cage blower wheel. You may need a new set screw/bolt. If it vibrates excessively then a new wheel may be required. On some of the 1/2 hp motors you need to tighten it with an 8" crescent wrench REAL tight. Wear gloves or you may dice up your knuckles real bad if it slips.

 

[bigbui]

Than you for the info. I was thinking about drill a small dip on the shaft. It is not vibrating excessively. Only when the cage drops down and rubbers against the housing. I'll try some teflon type on the set screw also. The motor is a 3/4 hp. The factory on was 1/2. I bought a universal motor for $90. OEM wanted $210. The cotter pin idea sounds good. Think I'll drip a dimple on the shaft unless you advise against that.

 

[Yoyizit]

drill a small dip on the shaft.

I doubt that will hold.

It could also be a stripped set screw. I got to sell a lot of those when I worked at the local h/w store.

Or you need to retap the hole and/or use a helicoil, but
I don't see any downside to the pin method,
your labor may take as long as the round trip to store
and the clips are free.

Good luck!

 

[bigbui]

It could also be a stripped set screw. I got to sell a lot of those when I worked at the local h/w store.

Or you need to retap the hole and/or use a helicoil, but I don't see any downside to the pin method.

Good luck!

It's possible but the hole/thread feels fine. It was able to hand tighten it down to the shaft and then used a wrench to tighten it. And out of the 3 times of removed it, it was on hard, but once I broken it loose, I could untwist it with my hand.

 

[Yoyizit]

It's possible but the hole/thread feels fine. It was able to hand tighten it down to the shaft and then used a wrench to tighten it. And out of the 3 times of removed it, it was on hard, but once I broken it loose, I could untwist it with my hand.

If it holds for substantially more than 15 mins. you might be home free.:thumbsup:

 

[Chemist1961]

You might also check the drive shaft and clean and dress the area where the set screw seats. Make sure there isn`t a burr holding the screw from fully hitting the shaft. My shaft actually had an indentation from the setscrew being torqued down over the years. If you still have to crack that screw free of the threads it sounds like it`s just not travelling far enough through to hit the shaft.
If that`s all good check the vibartion like Yuri says . Did the squirrel cage get bumped and bend a fin...

 

[biggles]

might want to try a hardened steel allen screw instead of a wrench square head