Ac blower fan cage balancing

[russellrh72]

Hey guys. I bought a new ac blower motor, and in the process of taking the cages off of the old one, I broke one of the tiny little balancing tabs around the outside of the cage. It is still on there...hanging by a thread or two. No way to know if it would eventually come off one day while the cages were turning, but I have to assume it would.

My question is, how much could this throw off the balance and how much of a problem could it cause? Does anyone have any experience with this? My first thought is that there is no way I want to button up my console and find out later that I need to pull that motor assembly again. Thoughts? Should I start looking for a cage? Used...because the whole assembly new is around $250. Thanks for any advice.

Rob

[Shawn D.]

You might look at the thread on plastics adhesives and use one of the discussed options to glue it on. You can always run the fan when not installed and see how much vibration you're getting, but that won't tell you how it will sound when installed or how much life you might lose.

[russellrh72]

Yes my concern would be having it run fine now uninstalled and then having that little tab break off sometime later after being installed. Also, I wonder if those little tiny plastic tabs can cause a disturbance in the balance, then perhaps glue would as well? I guess maybe the only way to be sure would be to find a new cage

[Shawn D.]

You don't need to glue it like some infomercial doofus would -- you only need enough on the seam (and can trim excess). I think the glue would be less of a factor than a busted-off tab.

[Mike W.]

If it's about to break off, go ahead and break it off. But mark the spot with a magic marker. Install it and see how it sounds and if there's any indication of out of balance. If not, go for it. If so, pull it out and wrap a little wire around that spot to approximate the weight of the original weight. Repeat if necessary.

[a]

Chances are, it won't matter either way. The main deal is to not let the cages rub . I power up the blowers with a charger and hold them in my hand. they tend to torque your hand but they don't wobble. I've re-habbed a few blowers. No regard to balance The older our cars get, the more delicate the plastic gets. Be careful. The Borman 6, my first 528e has a re-worked AC fan with metal cages from an early '82 parts car. To make them work, they are reversed and opposite of their intended use . Perfectly smooth and quiet. My brother worked on scales for for 40 yrs. "Precision greater than the job demands is a waste"

With the fans off, set them in a beer can bushing deep in ATF or some other thin oil. Soak each end over night Set the outside width of the fans at 11 1/8 inches .

[BRRV]

With the fans off, set them in a beer can bushing deep in ATF or some other thin oil. Soak each end over night Set the outside width of the fans at 11 1/8 inches .

Somebody should make this a sticky, along with a fool-proof method of getting the fans off without destroying them. At some point, I know that Sofica heater fans are likely going to go NLA, and the cost of any of these new ones is starting to get into holy shit territory.

[a]

The Bosch motor the Behr uses has a smaller diameter than the Sofica , the shaft sizes are different so the fans won't interchange . I used cardboard from a Ritz box and electrical tape to add to the Bosch's diameter. I don't remember if I had to lengthen the wires, but that is just a pair of M/F pigtails . I only use used stuff, Is the blower motor available new? The motors have powdered bronze bushings that are porous. They are dipped in oil ,probably under pressure . The bushings take on enough oil to become "permanently" lubed. Permanently = 12- 20 yrs . BTW, the tip about adapting a Behr into a Sofica came from Shawn and the ATF in a can soak came from Ron. If the blower motor is working only on high, it isn't the resistors, its a seizing motor on its way out.