The *real* blower motor on low chirp problem and reapir

Ok here goes....

I normally lurk A LOT and post some random ramblings and such but i have seen too many so called fixes for the blower motor it urks me... (no offense to anyone who has tried to solve this annoying issue for us)

We have all seen all the various threads here and on other sites saying tighten and loosen this, balance that, or the bearings are dry. First of all this is a balanced floating type dc brushed motor, with self lubricating phosphor bronze bushings. Second if the motor was out of balance it would have self destructed shortly after the chirp started.

What is going on is this is a FLOATING assembly... its floating and self aligning as it was designed and supposed to do, allowing a LONG high rpm service free life.

As you can see from the picture there is a brown PCB brush retainer around the commutator that is rubber mounted. I know a lot of you have cleaned, lubed , and or balanced and the issue seems to have gone away. What I believe to have happened is you have unknowingly reversed the orientation of the PCB when you disassembled the motor, OR you have moved the alignment within the rubber retainers.


Try this test... Remove the blower motor just like you have before, and remove the back plate exposing the motor's bottom plate and brush retainers rubber mount/isolator. Plug the motor back in, hold it in an upright orientation just like it was within the unit and turn it on low, Notice the "chirp"??? Now take and apply pressure back and forth to the outside of the rubber mounts. Notice something??? The chirp comes and goes depending upon witch direction you push.

Within the motor there is run out (play) along the length of the motor allowing the commutator to drop into the brush PCB. Depending on where your motor has settled to within its life to achieve its proper balance, you are now rubbing on that PCB.

Here is the dirty untouched side of the PCB.


Now here is the other side of the PCB where the commutator has been rubbing it.


Here is a pic showing the commutator where the PCB has been rubbing.
The shiny ring up against the winding retainers.



In a floating self aligning type motor like this there will ALWAYS be some amount of being out of balance. It is a fan that has crap "thrown" into it after all. Dirt, leaves, twigs, rocks, sand, you name it hits the impeller blades during its service causing this slight out of balance, allowing the motor shaft to SLIGHTLY wobble. This is why delphi used a self aligning/balancing motor assembly, with a rubber mounted brush assembly. (smart)

Here is where the problem is... They made the flipping hole SLIGHTLY too small in the PCB. When the run out allows the commutator to drop down it hits it...

The fix is actually very simple.
you need to remove ~ 1/32 of material tapering it outward towards the motor side all the way around from the inside of the PCB. What this does is allows the motor to float and settle to where it needs to thus "balancing" the unit.

Here's a pic, yes it is this simple!


Reassemble the motor and enjoy the silence PERMANENTLY

 

Sub'd. This drives me crazy!

 

Awesome! I just had the dealer fix mine (under warranty). If this one goes out I am trying your way!

 

This is on my to do list.

 

but what did you use to remove that material?

 

I fixed mine 1.5 years ago by adding a thin brass washer to the pack of thrust washers at the bottom, which took up a lot of excessive end play, and probably lifted the armature enough to clear the brush holder. I found the noise went away when I pushed upward on the armature shaft when it was running on Lo, so tried the shim, and have not looked back. Your discovery explains why it worked, because the end play alone should not have caused the noise.

 

subbed good thinking.

 

I took mine back to the dealership and they replaced it for free with the new model of the motor. Been working like a champ ever since, chirp free.

 

Sorry about that...

I used a dremel with the sanding drum attachment.


Yes, from what I can tell from the "updated" motor that I have seen is they basically removed shim from the top and placed it on the bottom.
This should work, well that is until the thrust washer wears a little longer and the rubber wears over time, your back into the PCB. If you look closer at my pic you will notice that the base of the commutator is flaired, this is why i suggested tapering the PCB in that direction. God forbid that they make the whole bigger

Or plan "B" if you feel adventurous is to square off the bottom edge of the commutator, but I prefer opening up the whole on the holder as opposed to with the comm.

 

Subbed

 

Worked great! Thanks!

 

Phil For President!

 

I think im gonna do this during the weekend!,

 

Coolio, I have removed and cleaned it every 2 years or so, whenever I hafta strike it to engage the fan. Next time it's in my hand I'll try this.

 

Thanks for the nice write up & pictures. I'll try this before going to dealership for warranty replacement.

 

I pulled the fan out of my 2010. The brush holder is not made from fiberglass / epoxy like shown. The brush holder in my motor was molded plastic.

The clearance on the center hole was more than adequate. There was no wear or rub marks on either the brush holder or anywhere on the armature.

Previously, I had done as originally mentioned, pulled it apart (only the brush end), cleaned and lubricated the bushing. It worked for a little while.

This last time,I did make a change though. Not finding any contact, I cleaned the end of the shaft and other parts, I reassembled the motor and found that with the screws barely snug, there was no end play in the motor shaft. Ultimately, I removed the oem rubber washer that is installed to control end play on the shaft. I replaced it with a metal washer slightly thinner. Once assembled, I ensured the motor shaft had axial end play.

Removed the end cap, lubricated the bushing and again reassembled. Again verified the shaft had clearance.

Works so far.

Not saying this will be the repair, I wonder if the rubber washer was expanding with heat, and applying pressure onto the bushing.

Time will tell.

PK

 

I planned on doing the "old" fix today... between those threads and now this one, I am looking forward to getting this problem fixed. It has always driven me crazy!

 

^^
This.

Frank

 

The write up seems great but the pictures have gone away. Possible to repost?

Thx!

 

Sorry Webshots died and took my pics with them... I will have to see if i still have the pics and repost when i get them hosted again.

Found something new on mine as the chirp VERY slowly came back...
One of the washers wore down to nothing allowing the com to drop into the brush holder.
Luckily i had a bunch of phosphor bronze bushings laying around to "shim" it back up.
All better again