Blower Motor Bearing/Bush lubrication

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AlexB

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Blower Motor in a Peugeot 306 had siezed so I figured I'll fit new bearings. Pulled the armature apart and found it has sprung mounted bushes and not replaceable ball bearings. Once I cleaned away all the dirt I can see a felt pad inside the housing so I figure it's unlikely to be there for lubrication as there's no oil hole in the bush to its centre. So I've lightly polished the rust from the shaft and inside the bushes with fine wet&dry emery and am now wondering what type of metal to metal lubrication, if any, to use.
Silicon spray?
Graphite?
Nothing?


BlowerMotorBearings.jpg
 
My go to for that sort of thing is my years old tin of Castrol HTB wheel bearing grease. Fairly clean and withstands higher temperatures (High Temp Bearing), and resists corrosion. Push a bit into the bush if it has indents or is porous (bronze), but clean off any excess after assembly so it doesn't get on the brushes.
My guess for the spherical bush in the felt cushion is for self-alignment and noise/vibration insulation.
Cheers.
 
Hi Alex :)
Well if the bearing appears to be porous sintered material then I would attempt to force some oil into to the pores. I usually do this by holding the bearing with a finger covering one end, fill the bearing full of oil, then press your thumb on the top trapping the oil and pressurising it a bit so it is forced into the pores till it seeps out the outside. Repeat and refill if needed. Easier to do than describe. :rolleyes:

Just as a matter of interest when I was a B&S agent they recommended using synthetic oil instead of normal engine oil in a situation where a starter clutch bearing seized up occasionally, as a warranty cure for the seizing. So they considered the synthetic oil lasted better.
Good luck Jaahn
 
I would use a light oil such as bicycle oil on the bushes. Soaking the bearings in the oil over night and let the excess drain before assembly.

When assembling the motor make sure that the armature centres itself and that the armature spins freely
 
I am with jaahn. That is how bronze bushings are supposed to be lubed.

I would also comment that it is not advised to "clean" the bushing bore at all. Just polish the rust off the shaft with scotchbrite or similar. The bronze bushing is bored to precision so any abrasives will damage the fit. Wash bushings bore with alcohol or similar if need be, clean with soft cloth but no abrasives.

After assembly check the shaft for endfloat. That is where you need to be careful otherwise the shaft will move in and out and the blower blades might touch the housing creating an awful racket. Shim as appropriate aiming for a tiny amount of endfloat.

Also make sure the bushings align properly but do not move around in the sockets freely. Some light tapping with some heavy soft object on both ends of the shaft will align the bushings. This is of course done before setting endfloat.
 
You are a sucker for punishment Alex, i would not have thought of even going this far.
 
And another thought after looking at your rotor, I would lightly sand the outer surface of that armature. Just enough to take the rust away. The clearance to the stator is tight enough that rust might get the rotor stuck or at least place undue strain on the motor. Give it a liberal WD40 spray afterwards and let it soak in and then wipe clean. That will protect it from rusting again. Check the stator for rust as well and apply same treatment if needed.
 
Matthew said:
You are a sucker for punishment Alex, i would not have thought of even going this far.
Click to expand...
Yep, definitely gone further than I had intended.
I measure the brushes as 8mm x 8mm square and as they are offset from centre line of armature I expect the face to have an arc, but haven't found anything online.
@Matthew Do you know the part number for the brushes and their length new?
 
I have some I faced down to fit, the length is more or less determined by soring compression. give the face a angular finish it helps run it in on the armature. Mine is nearly working but this was given to me and I suspect a dud regulator. The one on the car is prime to swap it into to test and try, Maybe or the brush is not making contact well enough, a large circular (rats tail) file would help there.

there are companies around who do brushes locally. Mine from ebay with copper tails these had to be soldered on carefully not to touch outer motor body on positive. How much of a hurry are you in?
 
Matthew said:
I have some I faced down to fit, the length is more or less determined by soring compression. give the face a angular finish it helps run it in on the armature. Mine is nearly working but this was given to me and I suspect a dud regulator. The one on the car is prime to swap it into to test and try, Maybe or the brush is not making contact well enough, a large circular (rats tail) file would help there.

there are companies around who do brushes locally. Mine from ebay with copper tails these had to be soldered on carefully not to touch outer motor body on positive. How much of a hurry are you in?
Click to expand...
Thanks, I was thinking of fitting new brushes if proper Bosch prefaced ones were easily available on the basis they'd last the next 20 years. I'll stick with the existing ones as there's 7mm of carbon before the braid will catch and stop travel and I can push them back 5mm to compress the spring, making them only 42% worn. The commutator copper strips will likely wear out first, they're close to half worn.
 
Just as an aside did you know that the rear windscreen wiper is ready for new brushes, remove cover, clips and fit etc. Amazed.
 
If you have a friendly local tool shop they might have on the shelf brushes you can easily modify to suit. Just make sure you get some softer ones to reduce wear on the rotor. I would suggest a comm skim is in order too.
 
Wow interesting way to make coffee, oh wait you're rebuilding it? Is this yours, what customer would be prepared fir this kind of love to their cabin fan?
 
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