Found a good blower motor substitute by harvesting the blower motor from a 1995 Volvo 850. P/N 6820812. This blower motor is available on the Jungle Website for 36$ free shipping. The whole process took me about 3 hours with interruptions. 2 modification are necessary when using this Volvo blower in an a 928. Despite the low price, I don't foresee a false economy because the Volvo blower motor seems high quality, appears identical and works as intended. Also, a few hard to find small parts from the Volvo blower car be repurposed, these offer some value for balancing. I had magic blower motor syndrome and no amount of tweaking of the resistor pack helped. When my original blower motor was inspected there was drag on the blower shaft and the commutator was badly scored.
Two mods are needed to use the Volvo blower motor.
1. Shortening of the shaft to 24mm
2. Replacing the male spade connector with a female
Here are some Picts. This project is for an experienced 928 DIYér and requires a few hours of effort
First thing to do is harvest Blower motor from the new Volvo Unit.
New motor shaft has to be shortened from 36mm to 24mm using a cut off wheel
Volvo blower motor appears identical, dimensions, weight winding size, and magnet size and over all general design appears the same.
928 blower fan wheel fit on Volvo fan motor with a few gentile taps. The lack of splines doesn't seem to matter.
Tiny weights from the Volvo fan were re-purposed to more finely balance the 928 fan. Porsche techs got the location of the weight right but a bit more was needed to eliminate all the grumble. You can see an intermingling of old and new weights.
Female spade connector needs to be added the brown wire.
Final Assembly
Testing and balance check. Verify polarity of wiring is correct before re-installing the blower assembly back in the 928
Old blower motor and new Blower motor with shortened shaft. Shaft was shortened using a cut of wheel and finished out by running the motor against a flap disk.
by icsamerica
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some fan motors draw more current. It makes sense to check this prior to taking things apart.
Theo
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