greetings, all! having the age-old problem with the seemingly
infamous 300D blower motor. made the mistake of buying "used"
replacement (i think it's older than the one i burned up). now looking at trying to replace the motor assembly. i saw a lengthy thread on how the brushes on these are victims of gravity and the only real solutions seem to be new unit or new
motor, if available. my problem is i'm mechanically uninclined enough to need help getting the fan blade off. i've tried pulling,
driving, unscrewing -- well, you get the picture.

any guidance on removal of the fan blade assembly from the
motor shaft would be appreciated. also any input on whether
anybody's been able to replace the motor without buying the
whole kit and kaboodle (the aforementioned thread seemed to
end last spring with no follow-up on the results).

mercy me!

ps -- it's a bosch motor.

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rayroyw
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'85 380SE (238,300) my "new" old car!
'84 300D (303,000+)
'72 250/8 (mercy heaven)

Hold the fan, tap the shaft, catch the motor.
No big deal to replace brushes.
Look for an auto eletrical repair place.

The electric fan motor on my 123 had a small allen screw holding the fan on the shaft. You will need to loosen that before beating the stuffings out of the assembly.

A regular 2lb coffee can works great for the job. I just crimped around the top to make a platform and placed the motor in. I used a pin punch and hammer and drove the shaft out. This was on a 83 300D with a Siemans fan motor which I thought had bad brushes. I was wrong. The brushes were fine after all.

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Orland Park, IL
1985 300SD 215,000 miles

I can't recall for sure if I had an allen screw to remove first. I used a small drill bite and drilled into the center of the motor shaft. Stepped up the drill bite size and continued to increase the hole size. Before I got close to the plastic, I created enough heat and the drilled metal motor shaft slipped out of the plastic fan with no fan damage.
Replaced motor for about $85.
87' 300SDL 293,000
blower fan repair around 260,000

thanks for the insight.

right now, the motor seems to be running ok (temporarily, i'm sure). i guess i accidentally found the brushes, which don't look
like brushes at all (am i right on that?) but are two small spring
loaded blocks of graphite/secret metal combination at the bottom
of the motor housing. i took those out and of course the surfaces
had significant ridges in them. i sanded those surfaces smooth
again and reinstalled; been running true for two days in a row
(a record i assure you!). since it's so soft, i imagine the ridges
will reappear in short order.

if those are the brushes, how large are they when new? these
are about 1/4" cubes. just wondering how much is left.

of course if they're not the brushes, then i guess i've created
a bigger problem that has yet to rear it's ugly head! (some people shouldn't be allowed to pick up a screw driver, right?)

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rayroyw
_______
'85 380SE (238,300) my "new" old car!
'84 300D (303,000+)
'72 250/8 (mercy heaven)

The "brushes" are very soft metal compound. Those ridges are caused by the same on the armeture. I just used a drill motor to spin the armeture, with one end stuck in the backing plate, and a flat file to 'lathe' the armeture even again. Seemed to work just fine.
By the way, if the brushes were quite shortened, you can count on them failing again soon. Easy to replace, just get some that are close and file then down to fit. File the ends to match the angles of the old ones, and file the sides to slide easily in there. Solder on the wires and you are warm again.

Sounds like some good advice from Old Deis. I did the ,replacing the brushs thing. the auto elec shop had brushs that fit and they only cost a buck for both. He recommended using the old "Sleeves " for the wires. Also it would have been handy to have one of those things that hold your work and usually have a magnifying glass. Anyway I had a problem holding parts together while soldering. Good luck, its a fun little project and you save some $ .

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1985 Euro 240D 5 spd 140K
1979 240D 5 spd, 40K on engine rebuild
1994 Dodge/Cummins, 5 spd, 121K
1964 Allice Chalmers D15 tractor
2014 Kubota L3800 tractor
1964 VW bug

"Lifes too short to drive a boring car"

Old Dies, used your lathing technique and it worked like a charm
on the armature. found some "close" brushes, cleaned up all
the contacts, and right now i have heat like south florida in august.

thanks, guys.

__________________
rayroyw
_______
'85 380SE (238,300) my "new" old car!
'84 300D (303,000+)
'72 250/8 (mercy heaven)