w115 blower motor options

[shadetreemechan]

I am trying to figure out what my options are for a 1975 240D with a frozen blower motor. Even if we get it freed up, the brushes are shot. Has anyone found a good replacement motor?
The motor out of a Makita cordless drill fits perfectly, but it will only stay running on low. Medium and high it draws too many amps. It just blows fuses on medium, but on high it will knock you down with the fan speed for about a minute if you straight wire it off the battery, but after that the insulation starts melting off the wires.
Anyone know enough about electrical to give advice on how to make the Makita work?

[Mike D]

Which blower motor? The heat/defrost motor or the A/C blower?

[shadetreemechan]

Does anyone know whether this would work?
https://www.amazon.com/Torque-Permanent-Magnet-DC-Motor/dp/B00NLBFOIS/ref=asc_df_B00NLBFOIS/?tag=hyprod-20&linkCode=df0&hvadid=216516247812&hvpos=&hvnetw=g&hvrand=17834690057949450035&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9052465&hvtargid=pla-353771033661&psc=1

[Sugar Bear]

I don't know what other motors will fit.

If you can free it up get oversize brushes at a hardware store or electrical motor repair and file them to fit. Be precise with the fitment particularly where the brushes contact the commutator. A poor contact at the commutator will cause arcing/burning.

Good luck!!!

[dude99]

You could also price out having a motor shop rebuild it.

[shadetreemechan]

Originally Posted by Mike D

Which blower motor? The heat/defrost motor or the A/C blower?

Its the head/defrost motor.

Filing down brushes is an interesting idea. I will look more at how they fit. They are glued into a plastic cam so it would take some pretty tedious gluing I think.
My son (its his car) did find a link for replacement brushes. It was in German but could be an option.
I am still not sure I understand why the drill motor draws so many amps. I am guessing Makita put high amperage motors in for durability, but they are always limited by the drill battery size. When you hook them up to 1000 amp battery they really sing and draw the juice.
At this point we are leaning toward ordering the motor I linked above which has a 1.2 amp no load rating, and ordering a 7 inch electric radiator cooling fan which shows 4.5 amp draw. When they both arrive we can decide whether its better to hack the mounting bracket and put the radiator fan in or try to make the new motor work in the housing.
Any other ideas appreciated. I will post what we finally end up with.
Every search I have done for 115 lists the heater/defrost motor as a problem yet to be fixed.

[shadetreemechan]

BTW. Every post you read about how hard it is to get at the 115 blower motor is correct.

[Diesel911]

Originally Posted by shadetreemechan

BTW. Every post you read about how hard it is to get at the 115 blower motor is correct.

Is there any threads on rebuilding the 115 motor as there is on the later model blower Motors?

[Diesel911]

You don't actually have to use a file the brush to work the brush to size. You can use some sand paper lying on a flat surface and move the brush across and sand it to size.

It was a long time ago in other threads they said Ace Hardware sole generic brushes.

If the brush actually needs to be glued to something the slow setting JB Weld or similar epoxy (it can take about 250 degrees F temp) might glue it on.
However, if they are carbon brushes they are easy to crack. You need to be careful when gluing not to put too much clamping force on the brushes.

[801mbz]

I have used ones untested if needed call 801 706 6871 I'll see what I have.

[Screwdriva]

The R107 blower will fit. You just need to remove the ends. It's still available new from Mercedes and will last the longest. Buying used is a spin of the roulette table, which is a bad idea given how hard replacement is.

See around the 4:00 minute mark.

https://www.youtube.com/watch?v=edXTCa4kSeQ&list=FLax2SaFHkOvRXQxqZ1YVmXA&index=3

[Sugar Bear]

Now THAT is some good info!!!

[Screwdriva]

Originally Posted by Sugar Bear

Now THAT is some good info!!!

Spread the word I suppose. OE parts only on these cars please!

[Frank Reiner]

Originally Posted by Screwdriva

The R107 blower will fit. You just need to remove the ends. It's still available new from Mercedes and will last the longest. Buying used is a spin of the roulette table, which is a bad idea given how hard replacement is. See around the 4:00 minute mark.

The comment in the Youtube piece was about the "evaporator case".
That would suggest that the 107 part is the A/C squirrel cage blower. It is quite easy to change.

The heater fan looks like a small engine cooling fan, and, as noted above, is very difficult to R&R.

[Jbyron]

Sorry but Pierre was talking about the AC fan not the heater fan. A R107 will not work as a heater fan replacement,.