Blower motor interchange? - PeachParts Mercedes-Benz Forum

Zerohour3k · #1 02-10-2010, 09:41 PM

Here's a question for all you folks who know a bit about motors (or just plain like to tinker).

The blower motor on my 83 300D (w123) is on its way out. I have a "spare" motor laying around from an 84 300D, which sadly is also fairly worn out. Needs new brushes, but the commutator is fairly ridged and worn, so it's probably not worth replacing the brushes on it.

My question is this: Is it possible for me to use a 300SD blower motor in place of the W123 one? I'm talking the actual motor here, not the whole squirrel cage assembly, which I managed to take off. Bosch blower motors for the w123 part number are incredibly hard to come by these days, and are kinda pricey. I looked up siemens 300SD motors, and they're VERY close to the 300D motor in appearance.

So, can I pull the trigger on this, or is there some major difference that'll have me pulling my hair out, or setting my car on fire?
Thanks!

rhodes2010 · #2 02-10-2010, 10:29 PM

This is a really good question.

I recently replaced both my W123 and my W126 blower motors and did
not take the time to compare. But they are darn similar.

H-townbenzoboy · #3 02-11-2010, 01:22 AM

Quote:

Originally Posted by Zerohour3k

Here's a question for all you folks who know a bit about motors (or just plain like to tinker).

The blower motor on my 83 300D (w123) is on its way out. I have a "spare" motor laying around from an 84 300D, which sadly is also fairly worn out. Needs new brushes, but the commutator is fairly ridged and worn, so it's probably not worth replacing the brushes on it.

My question is this: Is it possible for me to use a 300SD blower motor in place of the W123 one? I'm talking the actual motor here, not the whole squirrel cage assembly, which I managed to take off. Bosch blower motors for the w123 part number are incredibly hard to come by these days, and are kinda pricey. I looked up siemens 300SD motors, and they're VERY close to the 300D motor in appearance.

So, can I pull the trigger on this, or is there some major difference that'll have me pulling my hair out, or setting my car on fire?
Thanks!

I looked into it and I was told that despite their similar appearances, the W126 motor is slightly too tall to work with the W123 assembly.

MBZ123 · #4 02-11-2010, 03:13 AM

Quote:

Originally Posted by H-townbenzoboy

I looked into it and I was told that despite their similar appearances, the W126 motor is slightly too tall to work with the W123 assembly.

Are you sure? I'd check the specs on the motors. Shaft length, motor housing diameter, etc.

Zerohour3k - How did you get the squirrel cage off w/o absolutely ruining it? Also, check your local parts store. Was at Autozone, (out here in CA, but I'm sure all the others are the same,) saw the picture of a blower ass. on the marketing crap pasted on the wall and thought what the hell. Asked the clerk and seconds later he and I were in the pallet racking going through boxes...didn't get one but saw alot that might work.

rhodes2010 - What did it cost to replace and were they new/used from where?

FNHB

Zerohour3k · #5 02-11-2010, 10:08 AM

Quote:

Originally Posted by MBZ123

Zerohour3k - How did you get the squirrel cage off w/o absolutely ruining it?

FNHB

First, PB Blaster, and lots of it. Squirt down the shaft and let it sit for a day or two. PB Blaster is seriously just concentrated magic in a spray can.

I used two jack stands to support the cage on both sides, and used a (I think it's called) punch and hammer. Basically a large chisel-looking thing with a rounded edge on the tip. Found it in a toolbox that I inherited.

Took a hammer to the punch, gave it a couple of really good blows, and the blower dropped right out. Just make sure the cage is very well supported, otherwise you'll end up shattering it to pieces. A lot of this procedure is luck, unfortunately. Sometimes no matter how careful you are, the old plastic is just too brittle and will shatter. I don't recommend trying this unless you have a spare blower laying around.

As for the motors, I look forward to hearing back from anybody who might have a W126 and W123 motor laying around, and can provide some insight as to their dimensions.

andrewjtx · #6 02-11-2010, 12:02 PM

I went through a real PITA time of getting a new motor for my 84 TD.

I don't know when the split happened of the top of my head, but the older motor has a more enclosed casing on it. You can't work on the brushes for this model. The newer (83-85?) has the accessible brushes. The older model has a larger circumference and does not fit the black plastic base.

The 126 blower motor is about 1/4" longer than the late model 123... Don't ask me how I know. But I have a brand new 126 motor for sale if anyone needs one. They look identical to the late model 123, but no dice on fitment.

andrewjtx · #7 02-11-2010, 12:08 PM

Quote:

Originally Posted by Zerohour3k

I used two jack stands to support the cage on both sides, and used a (I think it's called) punch and hammer. Basically a large chisel-looking thing with a rounded edge on the tip. Found it in a toolbox that I inherited.

Took a hammer to the punch, gave it a couple of really good blows, and the blower dropped right out. Just make sure the cage is very well supported, otherwise you'll end up shattering it to pieces. A lot of this procedure is luck, unfortunately. Sometimes no matter how careful you are, the old plastic is just too brittle and will shatter. I don't recommend trying this unless you have a spare blower laying around.

Same here on the cage removal method. I supported my cage with two paint cans, placed a piece of foam under the motor to catch with without hurting anything.

In the end, I wound up just buying a brand-new Behr unit with a new cage and mounting plate. I wanted to make damn sure I had good A/C this last summer.

kerry · #8 02-11-2010, 12:20 PM

I have a thread on here with directions for replacing brushes on the W116 blower motor which also has a closed motor with no easy access to the brushes. However, they still can be replaced. I suspect the same process is possible on the enclosed 123 motors.

Zerohour3k · #9 02-11-2010, 01:10 PM

The W123 motors are fairly easy to access the brushes, but both motors I have are fairly worn, and have grooved commutators and worn bearings.

I was hoping for a drop-in replacement that I could use, rather than hunting down a $150-200 Bosch DC motor, or worse yet... a $400+ blower unit.

andrewjtx · #10 02-11-2010, 01:21 PM

They stopped selling the motor only. I'm not sure if Behr has a limited supply that they have already mounted in the base with new cages.

My guess is, that Behr probably has an exclusive partnership with Bosch. Behr may be the only entity that has the buying power or desire to order the qty needed for Bosch to fire up the line for that specific model of motor.

Either way, if you want a new late-model 123 motor, you have to buy the complete Behr unit.

On the bright side, my sounds and works beautifully. For the price, it had better.

jbach36 · #11 02-11-2010, 02:51 PM

You don't have to reassemble everything, but put the fan in the compartment (at least mine has one), and turn it on, see what happens. If it works, it should be fine. I doubt it's a different electrical load.

jeff 1991 300d

MBZ123 · #12 02-11-2010, 05:10 PM

Quote:

Originally Posted by Zerohour3k

First, PB Blaster, and lots of it. Squirt down the shaft and let it sit for a day or two. PB Blaster is seriously just concentrated magic in a spray can.

I used two jack stands to support the cage on both sides, and used a (I think it's called) punch and hammer. Basically a large chisel-looking thing with a rounded edge on the tip. Found it in a toolbox that I inherited.

Took a hammer to the punch, gave it a couple of really good blows, and the blower dropped right out. Just make sure the cage is very well supported, otherwise you'll end up shattering it to pieces. A lot of this procedure is luck, unfortunately. Sometimes no matter how careful you are, the old plastic is just too brittle and will shatter. I don't recommend trying this unless you have a spare blower laying around.

As for the motors, I look forward to hearing back from anybody who might have a W126 and W123 motor laying around, and can provide some insight as to their dimensions.

Do you happen to have the part number off the old motor? The current motor offering that most closely resembles the old is in there and has a downloadable pdf. Try it. If I find it in my excuse for an e-filing system, I'll post or forward it on. Can't remember how big the file was.

FNHB

Zerohour3k · #13 02-11-2010, 05:17 PM

The old part number for the W123 bosch motor, is 0130111103. Mine still spins, but will blow a fuse from the draw it requires (gummy bearings and worn commutator + brushes).

There HAS to be a reasonable drop-in replacement, I'd think. I mean, it's just a DC motor.

andrewjtx · #14 02-11-2010, 05:39 PM

Quote:

Originally Posted by Zerohour3k

There HAS to be a reasonable drop-in replacement, I'd think. I mean, it's just a DC motor.

Heh. I snorted on that one...

Let me see what part #s I have at home. I collected several motors that didn't work for me (size-wise) but plugged up and ran very well.

MBZ123 · #15 02-11-2010, 05:46 PM

Quote:

Originally Posted by Zerohour3k

The old part number for the W123 bosch motor, is 0130111103. Mine still spins, but will blow a fuse from the draw it requires (gummy bearings and worn commutator + brushes).

There HAS to be a reasonable drop-in replacement, I'd think. I mean, it's just a DC motor.

Yeah, thats the same number I had on mine. The new offering from them is leterally something like one digit's difference, iirc. Was directing you toward the pdf to get dims from it, they're pretty informative. I'm sure somewhere there's a cheap replacement if you don't want the $70 auto parts store variety. Just haven't gotten that far myself.

FNHB