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DIY: Blower motor bearing lube and cabin filter replacement, 94-95 Sedan

32K views 53 replies 18 participants last post by  khomer2 
#1 · (Edited)
(Quick edit: if you're only replacing the filter, you need not go through this entire ordeal. :) This is much more involved, in order to get to the blower motor. I know a lot of people here know this, but some might not. Same thing for opening the hood all the way. I know most of the regulars here know this, but newbies might not. :) ) --Karl

Last night, I decided to have another go at removing the blower motor from my 1994 E320 sedan. While in there, I was going to replace the cabin filters. Having found there to not be a lot of info on the 94-95 cars, with their different seals at the base of the windshield and slightly different disassembly procedure, I decided to take some pictures and do a writeup. Here goes.

The first thing you'll need to do is park the windshield wiper arm at roughly 45 degrees, so that it is extended. Pull the cover off to expose the single 4mm hex bolt holding the arm onto the mechanism:


IMG_1529 by krshultz, on Flickr

Remove this bolt and set it aside. Pull the wiper arm off of its base:

IMG_1530 by krshultz, on Flickr

Now, raise the hood. Some folks might not know this - there's a trick. You can open the hood to completely vertical. At each hinge, there is a pull tab that you pull towards the center of the car. Start at the driver side. Pull on the tab and lower the hood just enough to allow the tab to move:


IMG_1531 by krshultz, on Flickr

Same thing on the passenger side:


IMG_1533 by krshultz, on Flickr

Now raise the hood completely, and behold the magnificence of your totally accessible engine bay. :) Make sure you have enough clearance up above so you don't dent your grille on the rafters of your garage!


IMG_1534 by krshultz, on Flickr

Remove both pieces of weatherstripping under the hood by the cowl. They just lift right off. Closest to the firewall:


IMG_1535 by krshultz, on Flickr

And closest to the engine:


IMG_1537 by krshultz, on Flickr

Now, remove the cover between the battery and the ECU, OVP, and other electrical components. It lifts right out:


IMG_1539 by krshultz, on Flickr

Your next target is this foam insulation between the back of the engine and the bulkhead. I hate this thing. When my wiring harness was replaced by the previous owner, the wires were routed in such a way that I can't get the wires put behind this, so your wires might be behind it. In any case, this has to come out:


IMG_1541 by krshultz, on Flickr

To do this, you'll first need to remove the plastic trim just behind it. It snaps into place. Here I'm lifting it out of one of the snaps. Look carefully at it and don't yank at it, and it should come right out:


IMG_1542 by krshultz, on Flickr


IMG_1543 by krshultz, on Flickr


IMG_1544 by krshultz, on Flickr

Now the insulation. It's supposed to be held on with four fasteners. My car only has two.:( They are plastic thumbwheels, shaped like a flower, one on each side. I could only get a picture of one. Undo all the fasteners and you can carefully lift it out without tearing it up.


IMG_1545 by krshultz, on Flickr

Now that the foam is out, you can see why we did this. There are two screws holding the center part of the plastic intake box unto the bulkhead. I'm not taking these out yet, this picture is just to show you where the screws are. This is driver side, you can just see what I think is the EGR tube at the lower left corner of the photo:


IMG_1546 by krshultz, on Flickr
 
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14
#2 · (Edited)
Now you can start removing the big rubber seal at the base of the windshield. Carefully pry up the corner, at the glass, on one side by the A-pillar. I chose to start at the driver side:


IMG_1547 by krshultz, on Flickr


IMG_1548 by krshultz, on Flickr

You can see the channels into which the rubber strip fits to keep water out of places you don't want it:


IMG_1549 by krshultz, on Flickr

And here's why we did this - you have now exposed the screws that hold the plastic drain assembly onto the car:


IMG_1550 by krshultz, on Flickr

Same thing on the other side:


IMG_1551 by krshultz, on Flickr

Take off this screen in the center of the drain assembly, just below the wiper. It lifts right out:


IMG_1552 by krshultz, on Flickr

Now we're ready to start taking stuff out. :) Start with this intake vent, on the passenger side. It is held in with one screw:


IMG_1554 by krshultz, on Flickr

Out it comes:


IMG_1555 by krshultz, on Flickr

And it's gone. :)


IMG_1556 by krshultz, on Flickr

Both sides are slightly different. On the driver side, the vent is held on with two screws, both visible here. It does not come off as its own piece - rather, it stays attached to the larger piece of drain. That'll be obvious in a sec:


IMG_1557 by krshultz, on Flickr

Now that you have both screws out by the wiper, take out four more. This will allow you to remove the entire driver side part of the drain:


IMG_1560 by krshultz, on Flickr


IMG_1561 by krshultz, on Flickr


IMG_1562 by krshultz, on Flickr


IMG_1563 by krshultz, on Flickr
 
#3 · (Edited)
Now, carefully pull the white tab that hold the drain together out, towards the front of the car.


IMG_1559 by krshultz, on Flickr

Starting with the outermost piece closest to the fender, carefully lift the drain out:


IMG_1565 by krshultz, on Flickr

Now the second piece. This one may fight you a bit, because it will still have the rubber seal by the wiper arm pressed into it. Be patient with this old plastic so you don't break anything:


IMG_1567 by krshultz, on Flickr

Same thing on the passenger side. Four screws hold this all on, two per piece. Be careful that you don't knock the clips that the screws thread into off - if they fall into the black hole of the engine compartment, they might be gone forever.


IMG_1569 by krshultz, on Flickr


IMG_1570 by krshultz, on Flickr


IMG_1575 by krshultz, on Flickr

Now remove the two screws that hold the center part of the drain/vent assembly in. These are the screws you exposed by removing the hateful foam insulation between the engine and the bulkhead:


IMG_1576 by krshultz, on Flickr


IMG_1577 by krshultz, on Flickr

Be careful and patient, and wiggle the center part out of the car, working around the rubber seal for the wiper:


IMG_1578 by krshultz, on Flickr


IMG_1579 by krshultz, on Flickr

Now, you're ready to remove the wiper mechanism. This is quite easy. It is secured with four 10mm nuts. Two like the one I've got the wrench on in this picture - NOT the bolts. The nuts. You'll see it when you look inside, the two I'm talking about attach the wiper assembly to the car:


IMG_1580 by krshultz, on Flickr

The second one:


IMG_1581 by krshultz, on Flickr

The third one, at the firewall:


IMG_1582 by krshultz, on Flickr

And the fourth one, also at the firewall:


IMG_1584 by krshultz, on Flickr

Carefully lift the entire wiper mechanism up, including the rubber seal. Don't yank on it, because there's a wire attached to the motor:


IMG_1585 by krshultz, on Flickr

Pull this wire off:


IMG_1585 by krshultz, on Flickr

Now look - filters!


IMG_1587 by krshultz, on Flickr

Fold down this clip that holds the filters in place. This is the only one that moves, do NOT try to fold down the others, or you will break them:


IMG_1589 by krshultz, on Flickr

On the passenger side, pull out the air temperature sensor:


IMG_1590 by krshultz, on Flickr

There are two filter elements that interconnect with each other. I ended up pulling out the lower one, then the upper one:


IMG_1591 by krshultz, on Flickr

Now you can see your blower motor: :)


IMG_1592 by krshultz, on Flickr
 
#4 · (Edited)
The cover for the fan is held on with several metal clips, like this one:


IMG_1595 by krshultz, on Flickr

There are two on each side of the cover, for eight total, if I'm remembering correctly:


IMG_1596 by krshultz, on Flickr


IMG_1598 by krshultz, on Flickr

The blower motor is now exposed!


IMG_1599 by krshultz, on Flickr

The motor is held down by a strap. I marked the surrounding areas with a black sharpie, so I'd know exactly how the motor goes back in:


IMG_1600 by krshultz, on Flickr

Disconnect the two wires, and take note of how they are routed under the strap:


IMG_1601 by krshultz, on Flickr

Carefully lift the motor out of its box. This is where I needed both hands, so I didn't take pictures of the motor out of the car. It looks just like it does, only not surrounded by car. :) I cleaned the bearings, on each side of the motor behind the squirrel cages, with electrical parts cleaner. Then, I used a squeeze bottle, and dribbled some Redline engine oil into the bearings. I spun the bearings a lot to make sure the oil actually got in there. I could already tell it was quieter than before.
 
#5 · (Edited)
Now you're ready to put it all back together. Put the motor back in according to the marks you made, and reconnect the wires.

Put the cover back on, paying attention to this wire, which is going to get in your way. You'll want to route this above the box, otherwise, the lid won't go on:


IMG_1605 by krshultz, on Flickr

Put your new filters in now as well. They interconnect, and only go together one way. I found it easiest to connect the two filters first, then put the whole thing onto the blower box:


IMG_1606 by krshultz, on Flickr

Reinstall the wiper mechanism, making sure to reconnect the wiring harness. I found it easiest to use a Gearwrench on the nuts that run parallel to the firewall:


IMG_1611 by krshultz, on Flickr


IMG_1613 by krshultz, on Flickr

This pillar sort of thing is part of the wiper assembly, and it just sits on top of this bracket:


IMG_1612 by krshultz, on Flickr
 
#6 · (Edited)
OK, now you have the wiper mechanism completely installed. Make sure you have replaced the air temperature sensor near the cabin filters:


IMG_1608 by krshultz, on Flickr

Now it's time to put the drain mechanism back together and finish up the job. Some of this was harder than I'd hoped to capture in pictures, because I needed both hands. But in any case, reassembly, as they say, is the reverse of removal. Here is the center section of the vent box back in place:


IMG_1614 by krshultz, on Flickr

The next piece I put on was adjacent to the center section, on the driver side of the car. Note that it slides into position using a channel, shown below. If you try to just put it in place, it won't line up, you need to use this channel:


IMG_1627 by krshultz, on Flickr

The outermost pieces (nearest the fenders) feature this funnel shape on the end. This slips into the drain tube that stays on the car:


IMG_1618 by krshultz, on Flickr

The drain tube I'm talking about:


IMG_1616 by krshultz, on Flickr

This is what it looks like on the passenger side when it's all assembled:


IMG_1632 by krshultz, on Flickr

Now that this is in position, get out those white plastic slide-on clips you took off earlier. They lock the inner and outer parts of the drain together. Here is what the clip attaches to:


IMG_1619 by krshultz, on Flickr

Putting the clip on:


IMG_1620 by krshultz, on Flickr


I won't bother to post pictures of me putting in all the screws that hold the whole thing together. Put them in, in the same places you removed them from:


IMG_1631 by krshultz, on Flickr

Once you have the drain assembly reassembled and tightened down, put the foam insulation back in behind the engine. Then, put in the plastic piece that runs alongside it. Finally, replace the two pieces of weatherstripping in the engine compartment. I did not take pictures of this part of the job, mostly because I hate that foam insulation so much that I forgot. But it goes back on the same way it was when you started. :)

For the giant rubber weatherstrip at the base of the windshield, be patient. All around the drain/vent assembly, there is a channel it fits into. Make sure you get this right:


IMG_1615 by krshultz, on Flickr

Another shot of the channels. One channel on the drain assembly, and a second one on the windshield itself. The rubber seal needs to go into all of these correctly, otherwise water could get into your blower motor, your wiper mechanism, and who knows what else, and you will be sad:


IMG_1609 by krshultz, on Flickr

All together:


IMG_1639 by krshultz, on Flickr

Finally, reinstall the wiper arm onto the wiper base and tighten down the 4mm hex bolt. It seems that the wiper arm only goes on one way - if you get it wrong, the hex bolt won't go in. You'll need to press hard, and maybe spread the hole in the wiper arm open a bit with a flat head screwdriver. It is a very tight fit.

Now, clean off your windshield, admire your handiwork, and start the car. Hopefully, your blower motor is far more quiet than it was before - I know mine is.

I hope this is helpful to someone!
 
#7 ·
Very nice and detailed writeup with pictures. Just a few comments.

1. If you go that far removing the blower off, you might want to hose off the condenser to improve the air smell, especially if the filter was never replaced. There might be rotten form from the flap to make stinky smell.

2. If you are simply replacing the filter, you don't have to remove that much, just the right side to get to the filter.

3. To save money, you can recycle the filter plastic frame and make a new filter with home furnace filter.
 
#8 ·
Thanks! Those are good catches.

1. I did attempt to clean off the condenser the first time I did this job, though I'm not sure I did as good a job as I could have. When you say "hose off," what do you mean? Hose off with what?

2. That'll be a big help for next time. Somewhere along the way, I read that you want to remove the left side if you're only changing the filter. Not so?

3. I don't think I'm quite that ambitious. :) I found the . Sometimes, I've found that if you can dig up a part number for something, like "Bosch P3632," I can find it on Amazon cheaper than anywhere else. But their "Make Sure It Fits" feature doesn't always work well. The Mann oil filters I buy there state that they do not fit an M104, but they do.

In any case, I hope the writeup proves useful to somebody at some point. I've learned so much about my W124 on this site, that I felt like I should give something back.

--Karl
 
#12 ·
I don't notice much odor at all. I chose the Red Line engine oil (not ATF) partially because it doesn't have a strong odor. Nowhere near as strong as ATF, anyway.

I'm happy to answer questions about the job, and I'm glad folks find it useful.
 
#13 ·
You live in NC too. Same here (Cary, NC) and with two E320, 1994.

The filter change for e320, 1994-1995 is covered in details by
Bentley's Mercedes-Benz E-class Owner's Bible, 1986-1995. I learned how to replace the filter from this book. Your write up is nice as it goes deeper to the blower motor, which I did it once when I replaced the wiper motor.
 
#14 ·
The Bentley's Owner's Bible sucks Yak balls....it's nothing but a glorified primer or advanced Owners Manual. Just when the reading starts to get interesting, they stop-'consult with your local dealership' kinda thing. The Mercedes-Benz Technical Companion has more, but not for 124 gassers unfortunately.

Kevin
 
#15 ·
I agree in general that Bentley's book is not complete or detailed enough. It does have a few nice sections on cabin filter change, transmission oil change, v-belt change, brake pads, etc. I found myself often using the online index in this forum to do most of the work.
 
#21 ·
I found this write-up after I found a very detailed how-to for a 1990 Coupe. Boy, am I glad I did. This is an outstanding piece that should not only be pinned in the DIY section, but should be auto-mailed to anyone with a 94-95.

I didn't have any Redline oil, so I used Mobil 1 5w30. I haven't noticed any smell at all. And, presumably from some previous repairs before I got the car, I was only missing one screw and one white clip.

Anyway, krshultz, thank you for taking the time to go step-by-step. I did the clean and lube repair last Sunday in about 2.5 hours. Except for a low-level, very intermittent chirp the next day, knock wood it's been quiet. I guess we'll find out tonight through Tuesday when the temps get down to -10 to +2.
 
#22 ·
Like I said before, whatever oils you use, the smell of it on the bearing will be amplified as the blower blows air into the cabin. Motor oil may be a tad less stinky than AFT, but not by much. I gave a good lead to check out using synthetics...you guys use and abuse whatever you want.:rolleyes:

Kevin
 
#24 ·
Excellent write up. The only thing I would add is I have found it easy to use a 7mm allen socket to remove the two retaining bolts with the six holes in them on the separating wall just behind the engine.
 
#26 · (Edited)
There are only some minor differences in procedure on the cars without the cabin filter. You don't use grease on high speed electric motor bearings...in this case, sintered bushings. The grease will attract dirt and most importantly, there is nothing to keep it on the bearing surfaces-it will fling off eventually. Normally, in electric motors bearing that use oil, there will be a felt pad saturated with oil that allows the bearing to continually wick up the oil. In a sintered bearing, the bronze sleeve is impregnated with lubricant of some sort. It's not practical for the lay person to totally clean out the bearing and re-impregnate with lubricant. So...you clean the sleeve with solvent and then re-oil until it's completely saturated. You can do this with the bearings in place. It's not the same as fresh sintered bearings, but given the fact that this blower is 'consumable', there is no easy path in getting the sleeves out and replacing with new.

krshultz's pics are great and I said so in the beginning of this thread. The only argument is the lubricant to use on the sleeves and some of you guys don't understand how electric motors work and how their bearings get lubrication. It's a lot of work to get in there your first time and you shouldn't have to go in there again....like to replace the regulator or revisit the bearings.

Kevin
 
#29 ·
Just curious.. Are there any oils/lubricants that are specifically designed for a sintered bearing system such as this that would then be reabsorbed into the sintered material after application? Sorry if this has allready been answered, trying to get a clearer mental understanding.. thanks
 
#30 ·
In the industry...they say categorically, 'no'. I say you can prolong the life of a sintered bearing by cleaning it with aggressive cleaner and then re-oiling. In a modern sintered bearing, the lube they impregnate it with is a dry lube. It's done in ovens with special machinery. A sintered bearing is usually so cheap, nobody has bothered to replicate the factory process on a small scale. And normally, I would agree with that in anything but a product where the sleeve is very difficult to get out without hurting some other part of the assembly. Plus they would argue in the industry that by the time the sleeve is starting to make noise, it's beyond its wear limits. And again, I would agree in motors where it's critical that the shafts stay aligned to prevent safety issues.

Kevin
 
#37 ·
In answer to whether this procedure works for older W124's, I just finished R&R'ing the blower on my '87 300E and the instructions worked like a champ!

My blower stopped working completely so I figured I'd try cleaning the brushes and lubing the bearings before I bought a new one. 90 minutes later, it's blowing like crazy, nice and quiet as well!

Thanks!
 
#41 ·
I can't believe members would go to all the trouble to take a look at the brushes, "clean them" and not replace them after all these yrs. Once you see the length of a new set, you won't see the efficacy in "cleaning" the old ones and putting the whole motor back in. As I've said before, Kent offers a kit to do this and full instructions.

Kevin
 
#44 ·
Also be aware that if you are getting poor blower performance but it sounds like its working fine, someone in the last 19 years may have replaced the motor but installed it backwards. Brush-holder goes on the left (Driver's side here in USA). Had mine out, cleaned the evaporator, and reinstalled in same position, no improvement. Vacuum tests were all good so reluctantly decided to replace motor. One site (FCPEURO) stated the above orientation in its description. Lightbulb went off, R&R to turn it around in a bit over an hour. Now have gale force wind in the cabin, all is well with the world.
 
#46 ·
How bad was it?



Hanno2s, I just picked up my second W124 E320 this weekend and noticed right away that the vents do not blow nearly the same amount of air as they do in my E320 wagon yet it does make plenty of noise. On a hot day like today (90 F) the A/C is not able to keep up, even though what is coming out of the vents is ice cold. In my wagon, the main vents will blow your hair back and cool the entire cabin, despite the outside temps. The previous owner just recently had the blower motor replaced by the dealer so after I read your post, some red flags went off. Any idea?
 
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