Microfilter Replacement in a 92 - 7351 (E32)
December 4, 1996

By: Dave D'Arche

(If you'd like this emailed to you via within minutes, send a blank email to microfilter@mesaperformance.com)

Well, without a shop manual and with some help others, I was able to get it done. Parts range from $30 or so and you save about $75 in labor and having to drop the car off, pick up, etc. All total, maybe less than 2 hours on your first attempt. You can cut about 30% on subsequent installations.

Remove the entire glovebox, (easier said than done) (Next time I do this, I will experiment with leaving the glove box in and pulling it out to the farthest inward position and then tying it up and out of the way. If you can get in under it and still work, this can save you an additional 45 minutes or so.) This was my first time so it was more difficult. Maybe these instructions will cut the time in half.

Locate the two "shock absorbers that dampen the door opening. Left side of the glovebox. One front and one rear. Remove the clips that hold the BOTTOM of the shocks in both front and rear. Remove the right nylon hanger from the BOTOM by removing the clip.

I also removed the top cover of the compartment, the piece that holds the lamp assembly. (Not certain now, if this is necessary to the process.) One screw in the front, middle will allow the entire piece to be removed. The rear of this piece has a slide on connector that attaches to the back of the glove box itself. It keeps things in the glove box from bouncing out onto the floor plus has some noise dampening insulation attached. Slide this off the back of the glove box. Top should then come out. Note that it has 2 plastic loops that slide over another large black steel tubing at the top of the under-dash. Unplug the two connectors that go to the light. While you are, locate the flashlight connector and note where the wire is fed, down the left side of the glove box. Remove the 3 metal clips that hold this wire into a channel that runs down the left side of the glove box. Remove the flashlight connector by compressing the holding points from the socket area.

Now, locate the main pivot point of the glovebox. (Not the large black steel tubing in the back.) Note that it is a _" or so black rod attached to the back of the glove box and it affixes at two points, left and right. This rod has a clip on both sides and they need to be removed as well. (This is the part I am not certain of if I did it right. I got it out, but check it out closer yourself.) I chose to not mess with the pair of large, brass nuts on both sides of the box, where the _" rod is suspended and where the pivot point is. I chose to "slightly pry" the rod out of the right side and once out, you can the glove box down and remove it from the left side. Locate the large black steel tubing, find the pivot points and remove any clips from the left and right side. If I am recalling correctly, at this point, it will come out completely.

Remove the carpeted panel on the left side of the passenger footwell. (One screw, mid panel).

Underneath this carpeted panel, is a black, plastic cover. This cover resembles the carpeted panel but is smaller and more rounded. It is directly under the carpeted panel., on the left side of the passenger footwell. It may have a sticker on it describing that the car has a microfilter and also has an airbag both in German and English. Mine did.

This plastic panel is removed by one screw in the front, near the top right edge of the console and a pull-out plastic pin in the rear of the plastic panel.

Remove the wrap-around duct that goes from the left side of the console, in the passenger left-side compartment and wraps around the front of the passenger leg area. Two screws at the firewall area, where the passenger knees would be. Remainder of the duct removes near the console with an apparent press-fit hardware. Can be gently pulled off.

Remove the wires from the HVAC control unit (if that is what it is) It has a yellow and a blue connector and a bundle of wires on each connector. Both connectors are very cool, German connectors. Lift the white lever and the connectors pop right off. Right next to these 2 connectors, is a black connector on another part. This can be removed by pinching the connector in the orientation toward the front and rear of the car, on a spring type release and pulling straight up. I would recommend that you tie these connectors up with twine or something and tie them out of your way for the duration of the project. Tie them in the direction of toward passenger compartment , up as high as possible.

The HVAC control unit (with the blue and yellow connector bundles can be pulled toward you on the passenger side, but not until you pinch a plastic clasp near the middle of the body of the control, which loosely holds the unit in place. Once unclasped, you can manipulate the control unit toward the passenger leg area, by about 6"-8" which will generally be enough to get at the filter area. (It will need some further manipulation out of the way as you remove and replace the microfilter cover.)

The reason the control unit does not come out completely is that there is another connector and bundle of wires on the driver side leg area. Unless you want to find this and unplug it, (this means removing a bunch of the driver side kick panels and probably the console to get at this connector. It appears easier to do the above and not take all the console stuff out.

In describing the general area of what you are seeing, the HVAC control unit with the blue and yellow connectors is the most forward item, closest to the firewall. The next "item" you see, going back toward the console is a white plastic cover with a large black connector mounted into the center of the cover. This is the black connector that I described above, in which you have already removed the wiring connector. This remaining piece of the connector is mounted on the face of the white plastic cover. This is the infamous "sword" (temp control unit?) with the 3-4 resistors that epoxies onto a circuit board. Remove two screws here and the sword will pull out. It is quite long, possibly 24". It can only go back in one way, as the opening is specific.

What you now see on the white plastic cover is the hole where the sword went it. If you can peer into the opening of the cover, you will see the microfilter is on the left side of this opening. You may see the horizontal lines of the filter. This cover needs to be removed. It has one screw on the lower portion of the cover and a strange black lever on the top of the cover. Remove the lower screw and spin the lever up, away from the latch it fits into. The white cover will come off and expose the filter. Reach into the opening and grasp a small flange that is facing you and the filter can be coerced out of its spot and pulled out in a direction similar to how you removed the "sword". Notice the position of the filter as you remove it. It has a "TOP" and an arrow facing to the left stamped into the top of the filter channel. This is how the new filer must be oriented.

Replace the filter and note that it will not fit into a specific spot or snap into a location with authority. Do your best to get it to locate on the left wall of the opening. When you replace the white plastic cover, it has a specially designed flange on the inside that holds the microfilter in place. Mess with the cover until it is in place (needs some patience) so that you can move the top lever into its locked position and then put in the lower screw. Check that the cover is fitting snug against the opening.

Replace all the connectors and push the HVAC control unit back into its resting area. Mess with it until you can get it to snap back into the holder.

At this point, hopefully you can remember the rest of the order of parts and pieces. I found the glove box to be the biggest challenge. Good luck! Once completed, the blower and the vents come alive with unrestricted air flow. How nice!

Dave D'Arche

ddarche@hooked.net