[r3vmatch]

Note: I will update this posting with the few pictures I took when I have a chance to grab them.

I know I'm bumping a "super old" thread, but I thought this would be helpful for anyone else who attempts the "gears repair". My "key add" is to hot glue the replacement black+white gears on your bench before installing them and then removing the hot glue after the fact. I also suggest running a flapper motor calibration routine in ISTA/D (Rheingold) after everything is done (it might be accessible in INPA as well) to make sure all is well.

My 3.0si also was making a popping / clicking noise each time I got into the car (very frustrating) and this thread helped me realize what was wrong! I have the IKHA ("automatic") AC system if it matters, Left-Hand-Drive. While a lot of the postings here helped me gain confidence getting "access", doing the actual gear repair took me quite a bit of trial and error. In my case my black gear was missing a tooth which caused the popping noise.

Budget 6-8 hrs for this and have your car some place where you can resume the work the next day if you can't get it done in one go. It took me two days to finish it. Changing the filter IMO was pretty fast and easy (once you know the filter is wider rather than taller when installed), but doing the gears was pretty painful.

I was upside down underneath the passenger footwell MANY times, with my feet dangling up in the air to do this. Often my flash light ended up accidentally shining in my face as I attempted to get the gears back in place and my back was pretty sore due to all the trial and error. Hopefully my detailed write-up will save you some of this pain and frustration.

Tools you need if you repair it my suggested way:


- Very sharp Xacto knife, a hot glue gun (yes, keep reading), a small mirror on an adjustable metal arm, adjustable brightness LED flashlight and the entire "small AC parts" kit from BMW (~$40 for me), pair of small curved tweezers, plastic "pick" tool and some isopropyl alcohol.

- Parts kit: There are two different "AC small parts" kit, one for "IKHA" which is the automatic AC system and the other parts kit "IKHR" is for the "non-automatic AC system". This isn't super obvious unless you go read about the BMW AC system in one of their training PDFs what this designation means in the BMW TIS PDF.

- 10mm socket for negative terminal car battery, 8mm socket for white GM box (2 screws), long-ish philips screw driver for bottom panel acces screws (2)

Getting access:


- I removed the two philips screws and removed the bottom cover under the glove compartment and detached the connector the goes to the footwell light. The panel droops down, and you pull it towards the seat to unseat it.

- I unplugged the negative terminal on the car battery and then completely removed the white GM box (two screws, three cables for attachment) to make changing the gears easier since my head was going to be in this space often.

Note: On the GM, two of the three connectors came off easily, there is a center point to depress, and then the white clip flips over and the connector releases. The third (thicker) connector slides completely in one direction which mechanically releases it from the GM box and then you can detach. Mine took some effort to slide it all the way to release it.

- With the plastic and GM out of the way you can work more easily in this area

- The air filter housing cover has a clip on the right side (L-shaped, wider than taller) depress the clip and then slide to the right, comes off easily

- When I pulled the filter, numerous leaves fell down, not quite as bad as what I saw in other posts but more than expected

Gears replacement procedure:


1) Disconnect electrical connection to flap motor

The motor is pretty visible once you've pulled the panel, it's to the right side of the car. There is a 4-pin connector with an indentation / locking mechanism. Press with a plastic pick tool on the electrical connector to release it and then pull the connector/wires from the motor.

2) Remove flap motor

On the side of the motor near the electrical connector, there is a plastic clip on the motor housing that you press down and gently tilt the motor and pull it out of the way.

Note: The motor doesn't have any "stops" and during replacement I had to adjust the position of the motor numerous times to get it re-seated with the gears, but try to not move the motor shaft and keep note of the position of the gear arms so re-installation will be easier

3) Removing white arm

Behind this arm are the two gears that typically break and are described in the BMW bulletin and I didn't find any way to get access to the black+white gears without removing this arm and further, I couldn't remove the arm without some cutting the arm's plastic pivots. If you ordered the small parts kit you have a new arm (with the spring pivots molded onto it), so "it's OK" to sacrifice the arm.

After a LOT of trial and error, I found sliding a super sharp xacto up between the arm and the plastic gear it attaches to, right at the pivot point and cutting through the plastic "pivot" worked best. You have to do this on two spots, at the lower part closest to the footwell and near the top of the mechanism, then the arm should detach. Watch out for flying plastic debris!

4) Detach black and white gears

With the white arm out of the way you should see a black gear with an arm and a metal pin ; this is attached to a metal shaft and there is a plastic indentation at the edge/center on the black gear that locks it to the metal shaft. Since this black gear likely has the broken tooth on it (mine was this way) I was OK to permanently damage the gear for removal.

I used a flathead screwdriver to permanently snap the plastic "clip" at the center of the black gear so pulling the gear off the metal shaft was easier (vs. trying to apply pressure to the plastic clip and pull the gear out at the same time, while upside down with limited mobility).

The black gear can be slid off the metal shaft and the white gear will likely fall off in the process.

Note: The white gear (which the motor slots into) has a very shallow pivot and kind of moves up/down even in place so if it seems loose to you, don't worry this is normal.

5) Read the BMW TIS (previous pages) carefully about alignment of the new gears

The BMW guide has you mark both the "tall" and "medium" teeth on both the new white + black gears, but I think this is confusing and it's better just to mark the "medium" on both gears because that is where you align them before re-installation. Essentially the medium tooth of the black gear (one tooth) has to be positioned between the medium teeth (two) on the white gear.

I used white-out on the black gear and a sharpe on the white gear and marked the "tops" but not the parts where the teeth mesh. Unfortunately, you have to keep the black+white gear alignment perfectly locked when you install this back into the AC system!

I suggest you get the gears aligned on the bench and try rotating one gear with respect to the other to see how they work and make sure you "get" how they will be when re-installed.

6) Hot glue step & why

I got the black+white gear properly meshed on my bench per the BMW TIS (medium of black gear between two medium in white gear), with gears sitting correctly leveled with the white gear behind the black slightly due to it's lip, and I added glue to the "top" side of the gears to hold them in this position. By using hot glue, I was able to transport the gears back to the AC system and install them even while upside down locked in alignment.

I experimented first with my old gear set by adding the same alignment marks (without the glue) and even taking my time using the mirror, most times the teeth ended up slipping when I tried to install them aligned. For the white gear, the motor provides the tension to hold it in place and without it, hand pressure isn't always enough to keep it from slipping a tooth as you push the black gear onto the metal shaft. Because I intentionally broke the center tab on my old black gear, I was able to try re-installation of my old white+black gears numerous times to realize I needed something like the hot glue method to maintain alignment when trying to re-install them.

7) Re-install black+white gear

After adding a dab of glue to the brand new ALIGNED gears, CAREFULLY transport back to the car and install by sliding the black gear onto the shaft (it can only go on the metal shaft one way) while carefully guiding the white gear onto it's mounting spot.

I highly suggest using a small mirror and put it way at the top of the gears (top being closest to the roof) and verify that your gears are ailgned and the glue held everything in place before pushing the black gear all the way onto the shaft (and permanently locking it place). Locking both gears in place at the same time is slightly tricky because again the white gear will want to "wander" so you may have to support the white gear with your hand as you push the black gear on.

8) Remove dab of hot glue from gears

I used a swab soaked in isopropyl alcohol on the hot glue which promotes releasing, and then used my mirror to see and curved tweezers to grab & remove the hot glue blob.

I also suggest after glue removal double-checking the gear alignment is still correct with a mirror. Because of the limited travel of the gears when the mechanism is "working" and the fact the alignment marks will move the minute you rotate the gears, it's hard to verify alignment without a mirror even if you rotate the black + white gears by hand after installation.

9) Install new arm

In the small parts kit, find the white arm that matches the one where you cut the pivots, transport it back to the car and snap it into place. I rotated the black gear so it's metal pin would sit correctly in the new white arm's track. You can also bend the white arm and get the metal pivot into the track if you skip this but I prefered to minimize bending the new plastic arm.

Note: My plastic parts kit included two different arms so obviously take a second to make sure you grab the correct arm.

10) Re-install motor

This step took me a LOT longer than expected, and takes quite a bit of patience. On the motor, on one side there is a portrusion or "nub" which sits in a hole on the plastic housing near the gears and the opposite side is the clip that you pushed to remove the motor.

You have to make sure the white "drive" gear has it's opening(slot) aligned to the motor "head" while simueltaneously angiling the motor to slot the pivot("nub") in place and then lock the clip on the opposite side of the motor. You can push the white arm up or pull it down to rotate the white gear's opening to closely match the the motor head before doing any motor adjustments.

Maybe because my black gear was broken and the gears had slipped I had to rotate the motor shaft (which is a bit hard to turn because the motor is geared) numerous times to get it to fit into the the white gear's slot.

11) Hook up GM, battery, flip ignition to on and then test the AC system. If all goes well there should be no popping or clicking. I would toggle my AC system into 'auto' and then hit the button twice more and that would get the motor to cycle. I observed the arm and motors while hitting the button to make sure all was well.

I also used ISTA-D to actuate the flapper motor, re-calibrate it and make sure everything was normal before bolting it all back together.

12) Install new air filter

The air filter is rectangular and will install so it's "wider" rather than taller. It took me more time than I'd like to admit to figure this out!!

Note: I think it's a bit easier to install the air filter before bringing the GM and plastics back, but if something is wrong and the flaps bind, I didn't want to jam it up with the filter.

I bought a Corecco air filter which marks the air flow direction but doesn't show the top or bottom of the air filter. Confusingly, the air flow text is NOT oriented to the top of the filter but the left/right side, hence my confusion when I tried to install it.

I assume that outside air is pulled in from the front/top of the car, so I oriented my filter so the arrow points from front of car to back.

Note: The Correco filter doesn't use glue the way Mann does to hold things in place, instead they use up a bit more surface area of the filter on the sides with re-enforced cardboard. I'd try to source the activated charcoal Mann filter if possible.

13) Slide L-shapped flap over air filter, make sure it's snaps into place

14) Re-install lower plastic trim

Re-attach GM to lower plastic, re-connect footwell light connector, slide and lift plastic into place and anchor with the two philips screws.

This step was more frustrating than expected, on the right side (near the wheel) there is a small "guide" that the plastic slides between, I had to re-position my panel many times before getting it lined up. On the left side there a slot in the plastic that goes into the carpet area, I couldn't get that lined up but the plastic just went "above" and seems to be fine so I left it that way.

15) Drink something to celebrate?

Again this wasn't "hard" as much as it is frustrating because of the awkward positions you find yourself in to do the job. I ended up with a lot of spare parts from the BMW kit because I only used one white arm and the black + white gears.