<E34> Microfilter

["Brant M. Miller" <brant@xxxxxxxxxxxxxx>]

Peter, the Bentley Manual and other sources say the microfilter started i=
n
1992, so you should have one.

Re instructions for changing same, there has been much on the Digest over=

the years and the Bentley Manual can also help.  I've reproduced my hash =
of
good advice originally provided by Kurt Gibble and Dan Quicker below - my=

appologies to the two of them for any deteriorations I may have introduce=
d.
 Kurt had (has??) the instructions on a web site, however, I've lost the
URL.

When you are all done, you will have a new appreciation for how footprint=
s
get onto BMW headliners!

Kurt Gibble (9/91 E34 M50 5sp) provided most of the below information wit=
h
comments by Dan Quicker ('95 540ia) incorporated.  I=92ve added a bit to
reflect my experience with the microfilter on my 1995 525i.

Working somewhat from Chilton (just short of useless for this job) and
mostly
from BMW fiche: =


1) Remove glove box by removing the retainers holding the strap and gas
strut
(if present) from the sides of the glove box. Lying on the floor, loosen
and
release the latches for the rear hinges. Dan says "Glove box is now sitti=
ng
on
your head."   Just reach under the glove box and pull the snap connector
releases down.  The connectors will then slip off the mounting rod.

2) Remove the carpeted panel on left side of pass. footwell. On Dan's 540=
,
the
carpeted panel was screwed to a gray mount that is removed by pinching th=
e
mount and sliding it out. This mount would have been in the way when you
slide the filter out in step 6. =


3) Remove the black cover on left side of glove box. (On this, the fiche
has the
wrong picture in Sec. 64-31/2 but I believe Fig. 2 of Sec. 64-31/1 is
correct.)
Remove the small duct going to the RHS of pass. footwell. On the 540, the=

black cover and the RHS footwell duct should be removed as one piece. On
the '95 540 there are 4 screws and this sounds like what I remember for m=
y
'92:

     a)1 holds the top of the black cover to the dash.

     b)2 secure the duct behind the glove box hinge mounting bracket. On
the
     '92, these easily fall down in between the bracket parts - it's hard=

to
     retrieve them from there!

     c) 1 well hidden screw holds the duct directly above the 90 degree
bend it
     makes from the console to the footwell. It is on the top side of the=

duct. (On my 95, the fourth screw connects the pannel to the top of the
glove box compartment.)

Turn the assembly out of the way. (The wires to the flashlight don't have=

to be removed.)

4) On the '92 (and my 95 525i), remove the wires for the HVAC control uni=
t
(I believe that's
what it is) at very front & bottom of the console, right next to the fire=

wall.
Wires have a v nice, arguably over-engineered, connector - lift the lever=

up
and the plug automatically comes out. On my 95, the lever does NOT lift
up!!  Reach behind the lever and press the catch in.  Then rotate the lev=
er
back.  A cam will disconnect the electrical connector.

Release the clip and pull out the control unit. Dan says that on the '95
540, you
can leave the wires attached and just set the unit aside - pick your
poison. =


NOTE: Over the AC coil and heater core, there is a black cover with 7 T15=

screws. The microfilter's not under there! You don't have to remove it -
beender dunyat (see step 3 about wrong fiche picture.)

5) Down further & recessed (toward the center line of the car) is a small=

funny
shaped (tall and thin) white cover (on mine) with 1 or 2 screws (T15 I
believe).
The microfilter is under there. I think you get it loose and then have to=

rotate a
lever to get it out. =


On the '95 540 (and on my 1995 525i), Dan says the white cover is right
next to the control unit. It is
held with 1 T15 screw and a cam lock lever at the top. Loosen the screw,
Turn
the camlock counterclockwise. Remove the White cover. The filter is right=

behind it. As you can imagine, the white cover is as tall as the filter
(5"?) and
about 1 1/2" wide. =


6) Pull the filter out. While your there, clean out any junk in there tha=
t
you
don't want to blow out of the center vent and into your face. (Leave the
junk
that you do want blown into your face.) (Be careful not to damage the air=

conditioning radiator while cleaning the coils.  It is easy to mash the
fins.

7) Trivial Step: Assembly is reverse. =


Took me ~2 hours first time because of the brevity of Chilton and the err=
or
in
BMW fiche. Should be a 30-45 min job 2nd time. (Took me about 4 hours fir=
st
time.  Much of which was spent on the electrical connectors.)