[200q20v] BTDT: Step by step Diassembly/Reassembly of Heater Box (Very Lon g)

[Forhan, Thomas]

(Chris - I'll have pictures scanned by this time next week)

Its done, and operational. Here are the details from my notes.  Left is
driver's side, right passenger's, front is front of car, etc. The following
assumes you already have the heaterbox out of the car, on a nice well
lighted workbench. It is sitting on its bottom, with the fan assembly
(front) towards the edge of the bench.

1) Remove the three Phillips screws holding in the white duct next to the
fan motor skirrel cage, and then remove the duct.
2) Remove the fan motor by taking off the split ring (I used a Channelock
#904 lockring tool) and the large flat washer which hold it in the box. Grab
the squirrel cage fan and pull the whole assembly out. Check the brushes for
wear, mine were in very good condition with the springs almost fully
compressed.
3) Remove the white flap motor cover on the left side of the box, which is
held by five Phillips screws.
4) On the right side of the box, I used a pencil to mark the relative
position of the various levers. I think this is actually unnecessary as you
do not have to disassemble these levers, but it definately made me feel
better.
4) Back to the left side: remove the three screws holding the flap motor,
pull the grommet protecting the motor's wires off the side of the white box,
and remove the motor itself, lifting it very carefully and rotating in about
180 degrees to disconnect it from the two part white plastic arm which
connects the motor to the flap. You need to line up a pin/slot combination
and it will come right off- not obvious unless you look under the motor.
5) This when I stopped to look, take notes, photos, and figure out how the
heater box works before further disassembly. First, note that the little two
piece arm you just disconnected the flap motor from goes to the "control
flap", as its called in the ETKA. If you move the control flap levers,
you'll see that the levers on the right side of the box take the motion of
the control flap and rotate two other flaps. The Bentley, which I don't have
right here, numbers all the flaps, but for this job just think: 1 control
flap and 2 secondary flaps that work together. Now, looking at the back of
the box, you can see that the two vacuum servo units control another single
flap each, there is no interconnection with other mechanisms. So the box has
a total of five flaps: the control flap and two secondaries controlled by
the flap motor, and the two flaps at the back, each controlled by a vacuum
servo.
6)Remove the two piece arm from the control flap by removing a screw and a
little clip. You can see that it is keyed to line up correctly. I think it
is very difficult to reassemble the control flap/flap motor connection
incorrectly. Note that the control flap extends further outside the
heaterbox than any of the other flaps on this side. Later it will serve to
start lining up the two halves for reassembly.
7)Remove approximately 10 little spring clamps that keep the two halves
together on the centerline. Most are obvious, but look carefully around the
vacuum servos- there are two that are hard to see, one above and another
below the servos. 
8)Remove three Phillips screws that hold the inner portion of the two halfs
together. There are accessed from the left side of the box. One is obvious,
back near the fan motor. The second is down the very deep rectangular hole
that was covered up by the flap motor. You'l need a very long Phillips #2
head for this, its about eight inches down. The third is deep down another,
smaller hole vaguely the size of a nickle, behind and maybe up a bit from
the flap motor area.
9) The box will now split easily. With the unit on its bottom, front facing
the edge of the bench, gradually pull the two sides apart. Once I had all
the screws and clamps, there was very little resistance. You will find the
lefthand side will bring one vacuum servo controlled flap with it, and the
other four will remain with the right side.
10)I used a exacto blade to start cutting out the silicon sealant that holds
the heater core in, then starting digging with an old screwdriver. After
getting the old unit out - a bit of a struggle- I cleaned up the area, and
installed the new core. You really fill a large area with silicon- you are
not just laying a bead, you are filling a void. I let it cure overnight
before starting to put the two halves of the box together. 
11) Assembly is tricky. You need to get the ends of the five flaps into the
corresponding holes on the opposide side of the box. The Bentley suggests
using a template, but the thought of it gave me a big headache. Set the two
halves next to each other, again, with the front toward the edge of the
bench. For the five flaps, I used three easy techniques:
11a) The vacuum servo flaps have sort of a channel they ride in, on both
halves. One flap seemed properly positioned, but the the other (sory, can't
remember which one) was kind of drooping down. I found that if I rotated it
at the servo spring, it "assumed the postition", and so I jammed the sping
to hold it straight with a broken pencil.
11b) The control flap controls the reassembly process. I reinstalled the
screw that retains the two-piece arm and clip, but without those pieces, and
tied a two foot or so piece of string to it, and lead the other end of the
string through the proper hole on the left half. That way, as the two halves
came together, I could pull on the string and get the end of the flap
through the hole.
11c) For the two secondary flaps, I made up loops from 2 foot pieces of
string and put each loop around a flap, with the other end of the loop
draped over the top of the right hand side of the box.
12) I brought the two sides together, mostly moving the left side. You can
reach down with your fingers to help with alignment until they don't fit,
after than you pull on strings. First get the control flap into the other
side, pulling on the string to get the screw, and then the end of the flap,
through the hole. Check the two servo flaps, they are the easiest but see
that they are pretty much aligned. Then press the sides together again, and
close the gap to just a string width plus. Now, use the two loops to pull
the secondary flaps into position, looking for the ends with a flashright
through the holes on the left side. Once you have both set up, cut the
strings and pull them out. Put a couple of clamps on the box. Going back to
the vacuum servo flaps, I pulled the pencil and moved the flaps at the
springs back and forth a bit and the ends, previously just visible, popped
into place. 
13) The rest is very straightforward. Put the three screws back in, then the
rest of the clamps. Reinstall the two motors, white duct, and wrap it up.
Installation into the body was much, much easier than taking it out. I
placed it "about right" from on top, and then went to the interior and
pulled down on the servos and it all popped into place. Put the corrogated
rubber junction in place on the heater box before intalling it. Another
trick was to compress the split black duct (between the white duct on the
box and the A/C unit) into the white duct, and then pull it out into place
once the box in position.11
14) Put it all together. I tested the work before I closed off the sides of
the console and the weather cover over the heater box.

Good luck- this was a long haul for me, I hope these notes make your efforts
much shorter!

Tom F.
March 11, 2001