WILTON'S 124 EVAPECTOMY OF JUNE '08 - MINOR "STICKING" POINTS & SOME TIPS
PREPARATION/PLANNING:
I spent at least two weeks preparing and planning for the operation. I
obtained the MB service CD's, divided the job into manageable sections such
as, speakers, glove box, duct registers/vents, instrument cluster, under
dash panels, master/ignition switch/lock, lower center console, ash tray,
radio, climate control, upper console switches, console side panels, console
carpet, etc. Any large project is really done ONE step at time, whether it
be working through a calculus problem, building an engine, building a house,
a Boeing 747, a space shuttle or an aircraft carrier, it's done ONE step at
a time. This is certainly no different - it's merely a little more than the
usual amount of VERY SIMPLE stuff. I looked up the appropriate jobs on the
CD, printed them out and built a sizable book of instructions and info about
the undertaking. The CD's, though, are not designed to give complete,
detailed procedures for R&R. Quite the contrary, they're actually very
brief, and seem to be designed more for the experienced MB technician. I
also found lots of good info on mercedesshop.com and, of course
"conversations" with the very knowledgeable guys on okiebenz.com to fill in
lots of details not found in the CD's. From these two additional sources I
added lots of printouts, including photos, to the notebook. Several
extensive searches on mercedeshop.com (now peachparts.com) were very
productive. Some VERY helpful sections of mercedesshop.com (peachparts.com)
were Shop Forum, DIY Articles, and DIY Links.
Peachparts.com/Wikka/W124Stereo and "Instrument Cluster Removal", and the
Shop Forum article "124 Dash Removal (Sans Photos)", and many others were
very helpful. By the time I actually started the disassembly, I was very
well prepared and had very few surprises throughout the operation. Those
few were VERY minor in nature. A plus for me, of course, was that I didn't
have to hurry - no job to go to, no deadline and another car in the yard.
TOOLS:
Other than three very simple tools I made or modified, all of my tools for
the operation are the common tools I've used for many years: Small to
midsize flat screwdrivers mainly for careful prying, small to midsize
Phillips screwdrivers (at least 1 with magnetic tip), ice pick/awl, 1/4"
ratchet drive handle with short and long extension shafts, 8 mm and 10 mm
sockets for 1/4" ratchet, 1/4" screwdriver-like nut driver, 8 mm and 10 mm
box end and open end wrenches, needle nose pliers, channel lock pliers,
knife or diagonal cutters mainly for clipping tiewraps/zipties, butter
knife-like tool for releasing side panels on center console,
tiewraps/zipties to replace several cut during disassembly and to secure
several wires etc., out of the way for re-insertion of box, two instrument
cluster extraction tools (same tool extracts radio front - my extraction
tools made from coat hangers worked great), flashlight, 3 or 4 ziploc bags
for screws/nuts, masking tape (painter's blue tape may be better - my
masking tape was too good; 'tough to remove), rag/towel to protect steering
wheel and column during inst cluster extraction, several (~6) small bottles
of different bright color artists or modelers paints with small brush (don't
spill paint in car - I did not, BTW - JUST DON'T!), paper towels, digital
camera.
HOMEMADE TOOLS:
I made two instrument cluster extraction tools from coat hangers: on one end
of a piece of coat hanger about 8" to 10" long, sharply bend a 3/16" length
of it at 95 to 100 degrees to the main shaft; form a circle on the other end
big enough to grasp and manipulate the tool well.
Rivet pin insertion tool: Another tool I made/modified helped make
reinsertion of several plastic rivet pins for actuator rods on the
evaporator box very easy, a very simple job that was much tougher with
regular pliers, etc. I taped a 10 mm hex nut to the inside of one jaw of my
channel-lock pliers near the outer end of the jaws. I simply placed the
base of the nut against the inside of the jaw and wrapped a piece of masking
tape around the jaw and nut to hold the nut in place, then punched a hole
through the tape into the hole in the nut. This made a very simple
pliers-type tool to press the rivets in place by allowing the tip of the
rivet to go into the hole in the nut as I pressed the pin in place with the
other jaw of the pliers pressing against the other end of the rivet pin.
Console sides removal tool: MB service CD job 68-205 describes an
extraction/release tool for the clips between the console carpet and the
plastic sides - a metal bar 30 mm wide, 2 mm thick, 135 degree bend at one
end, 120 degree bend at other end, etc. I made a tool from a butter knife
(wife doesn't know yet. BTW, I used a stainless steel one, not a silver
one) by bending the handle to about 135 degrees. I could grasp the handle
with channel lock pliers or vice-grips to aid its work as necessary.
RADIATOR:
I did NOT drain the radiator; 'merely disconnected heater core hoses just
forward of the firewall; 'lost maybe half a cup of coolant. 'Sealed open
ends of heater core pipes with masking tape before moving evap box; make
sure these ends don't drip coolant where not wanted. 'Had to remove battery
to get to the hose clamp behind inner, rear corner of the battery.
STEERING WHEEL:
I did NOT remove the steering wheel, either; 'just ran it full out and put
front wheels straight ahead to have flat part of the steering wheel spoke on
top to allow inst cluster clearance.
DASH DUCT VENTS/REGISTERS:
The spring clips holding the dash air registers/vents in place are easily
released by prying inward (upward on the lower ones and downward on the
upper ones) with an ice pick or an awl. Each of the clips (four each on the
side vents and 2 near left end of the center vent) snaps into a detent in
the dash. Slip an ice pick or awl into the small hole in the part of the
clip protruding into the vent/register just inside the louvers and pry up or
down to pull the clip out of its detent. You have to pry on one then
another, but it helps if you can do two of 'em at the same time while
pulling outward on the register/vent. I was able to pull one side of a vent
out a little way and then the other side till all the clips were released to
easily extract the register/vent. The Allen wrench for the screw in the
middle of the center vent on my 124 is 4 mm, not 4.5 mm as reported by some.
An Allen wrench with T handle from HF worked very nicely. The Center vent
also has a Phillips screw in its right end accessible in the glove box
opening.
INSTRUMENT CLUSTER:
I had a REAL problem getting the inst cluster to slip out; the two rubber
pads on the underside of it and two on top of it would NOT SLIP along the
inner surface of the hole in the dash to allow me to extract the cluster. I
was able to apply PLENTY of extraction force. I had firm grips on both
sides of the cluster with my extraction tools about 3/4" down from the
curved, upper corner on each side or about 2 inches up on the sides from the
bottom corners - the cluster WOULD NOT MOVE. I was finally able to move the
cluster after I pushed the blade of a 2-inch-wide putty knife beneath the
cluster and pushed one of the rubber pads out of place toward the front of
the car. I then reached in from the underside and removed the pad with
channel-lock pliers aided by a mirror and feeling with my fingers. After I
removed the cluster, I found some factory glue on the outside of it that had
overflowed or squeezed out of the dash and insulation. This glue and the
stuck rubber pads held the cluster fast enough that I had been unable to
move it normally.
Before unplugging wires on the instrument cluster, I color-coded them with
different color paints - the small lamp sockets across the bottom right of
the cluster are all alike and can be easily plugged into the wrong socket on
re-assembly. Before re-inserting the cluster, make sure all the bulbs are
secure in their sockets - not loose.
DASH SCREWS/NUTS/CLIPS:
The dash is secured by one 8 mm hexhead screw by each speaker (under the
speaker grille), 2 Phillips screws inside and beneath right side air duct
register/vent, 2 10 mm nuts at under-edge of dash at top edge of center
console, a Phillips head screw at left end (outside of headlight switch and
covered by the under-dash panel)and several 8 mm and Phillips screws
between under-dash panels and the dash. A screwdriver-type nut driver with
a 1/4" X 8 mm or 10 mm socket attached makes removing the screws easier and
faster. I put masking tape over spring clips along the lower edge of the
dash to keep them in place for ease of re-assembly ('course to keep from
loosing 'em, too). Don't forget to also secure the clips on the left end of
the dash beside the light switch.
CENTER CONSOLE:
The group of switches on the lower center console behind the gear shift
lever is secured by two Phillips screws along the forward edge of the group.
Remove these two screws and slide the group slightly rearward to release 2
clips at the rear edge. You don't need to remove wires from these switches.
When removing the center console sides, turn the group of switches askew,
etc., to leave them approximately in place on the tunnel as the console
sides are removed upward and rearward.
I used an instrument cluster extraction tool (coat hanger hook) to easily
remove the front of the radio. Insert hook end of the tool at upper right
corner of the tape door with the hook tilted to the right so as not to
interfere with the pushbuttons. Pull carefully but firmly and the front of
the radio comes unplugged and comes off. With the front of the radio
removed, a black plastic clip is visible at each lower corner of the radio.
Using a flat screwdriver, pry downward on the clips to release the radio and
slide it rearward. To facilitate re-assembly, I dabbed different color
paints on the radio plugs and receptacles. All the plugs but one are shaped
differently and will go only one place, but one small clip will go TWO
places. After all the wires were unplugged from it, I grouped them all
together and put a piece of masking tape around them.
After the radio is removed, the wood panel around the climate control and
upper switches can be removed by unscrewing two Phillips screws in its lower
edge above the radio. Lift lower edge of the panel up and unclip/unhook its
upper edge with slight downward pull.
The climate control unit is secured by six Phillips screws. Not knowing why
it has so many screws and if they were all the same or not, I color-coded
these with paint, also. Actually, two of them ARE shorter than the others,
and I didn't investigate why - 'just put 'em back where they were. The
climate control has two identical rectangular plugs that were hard to get
released/unplugged at first. I also coded these with paint. 'Was able to
slowly get them unplugged by carefully prying around their edges with a flat
screwdriver. Also on the lower left, inner/forward corner is a spring metal
clip that protrudes up under the climate control box - this may be some type
of grounding for the radio - the top of the radio case contacts it when
installed. Make note or remember where and how this goes - don't forget it
during re-assembly.
Reach in behind the top row of switches and remove the plastic protective
cover on the backside of the wire bundle behind them. This gives the row of
switches room to move toward front of car for removal. Pull the top 1/4" or
so of the left-most switch off - it just unplugs; then push forward/inward
on the left side of the row of switches and push the entire row of switches
left to unclip the right side from its support. Work the row of switches
free of the console. Leave the switches plugged in to the wires and pull
them aside. I wrapped a rag around my row of switches, securing the rag
with masking tape. After getting that row of switches out of the way, you
have access to the two 10 mm hex nuts securing the dash to the center
console directly above the switches. Remove the nuts and leave the two
bolts in place - remove console side pieces before dash - it slides to rear
with slots clearing the bolts. The heads of the bolts are secured to the
dash by spring clips. Secure the clips and bolts with tape.
The rearmost end of the center console is secured by a single, long Phillips
screw under the carpet at the rear of the tray. Pull the piece of carpet
out to access the screw. The console sides are clipped onto four pieces of
thin fiberboard "tongues" that protrude upward from the carpet backing on
each side of the tranny tunnel. Two of these tongues are visible and
accessible immediately forward of the group of switches just to the rear of
the shift lever. The other two tongues are visible inside the console sides
an inch or so rearward of where the console turns upward toward the dash. By
sliding the butter knife-like tool described above up under the lower edge
in the appropriate places at the tongues and prying at them at the same time
with a brake adjusting tool I've had for fifty years, I was able to release
these tongues. Pull the console rearward and upward while twisting the
group of lower switches to pass through the opening as the console is
removed.
Each side carpet on the console is attached by a screw horizontally into the
tranny tunnel at the side of the foot wells. Most of the carpet has a thin,
stiff, fiberboard backing, but several places around the edges also have a
very sticky, goopy glue that never hardens. Take care in storing the
carpets temporarily - make sure they're stored so that the glue doesn't get
on something it shouldn't, such as other carpet, etc. BTW, the glue will
run and drip over time, especially in a car sitting in the sun.
MARKING/CODING WIRES & VAC TUBES; ORGANIZATION OF SCREWS/NUTS:
I used several different colors of artist acrylic paints to mark/code
electric plugs/receptacles, terminals, vac tubes, etc., before disconnecting
anything to ensure rapid, accurate re-assembly. I kept screws/nuts
separated in labeled ziploc bags by system, i. e., glovebox, dash,
under-dash panels, center console, etc. (I used only 4 bags, though) Some
screws I even taped to the appropriate part or wrapped them in labeled tape.
I started out using sticky-back paper labels on some wires, etc., but
quickly realized they were coming off. 'Switched to masking tape, but
'turned out, the tape I used was too sticky and too tough - 'was a hassle to
get off during re-assembly - I even left some pieces on. One should
experiment and find a tape with appropriate durability for the job before
starting - painter's blue tape may work well.
ELECTRIC WIRES/CABLES & VAC LINES ON BOX:
Disconnect the two sets of electric wires on a two-terminal bus on a small
plastic block beneath the front, middle of the box immediately on top of the
tranny tunnel and beside the bracket that secures the bottom of the box to
the tranny tunnel.
I couldn't disconnect the elec plug on the left side in the middle of the
box 'til I had cleared away stuff immediately to the right of the steering
column and pulled the box out a little way for better access to it. The
clips on the plug assembly would NOT release in the normal manner by
squeezing; 'finally got to it with both hands and pried hooks loose with
small screwdriver one side at a time. 'Also had to pause extraction to go
around to driver side of engine by brake booster and push blower motor cable
and grommet through firewall. 'Probably better to go ahead and poke the
wire and grommet through the hole when you unplug it on front side of the
firewall immediately behind and above the brake booster. I had a problem
getting this plug loose for a few minutes. I thought it would unplug by
pulling it straight toward front of car. During my frustration with it, a
friend came along and asked, "Whatcha doing?" I quickly told him about the
evapectomy, etc., and asked him if he could unplug that wire up under there
for me. He glanced in, reached right up under there with his left hand,
squeezed the releases on each side of the plug and deftly lifted the plug
UPWARD, and, voila! 'Twas done in a flash.
You have to disconnect only ONE vac line to remove the box - a green one
that runs across top, front of box and connects to top of switchover valve
mounted on right side of box.
A sensor in the right side of the area above the blower motor and just
forward of the firewall must be removed during extraction. Leave it exposed
and obvious so you don't forget to plug it back in during re-insertion.
CLEAR PATH TO RIGHT OF STEERING WHEEL COLUMN:
You have to clear EVERYTHING out of the area between the steering column and
the evap box to clear a path for the heater core pipe, Freon pipes,
expansion valve and the large grommet around the Freon pipes to go in and
out. I was able to pull everything up and to the left and lay it on top of
the large, heavy brace for the steering column - that's the master/ignition
switch/steering lock assembly, wires, electronic boxes, etc., moved left and
up out of the way.
To remove the master/ignition switch/lock assembly, loosen from the
underside the bolt that tightens a collar around it, turn the key to
position one (key must be absolutely and positively in position one) and
depress a small pin in the backside of the assembly toward the driver. With
the pin depressed, the assembly comes out with some twisting and working
with it to clear left side of the evap box, etc. This area of the box has a
rubber membrane area to accommodate removal of the lock assembly.
EXTRACTING BOX:
My evap box came out much easier than I was expecting. I had read reports
of others having to pry theirs loose because of sealant around it at the
firewall. My box came right out with no prying.
When moving the box backward out of the firewall hole, take care not to
catch a wire along the top of the tranny tunnel with a protrusion on the
bottom of the box. You have to pause during extraction and make sure the
blower elec cable is free of the firewall and coming with the box. At this
time, also unplug a probe (sensor) in the right side of the area above the
blower motor and just forward of the firewall. Make sure you leave this
sensor and cable exposed and obvious so you don't forget to re-insert it in
its mounting bracket during re-insertion.
DISASSEMBLING EVAP BOX:
Disassembly of the box is very simple and straight forward - the CD
instructions are easy to follow, EXCEPT AS NOTED IN THE WARNING/CAUTION
PARAGRAPH BELOW. The small spring clips are removed very easily by prying
with a flat screwdriver or gripping with needle-nose pliers; don't let 'em
fly away. Several Phillips head screws must also be removed. Keep the
clips and screws "safe" to ensure their availability for reassembly
WARNING!!!!! CAUTION!!!!
The bottom of the box has a metal, horizontal rod that operates flapper
valves to the floor ducts on each side of the tranny tunnel. The right end
of this rod has a weak spot consisting of two small pieces of thin plastic
at right angles to each other - this link will easily break if over-flexed
or pulled excessively. Written instructions and a drawing at the bottom of
page 4 of job 83-554 in the MB service CD say, "Pull right side (of the box)
out slightly and unclip joint for leg room flap (arrow)." But this creates
a danger of breaking the fragile, plastic, hinge area of the rod on the
RIGHT side. It's much easier and safer to reach up inside the duct on the
bottom, DRIVER side - the LEFT SIDE - of the box and pull the short, split
rivet-type pin in the LEFT end of the horizontal rod FIRST, and re-connect
it after the side pieces are back in place - much easier and much less
danger of breaking a fragile HARD-TO-REPAIR plastic hinge area.
FITTING EVAPORATOR IN BOX:
My new evaporator had a thin ('bout 1/8 inch thick) foam pad across the top.
With this thin pad in place, top half of the box would not fit with bottom
half properly. Original evaporator didn't have the pad, so I took it off.
Top and bottom halves went together well after the excess pad was removed.
SPRING CLIPS ON OUTSIDE OF EVAP BOX:
Take care when pressing the little spring clips (1/2" X 1/4") back in place
on outside of the box. I lost one when my thumb slipped while trying to
press the clip in place. The clip flew, and I thought I heard it hit the
floor; 'found it days later in cargo area (canvas bag) of my walker. 'Used a
tiewrap/ziptie in its place.
RECIR/FRESH AIR VALVE AND ITS ACTUATOR ROD:
The thin foam on this large (about 4" X 20" roughly) flapper valve at the
top of the box and above the blower was brittle and "powdery" - could easily
blow off in fine little dust-like particles and into the passenger cabin. I
removed all of the foam with a scraper and vacuum cleaner.
Though all of my vacuum pods on/in the box were working well, I replaced
them while the box was on my workbench. If you are replacing the
actuator(vac)pod for the large recir/fresh air valve, measure the length of
the short actuator rod at the middle of it (the short rod attached directly
to approximate middle of the flapper), or tape the black plastic part of the
rod to the metal part of the rod, so it won't move while working on the box.
The plastic part of the rod on mine came unscrewed and dropped into the
blower cavity during re-assembly; 'was a hassle to fish it out and then
guess, adjust length, etc., for proper operation of flap/valve.
BOX RE-INSERTION:
Get everything in the car ready for insertion - wires, etc., tied out of the
way for a clear path to the hole in the firewall. Several plastic
tiewraps/zipties are handy to temporarily tie some wires, vac tubes, etc.,
out of the way for re-insertion, and, of course, to replace several that
have to be cut during disassembly. Just before re-insertion, apply
not-an-excessive bead of sealant on the firewall around the box hole to
prevent air leakage. During re-insertion, I had some hassle getting the
rubber grommet for the blower wire installed in its hole in the firewall.
The wire is eccentric (sloped off to one side) in the grommet making it even
harder to handle, especially with one hand. After several tries and poking
it all the way through the hole each time, I got it installed - installation
of this grommet works better from the outside (engine side).
Don't forget to mount the sensor in the right side of the area above the
blower motor and just forward of the firewall back in its holder.
'Some more jiggling, pushing, etc., to clear wires by the steering column
(really tight) and insert drain pipes in the holes above the transmission,
and I bolted the box securely in place with a nut at each corner.
CONDENSATE DRAIN PIPES:
I replaced the two four-inch-long condensate drain hoses on each side at the
bottom of the evap box with 1" ID heater hose - a perfect fit. I added
security to each hose installation by putting a ziptie tightly around each
after pushing it over the "nipple" on underside of box. 'Must be sure to
work lower ends of these hoses through holes in top of the tranny tunnel
just before final re-mounting of box to the firewall, in case you need to
jiggle the box a bit to get the hoses in the holes. Flexibility of the
rubber made it fairly easy for me to get them through the holes.
ATTACHING UNDER-HOOD FREON TUBES TO EXPANSION VALVE:
I used a 1/4" ratchet with an extension and a universal joint with a 10 mm
socket to R&R the 10 mm nut holding the mounting plate for the two Freon
pipes at the expansion valve. When I got the nut loose and began to extract
the extension shaft, socket and nut, the nut fell into the "abyss." I
didn't agonize over it 'cause the new exp valve had another nut on it, but
when I began to install the Freon tubes into the new one, I decided to
recover the lost nut. I taped a magnetic Phillips screwdriver endpiece to a
long, thin screwdriver and fished around in the abyss a bit with it, then
slowly withdrew it. Low and behold, I had captured the lost nut!
Re-installing the nut, though, I used some of that tough masking tape -
'stuck the tape to the back and sides of the nut and left a "tail" of the
tape 6" or 8" long, folding the sticky part of the tape over itself to form
a little rope with the nut at the end of it. Then I was able to get the nut
started with much less fear of losing it into the abyss. A short box end 10
mm wrench worked nicely for final tightening of the nut. A "security cord"
of tape on the wrench also helped to keep it out of the abyss.
Wilton
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