___DD. Actually did step O (pulling pipes out of expansion valve) at this point so as not to leave AC open for (albeit plugged) for as long..
___EE. UNSCREW 4 NUTS (
Pic122 Pic125 Pic127 Pic128) Bag7 AND PULL BOX DOWN AND OUT (needed pry bar to get BOX from firewall on Upper and Lower R and Lower L. Could not fit in upper Left so used vise grips to pull that side. Had to wiggle it out, pulling hard. Took 5-10 minutes.) Picture of firewall with BOX out (
Pic129). Note large wire across top of opening that has to be lifted in order to pull out and to reinsert BOX.
___FF. Replace gasket in bulkhead. Scraped off old with slotted screwdriver. Used Ace Hardware #51278 Open Cell Rubber tape 3/8” x ¾”. Worked well
___GG. REMOVE OLD SEALANT AND APPLY NEW TO BOX. Used NAPA #MS 4196 Glass Butyl Tape 3/8” x 15.
___HH. OPENING HEATER / AC BOX
______1. Disconnect all vacuum element lines (
Pic130) noting color coding
______2. REMOVE 10 CLIPS ON FRONT (
Pic131) Bag7
______3. UNSCREW 4 SCREWS ON TOP AND REMOVE COVER (
Pic132) Bag7
______4. Remove Heat exchanger 83-522 (C:\Program Files\MB 300 CDROM\Program\Climate\83-522.pdf )
_________a. RELEASE MAIN AIR FLAP VACUUM ELEMENTS by removing 3 screws (
Pic133) and releasing vacuum element from metal bar. I made mistake of removing bar from actuators and broke several connections. To repair drilled hole and tied bar to actuator with upholstery thread to keep them from separating (
Pic134).
_________b. REMOVE BOX COVER – already done
_________c. REMOVE CLIP FOR COOLANT LINE ON EITHER SIDE (
Pic135) by slipping screw driver between clip and box in 2 places for each clip
_________d. LIFT HEAT EXCHANGER (
Pic136)
_________e. tried to replace 3 o ring seals but could not get upper 2 pipes off. Gave up.
______5. Remove linkage for legroom vacuum element (
Pic137)
______6. Remove linkage from left side (via bottom) for left and right legroom airflap (
Pic138). Linkage broke on R later. Sewed it together with upholstery thread rather than waiting several days to get part (
Pic139). Amazing that it lasted this many years. On reassembly, adjust linkage so both sides open and close at same time.
______7. Remove 2 screws each on left and right of box and remove front upper housing on each side (
Pic140) Bag8
______8. Remove vacuum connection to center vacuum element on upper front box (
Pic141)
______9. UNCLIP 4 CLIPS EACH ON L AND R OF BOX IN FRONT OF BLOWER MOTOR HOUSING (
Pic142 Pic143) Bag7
______10. UNCLIP 3 CLAMPS EACH ON L AND R AND 1 CLAMP IN CENTER OF BOX (in picture 3rd clamp is above the 2 being pointed at
Pic144 Pic145) Bag7
______11. PRESS OUT CLIP (
Pic146)
______12. TAKE OUT EVAPORATOR. Note the crud in fins (
Pic147). This was already vacuumed out a few months ago which is why I suspected a evaporator leak. Also decided to suck off all the friable foam from the outside of the recirculation flap as this may be been flaking off and getting stuck in evaporator (
Pic148 Pic149). Inside foam was not nearly so friable.
______13. Remove molding around evaporator inlet and outlet (
Pic150) When replacing, added sealant to molding as there was a large gap – used removable sealant from ACE Hardware: red devil zip away removable weather stripping. Could have used another sealant. Also placed same sealant at firewall where evaporator inlet and outlet pass through gasket (
Pic159).
______14. MOVE SCREEN FROM OLD (
Pic150) TO NEW EVAPORATOR AND INSERT. For ACM evaporator pipes had to be bent slightly to get them to come out of BOX correctly. Also note that during reassembly tabs (
Pic154) on upper front of evaporator must be centered in box or cover will not go on properly. I had to slide evaporator to one side for this to happen.
______15. clean fins of heater core if necessary – it was not
______16. Replace all vacuum pods 83-665 (C:\Program Files\MB 300 CDROM\Program\Climate\83-665.pdf ) Only pods that did not work controlled recirculation. Hints below apply if BOX was not taken out of car. For all pods, remove at hub of pod rather then at distal end of steel actuator.
_________a. REPLACE DEFROSTER POD TO RIGHT OF BOX (
Pic151). Consider working on R diverter pod while defroster pod is out if working in car.
_________b. REPLACE FOOTWELL POD ON FRONT OF BOX (
Pic137)
_________c. REPLACE CENTER POD WITHIN BOX (
Pic141). This pod may be replaced without removing heater core. Remove the white pin in the top door. Remove the door by flexing it out of it's hinges. Remove the flat metal rod from the pod. Pull the hose and twist the pod out, it will *just* wiggle out from under the mounting bracket
_________d. REPLACE DIVERTER POD ON BOX COVER (
Pic152). The diverter pod is held in by 3 round metal press clips (
Pic153), so you need to break out the old one and save the mounting clips for the new pod. To press the washers back onto the new pod, a small 1/4" drive socket works well.
_________e. REPLACE RECIRCULATION POD X 2 BEHIND AND ON EITHER SIDE OF BOX AND ADJUST (
Pic133). Leave flat metal bar attached to car for recirc pod. There is a lock tab that must be pressed before the pod will rotate out. Or removal of the bracket holding the seatbelt warning relay to the left of the left recirc pod will make removing the pod easier. Also removal of the defroster pod makes it easier to remove the right recirc pod.
______17. REVERSE ASSEMBLY OF BOX but before installation verify action of vacuum pods 83-620 (C:\Program Files\MB 300 CDROM\Program\Climate\83-620.pdf )
___II. Replace receiver dryer and pressure switch and seal with Nylog 83-540 (C:\Program Files\MB 300 CDROM\Program\Climate\83-540.pdf )
______1. remove air intake cowling to provide space (
Pic155)
______2. REMOVE PLUG FROM BOTH PRESSURE SWITCHES (
Pic156)
______3. UNSCREW BOTH PRESSURE SWITCHES – not done as using new.
______4. REMOVE BOTH LINES TO FLUID RESERVOIR (
Pic157). WHEN TIGHTENING, USE 15-18 Nm.
______5. REMOVE BOTH BOLTS HOLDING RESERVOIR IN PLACE (
Pic158)
______6. Replace O rings and LUBRICATE O RINGS AND ALL THREADS WITH COMPRESSOR OIL WHEN REPLACING. Used Nylog instead.
______7. ADD 10 ML COMPRESSOR OIL FOR DRYER AND 10 ML OIL FOR LEAK TO NEW DRYER BEFORE INSTALLATION. 83-525 (C:\Program Files\MB 300 CDROM\Program\Climate\83-525.pdf ).
______8. Better to attach lines and start threads before inserting bolts holding reservoir in place.
___JJ. REASSEMBLE.
___KK. Remove black paint from condenser with acid mag wheel cleaner. May get 20% improvement in cooling. I tried one application but paint did not come off so I moved on.
___LL. PULL VACUUM THEN REFILL AC.
Pic001 to Pic005