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740 A/C evaporator loose within cover but can't remove it

Billh

Member
Joined
May 6, 2005
Location
SoCal
A/C evaporator loose within cover but can't remove it, got out & back in

I'm trying to replace the A/C evaporator as part of resurrecting the all original A/C system in my '91 745T.

I've removed all 11 screws and have partially pried the lower cover away from the upper. I can push it down 3"-4" along the front edge. The side edges taper to a small separation at back. The back does appear to be separated from the upper cover. The cover was a very tight fit at the bottom rear which I assume is the reason the back has not separated more. I've cut the sound deadening material and peeled it away, pulled out a small foam/rubber piece that was wedged between the cover and what I'm calling sound deadening material and disconnected the drain hose from the cover. This loosened the cover a little bit and I can wiggle it left/right but it will not move forward. I'm reluctant to push it further downward because I don't want to break it. Although at this point...

The evaporator has been disconnected. It can be moved left/right easily within the cover. It can be pried downward but as I'm using the upper cover edge as a pivot point I've limited downward pressure. I've hooked two large picks around the end of the evaporator and pulled. When pulled it moves upward and it sounds like it is hitting something. It will not move forward. I used a piece of wood and a hammer to see if the connection tubes sticking into the engine compartment could be moved. There was some movement as the tube ends looked like they were sinking into the foam. I stopped when one of the tubes looked bent.

Information and/or suggestions from anyone who has completed this repair will be greatly appreciated.
 
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Update: While looking/feeling around perimeter of cover I found another screw. After much slow turning one flat at a time I got it out. Lower cover can be tilted downward at front about 5-6" now. But it still seems to be jammed/stuck at bottom rear right corner.

The evaporator is as before. I have not been able to move it forward.

Hopefully someone can offer help.
 
Update 2:

Re removal - I finally was able to loop a rope around the aluminum return tube and yank on the evaporator. It came loose. I found the 12th and 13th screws holding the cover. The 13th is in a horizontal position at the rear. Got the lower cover & evaporator out. The only thing found that might explain the difficulty of loosening the evaporator is one of the tubes had a large glop of the sticky sealant that may have held it in place.

Installation - I could not follow the green book info that stated one should place the evaporator in the lower cover and lift into place. I could get the evaporator into place and I could get the lower cover into place with difficulty but I could not install them together. The evaporator goes in straight upward. The cover has to be angled, tilted, etc.

I placed the evaporator into position and used packing tape to hold it. Tape ran from underneath the evaporator to the upper cover.

The lower cover was difficult to install without the evaporator in place. To help ease the installation: more of the sound deadening material was sliced and bent out of the way below the drain hole; the 4" vertical edges of both the upper and lower covers at the rear were sanded to create beveled edges (the intention was to help the lower edge slide past the upper edge because that seemed to be one location the hampered the installation); the right side perimeter edge of the lower cover (above the blower motor section) was sanded to try to minimize the tendency of the cover to get stuck against the sound deadening material there as it was lifted into position.

All of the seemingly hundreds of wires that came into and out of the area of the removed ECU were in the way. I used cord and bungie cords to move them out of the way. I moved them as much as I dared to provide as much room as possible for the lower cover to slip past.

Last thing was the use of a 10" x 10" piece of aluminum flashing taped into position near the drain hole and on top of the folded carpet and sound deadening material. This was done to provide a smooth surface for the lower cover drain to slide on as it was moved into position.

I don't know how much each of the prep steps helped but the cover was moved into position with almost none of the previous difficulty. When it was about 1-1/2" below the upper cover, the tape was removed and the cover was lifted into position and the screws installed.

With that step finished I have moved into the engine compartment and have begun dealing with the hoses. I have some questions about those items and will be posting them.
 
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