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Old 08-17-2016, 10:39 AM
Demothen Demothen is offline
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Join Date: Nov 2015
Posts: 684
Fortunately, a forum member has offered me a Seimens housing, so I will hopefully be able to use that unmodified, rather than adapting the Behr housing to fit the evap I have.

I did take some comparison photos and did some preliminary test-fits of the new evap in the Behr housing, and came up with a rough plan that might work, should anyone need to make this modification. Here's a few comparisons of the two evap designs, as well as a preliminary idea of what would need to be modified.

The new Evaporator (Part 123-830-14-58) is very similar in dimensions to the old evaporator (Part number not known), except that the port location is slightly different, and it is roughly 1/2" thicker in one dimension. It seems to fit the Behr housing, except for one area near the ports where the fins are interfering with the housing, which would require a small area to be cut out and new plastic to be added to enclose the part. I've drawn a rough idea of the area that would need to be trimmed on the housing in gold marker. I suspect the parts (not shown) that capture the tubing to the input/output ports would need modification, although that was primarily sealed with some sort mastic or similar sealant.

My biggest concern with making these modifications is ensuring that there's adequate and even airflow around the evaporator. The new evaporator is slightly larger, which should help with cooling capability, but I'm not able to model the airflow to ensure that it flows evenly through all parts of the evaporator.
Attached Thumbnails
'85 w123 Complete AC system rebuild-evaps-1.jpg   '85 w123 Complete AC system rebuild-evaps-2.jpg   '85 w123 Complete AC system rebuild-evaps-3.jpg   '85 w123 Complete AC system rebuild-evaps-4.jpg   '85 w123 Complete AC system rebuild-evap-housing.jpg  

'85 300D - federal spec, built in late 84. 85 300D Complete AC System Rebuild
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