66 Monaco Wagon Rear A/C Unit - Need Info

[TxDon]

My wagon has the optional roof mounted rear air conditioner unit. I am going to attempt an R134A upgrade on the whole system and the shop tells me part of that will be flushing and replacement of the expansion valves, the FSM says there is one on the rear evaporator. My main question is what is involved in uncovering the unit to allow access? I can see the two side plastic trims are held with screws but how is the main cover removed? If anyone has done this let me know what is involved, pictures would also help. Thanks in advance!

 

[Polara_500]

Somebody just did a thread on the same thing on his car. Can't remember who it was though.

 

[Davea Lux]

My wagon has the optional roof mounted rear air conditioner unit. I am going to attempt an R134A upgrade on the whole system and the shop tells me part of that will be flushing and replacement of the expansion valves, the FSM says there is one on the rear evaporator. My main question is what is involved in uncovering the unit to allow access? I can see the two side plastic trims are held with screws but how is the main cover removed? If anyone has done this let me know what is involved, pictures would also help. Thanks in advance!

View attachment 188121

View attachment 188122

www.mymopar.com has the '70 Chrysler service manual on line for free download. (Tools and reference section) Not sure what year yours is, but the '70 unit looks real close. The cover is held in place by screws, there are 11 of them on the front cover and some more on the back one. Once you get the covers off, you can access the expansion valve. Extreme care should be taken in removing the valve because after 45+ years, many of them have seized threads and this will result in something on the evaporator getting broken. The roof mount evaporators are hopelessly out of stock at this point and mostly unavailable. Might want to let the shop tackle that aspect of the repair.

Dave

 

[CBODY67]

My suspicion is that all of the roof-mounted rear a/c units are pretty much the same, behind the covers. Possibly some different mounting brackets to accommodate the "slab" or "fuselage" roof contours, but the guts would probably be very similar, if not the same.

Seems like the '66 Chrysler service manual has a big section devoted to the rear a/c itself. Graphs of cooling vs. humidity, with the use of a sling psychrometer to measure the relative humidity inside the car. Seems like there are plenty of pictures of the unit itself? Ad a side note, the GM Suburbans and G-vans use an expansion valve at their rear a/c units. Not sure if the R-12 items and the R-134a items are the same or not. Never thought to look, back then. I suspect the systems are plumbed similarly, using similar methods to tie into the front systems? Not sure what specific "guts" were in the G-van upfitters' rear heat and a/c systems that were roof-mounted, but over the rear doors rather than mid-vehicle as the Chrysler units were. My point is that should something break (in the valving units), there might be some non-OEM Chrysler items which might be adapted which are new and calibrated for R-134a gas.

Please keep us posted on your progress!

CBODY67

 

[TxDon]

www.mymopar.com has the '70 Chrysler service manual on line for free download. (Tools and reference section) Not sure what year yours is, but the '70 unit looks real close. The cover is held in place by screws, there are 11 of them on the front cover and some more on the back one. Once you get the covers off, you can access the expansion valve. Extreme care should be taken in removing the valve because after 45+ years, many of them have seized threads and this will result in something on the evaporator getting broken. The roof mount evaporators are hopelessly out of stock at this point and mostly unavailable. Might want to let the shop tackle that aspect of the repair.

Dave

Thanks Dave. I downloaded the 70 manual and it does have one illustration of the rear a/c piping but no detail or instructions on how to remove the unit cover. The unit in my car is a one piece padded housing with no removeable covers except the four air outlets. I can remove the plastic pillar covers at each end but I doubt that will expose an expansion valve. I will try that tomorrow.

 

[TxDon]

Somebody just did a thread on the same thing on his car. Can't remember who it was though.

I did a search before starting my thread but nothing came up, I would love to see it!

 

[Polara_500]

It was a minor part of what he's been up to, around about page 17 or so. 73 Monaco wagon

 

[CBODY67]

From the jholst.net Chry 300 Letter Car website . . .
-- Parts book illustration of the rear unit
-- Service manual a/c service info, unfortunately none specific to the rear system per se
-- Service manual "Specifications" section for good measure
ALL are for 1965 Chryslers, so they might be a little closer to your '66 Monaco than the '70 service manual/parts items.

To enlarge downloaded graphics, put cursor near top of image and left click. On top tool bar, click "+" until page is large enough. That size should remain constant as you scroll up and down in that downladed section.

CBODY67

 

[TxDon]

It was a minor part of what he's been up to, around about page 17 or so. 73 Monaco wagon

Thanks for the link, his photos were very helpful and I subscribed to his thread.

 

[TxDon]

From the jholst.net Chry 300 Letter Car website . . .
-- Parts book illustration of the rear unit
-- Service manual a/c service info, unfortunately none specific to the rear system per se
-- Service manual "Specifications" section for good measure
ALL are for 1965 Chryslers, so they might be a little closer to your '66 Monaco than the '70 service manual/parts items.
CBODY67

Thanks, great info, the parts book illustration is very good.