Question from Norm (1963):
Does anyone know the answer to the question of whether a front and rear expansion valves for a 1963 Imperial are the same?
After tossing-off the last reply to this thread, I suddenly realized I had the answer to Norm's question right next to me.
I picked up my 1961 Mopar Parts Manual and looked in section 24 - Air Conditioning, and looked at the picture of the rear A/C unit to look for "Valve."
I found one, and looked up code #24-28-300: "Valve, Expansion, front and rear unit," for Imperial, part number 1879580, (this is a change or addition to an older model). The same part number is used on front and/or rear of all factory-installed air-conditioned Chrysler Products, including Valiant, but excluding station-wagons and the under-dash, dealer-installed "Model F".
My experience with 'air' tells me that the rate of release for the two valves would 'almost certainly' NOT, be the same. Some, or maybe all of the Chrysler expansion valves are adjustable...and can be adjusted to produce the proper balance of release. A balance between the two valves is needed to insure equal cooling front to rear.. I do not know if the front valves could be interchanged to the rear, hose hook ups ports may vary.
I don't know if this will help, but when the expansion valve failed in my 56 Packard about 10 years ago, I took one off an old aftermarket Mark IV unit that came out of a 64 Chevelle I junked out about 15 years ago, because it looked like it would fit and had the same fitting threads as the Packard.
It has always worked perfectly for me, and I have had the car in some really severe conditions, for example in southern Tennessee with both Humidity and Temperature close to 100. It keeps the car perfectly cool and never ices up, and that's all you can ask. So take the old one off (save that Freon!) and shop around for a close match. I'll bet it will work fine.
I don't know whether it's been discussed before on IML, but there are at least two books that are indispensable for working on and tracking down parts for Imperials.
- the factory service manual (FSM), otherwise known as the shop manual
This book tells about all of the procedures for adjusting, disassembling, rebuilding most everything on your Imperial, from the replacing the rear axle wheel bearings to adjusting the horn, to adjusting window glass, etc.
For 1965 and 1966 at least, the relevant FSM covers both Chrysler and Imperial.
- the parts book
This book breaks cars down into every separately orderable part or subassembly on the car. It has a lot of illustrated parts breakdowns of all areas of the car.
For 1965, this book covers "ALL" Chrysler Corporation passenger cars manufactured in the USA. From Valiants to Imperials and everything in between!
These books can be somewhat difficult to follow, for they give a illustrated parts breakdown that might apply to many, many models, along with a table that gives the part numbers for each model. For example, there might be a diagram of the transmission kickdown rod, along with a table that lists the parts numbers for A bodies (Valiant), B bodies (Satellite), C bodies (Fury), and D bodies (Imperial).
One would hope to find out in this book if the front and rear expansion valves were different. But with A/C, things may not be so straight-forward. A/C was considered to be more a kind of unusual optional equipment who's description is not integrated very well into either the FSM or parts book. For example, repairs on the dashboard fail to mention the presence of the A/C ductwork and such when describing how to access things. The parts book for 1965 has the A/C systems listed separately from the car models. It is organized something like A/C Model 914, A/C Model 623, etc. It's up to the reader to figure out which A/C system an Imperial uses. By studying the diagrams, one can figure out which applies.
These factory manuals each cover only one model year. I have both a 1965 and 1966 FSM, because the Chrysler/Imperial manual was rewritten for the new 1965 Chryslers, and the material is not integrated very well. I also got the 1966 manual, because it is written a lot better. But it is for 1966, so it doesn't apply to my 1965 in places like the transmission linkage.
There are other useful manuals, such as parts interchange manuals that cover what parts are common between years. But I think the FSM and parts book are the most useful. One might consider the price pretty steep ($40-$60 each?), but for how much time they save, they are worth it. I guess it also depends on how long one is thinking of keeping a particular car as to whether the investment is worthwhile.
I got my FSM and parts book with the help of a fellow IML member, Ed Trenn. At that time I wouldn't have known where to start... like the fact that a parts book even existed. I got my stuff at swap meets, but one could also get them though literature vendors such as those listed in Hemmings.
Before you go and replace that A/C Expansion valve check the inlet port screen - it may be plugged. The 1963 Chrysler/IMPERIAL service manual doesn't mention any thing about two different types of valves and the parts book shows it to have a code # as 24-28-300 and an Imperial part no. as 1879 580.
One day I had to do the same thing and checked out my ailing rear A/C unit. But when I got my front A/C unit working I found that the the screen inside the valve was plugged.
Question from Norm (1963):
The rear expansion valve on my rear A/C system gets cold when the rear system switch is turned on but the discharge air is not cold. Any ideas why?
Reply from Paul:
My experience on a '73 with those symptoms was that the inlet to the rear valve was clogged. I removed the valve, flushed out the crud with "Gum-Out" Carburetor spray, blew out with compressed air. After recharging it worked fine. With the Freon problem (scarcity and $$$) these days, I would not take a chance on reusing the old valve. I think a new valve is the best course of action.
As far as evacuating and recharging a system, this would remove any moisture content in the Freon. Moisture not only makes the Freon corrosive but if the moisture content is high enough, the system will stop cooling or will cool only for a few minutes when first turned on.
For reference, the '57 vintage Mopar shop manuals, (first year for in-dash units and for the RV2 compressor), have an excellent discussion about the problems of moisture in a system.
Question from Matt (1966):
I think my rear air expansion valve is bad. I am having it checked today. Questions:
1. Does anyone have a part number?
2. Are these rebuildable?
3. Source for new or rebuilt valve?
Reply from Roy:
Although I am not familiar with rear air, expansion valves are somewhat generic. While you can try to find a NOS OEM valve for show purposes, most AC reepair shops will have a part that will fit and work sitting on their shelf.
Follow-up question from Matt:
What a find I have found. My new air cond. guy really knows his stuff. The expansion valve on the rear did need replacing and he got one at our big parts house here in town! He called to tell me that tonight and also I need a new compressor shaft seal. He is looking with his sources, but if that fails does anyone know of a source for those? He said for the 134 conversion labor and parts about $70-90. How 'bout that for reasonable.
Reply from Keith:
I believe Jim Carpenter can help. I repaired mine and its working well. It had worn the inside of the seal ( the rubber part ) this is clamped tight with a steel ring around the out side. With a little help I machined a new ring a few .000" smaller and no more leek.