Removing Expansion Valve - '67

[Robert C.]

I'm new to mid-years and need some expertise.

Re-doing the factory AC on a '67. The system has been exposed for years, so all the components are being rebuilt or replaced.

I'm down to the POA valve and expansion valve which I'd like to have Classic Air rebuild.

Does removing the expansion valve require pulling the evaporator
housing off?

My understanding is the capillary bulb is "clipped" to the evaporator.

Looking at the entire housing, I'm wondering how this comes out. It looks like there is a bolt between the fender and housing (from drawing).

The shop manual shows the evap housing being seperate from the heater housing, secured with maybe a dozen small sheetmetal screws. Can.does that come apart and then I can remove the POA & expansion valve?

Any help from someone that's been there with a mid-year is appreciated !

Bob

[Jim T.]

Re: Removing Expansion Valve - '67

Robert my car is a 70 with factory air. The caprillary tube on my 70 is secured to the evaporator pipe with an insulating material that wraps around the caprillary tube securing it to the pipe. Mine was rewrapped with new insulating material in 1988 and is holding up well.

[Don H.]

Re: Removing Expansion Valve - '67

I would suggest at least pulling the evaporator cover. I found a mouse nest in my 65 (happened before I owned it). Don H.

[Robert C.]

Re: Removing Expansion Valve - '67

Thanks Jim and Don,

Last night I found an old article in Muscle Car Review written by Greg Donahue which showed the procedure. And yes, it seems it's attached
to the tube and buried in the insulation wrap.

Mouses.....in old cars.....imgine that !

I appreciate your help very much.

Bob

[Gary J.]

Re: Removing Expansion Valve - '67

Just be careful in removing the insulation from around the evaporator pipe. You may want to use a heat gun to soften the material up. The caprillary tube is held in place with a clamp and a phillips head screw. Once the insulation is removed you'll see how to disassemble it.

If you are going this far you may as well take the evaporator core out and have it check and have new seals put in. Doc Rebuild has a kit.

Gary Jaynes

[Joe R.]

Re: Removing Expansion Valve - '67

Hi Robert:

I rebuilt my 67 AC last winter. If you want, you can remove the expansion valve without removing the evaporator assembly. The capillary tube goes to a bulb that is clamped to the outlet pipe of the evaporator, and this junction is wrapped in insulating material to improve the thermal coupling.

The 1967 expansion valve has a unique "J" shaped bulb that is not currently reproduced, so it is probably worth having it cleaned and tested to see if you can keep the original.

If your system has been open for a long time, it is hard to decide what to rebuild and what to leave in place. The expansion valve, the POA valve, and the evaporator itself are all candidates for internal corrosion. So is the condenser and of course the dryer and compressor.

I decided to remove everything and either replace it or have it rebuilt, but that was a conservative approach.

The entire evaporator assembly, with the expansion valve and the POA valve attached, can be removed as an assembly and rebuilt on the bench. It is attached to the firewall with about 20 small screws, some of which are extremely difficult to get at. In concept the process is quite simple, but you need patience and dexterity to get all those screws out and then back in again.

If you do remove the entire assembly, you can rebuild it on the bench or send the entire assembly to Classic Auto Air.

By the way, just as another poster mentioned, I found a mouse nest in my evaporator. The mice had even chewed up the rubber foam insulation on the inside surface.

[John C.]

Re: Removing Expansion Valve - '67

Joe,
I have to assume you did this with the engine out, true?

[Joe R.]

Re: Removing Expansion Valve - '67

Joe,
I have to assume you did this with the engine out, true?

Hi John:

I did the job with the engine in place. As I recall, the engine itself was not really in the way. I did have to remove the expansion tank, the heater hoses, and the AC hoses first.

What made the job tedious was that many of the 20 or so hex-head screws that hold the evaporator assembly in place are hard to access. It was hard getting them out and even harder getting them back in.

If you install new foam rubber insulation as I did, this insulation must be compressed in order to get the screws started during re-assembly. It was difficult to apply enough force to compress the foam while simultaneously starting the hard-to-access screws. I had to fool around with the arrangement and trim some of the foam rubber to get the system back together.

I managed to get the job done, but I hope I never have to do it again. The job doesn't require a lot of mechanical expertise, just patience and dexterity.