Re: Air Conditioned '55-'56 Packards

Posted by HH56 On 2010/1/17 11:31:58

There are two field install guides on site and the Packard one in my link is nothing like the Mark IV install which was recently posted.

The older Packard up thru 54 units had the constant belt drive and those had to be removed to prevent the compressor from turning. In 55 the Lehigh had a clutch but essentially that was just to engage when turned on so the belts didn't have to be removed in winter. Wasn't really designed for the constant cycling like modern units.

Temperature control was again hot gas bypass as with older units but this time was done by a modulator valve which was fixed at around 40-45 degrees. No adjustment in use by operator like 53-54.

As to working on it, the evaporator takes a huge amount of space under dash--the glove box has to be shortened to fit because of the depth--and is odd shaped but almost full width-maybe a foot clear on left side. Air flow is different because heater/defroster also feeds into and out of that box. Needless to say, any other work under there can be a challenge. Under the hood, things relocate but probably the biggest one is the blower mounting makes working on anything back on drivers side a pain. The thread on fuel injection has a pdf file containing photos of that Exec with factory air so you can get an idea. Forget about checking brake fluid from the top.

Failure wise, I have two Lehigh compressors --one with shot valves and other with unknown issue. Valves are the typical round diecut flat metal "reed" or "flapper" type but from what I can find, NLA. When one failed, it broke apart and flooded the system with tiny fragments which also messed up the modulator valve.

As an aside, In my case have decided there are not many options to repair the Packard parts--unless someone knows someone who can make 2 sizes of valves without having to set up for a run of 10,000 each. Because of the 4 pistons in this unit, these are smaller than comparable 2 piston York and other compressors I could find valves for. A machinist friend attempted and did a commendable job with shape but didn't have a rotary table at the time so circle was crude and wouldn't work. I think I have the tools now but not the skills and he isn't around so still not a good match-although am tempted to try. Or could just make all the mods to put on the reliable Sanden with cycling clutch and have done with it.