1960 Caddy Hot Gas Bypass valve rebuild

Friendly format provided to inquire about automotive a/c systems.
Archived Forum

Moderators: bohica2xo, Tim, Dougflas, HECAT

Big Dave
Posts: 3
Joined: Mon Dec 17, 2018 7:15 am

1960 Caddy Hot Gas Bypass valve rebuild

Postby Big Dave » Mon Dec 17, 2018 7:53 am

B4BD4A9E-01A5-4632-BE68-AD5169A65D5D.jpeg
B4BD4A9E-01A5-4632-BE68-AD5169A65D5D.jpeg (24.1 KiB) Viewed 3989 times
Hi All,
Found this forum out of my search for AC info on a 1960 Cadillac rebuild. The car has the original AC system, and has sat idle for 45 years, but still had pressure on the system! Generally, it’s fairly straight forward to get this going again except for the hot gas bypass valve. I’m in the process of rebuilding it with a new rebuild kit, but not sure how far it comes down. The valve action is pretty simple, but there are three small standpipes on the main body which don’t budge. I’m not sure if they actually come out. Each on has threaded connections at the end for hoses, but the pipes themselves may be pressed into the body, or threaded, I can’t tell. Has anyone rebuild one of these units? They are similar to a ‘59 and a ‘61, but this one has the small pipes in question. Thanks for any advice, Dave
User avatar
bohica2xo
Posts: 597
Joined: Wed May 11, 2016 4:12 pm
Location: Las Vegas, NV

Re: 1960 Caddy Hot Gas Bypass valve rebuild

Postby bohica2xo » Mon Dec 17, 2018 9:27 am

Those are brazed in to the body. Don't try to remove them.

Check the cam surface, and pintle for wear. Check the cam pivot too. Lubricate the pivot with a tiny bit of good oil, and the cam surface with a thin film of wheel bearing grease.
Big Dave
Posts: 3
Joined: Mon Dec 17, 2018 7:15 am

Re: 1960 Caddy Hot Gas Bypass valve rebuild

Postby Big Dave » Mon Dec 17, 2018 9:54 am

Thanks bohica2xo!
Wow, I didn’t give brazing a consideration. That makes it easy then. I really appreciate the help!
Dave
User avatar
bohica2xo
Posts: 597
Joined: Wed May 11, 2016 4:12 pm
Location: Las Vegas, NV

Re: 1960 Caddy Hot Gas Bypass valve rebuild

Postby bohica2xo » Mon Dec 17, 2018 9:57 am

Many of them had straight fittings like this one:

https://www.autoacforum.com/messageview.cfm?catid=2&threadid=31064

But I think they went to the brazed pipes to get away from the 135 degree hose fitting. Pipes are more robust and cheaper.
Big Dave
Posts: 3
Joined: Mon Dec 17, 2018 7:15 am

Re: 1960 Caddy Hot Gas Bypass valve rebuild

Postby Big Dave » Mon Dec 17, 2018 10:46 am

That makes sense, those are some tight bends in aluminum tubing. This system will continue to use R-12, with 525 oil. Even though the books show the A6 compressor started later, this ‘60 has a ver old style A6 already installed. Due to the low miles and the fact that it hasn’t seen the road Sind 1973, I have to wonder if this car was fitted a few years later with AC. But who knows what could have happened 55+ years ago.
Dave

Return to “Automotive Air Conditioning Forum”