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1960 Caddy Hot Gas Bypass valve rebuild

Posted: Mon Dec 17, 2018 7:53 am
by Big Dave
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B4BD4A9E-01A5-4632-BE68-AD5169A65D5D.jpeg (24.1 KiB) Viewed 4180 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

Re: 1960 Caddy Hot Gas Bypass valve rebuild

Posted: Mon Dec 17, 2018 9:27 am
by bohica2xo
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.

Re: 1960 Caddy Hot Gas Bypass valve rebuild

Posted: Mon Dec 17, 2018 9:54 am
by Big Dave
Thanks bohica2xo!
Wow, I didn’t give brazing a consideration. That makes it easy then. I really appreciate the help!
Dave

Re: 1960 Caddy Hot Gas Bypass valve rebuild

Posted: Mon Dec 17, 2018 9:57 am
by bohica2xo
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.

Re: 1960 Caddy Hot Gas Bypass valve rebuild

Posted: Mon Dec 17, 2018 10:46 am
by Big Dave
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