1969 cadillacs

[1969cadillac]

hello!

I own 2 cads , both 69s

one is a deville hardtop with 50k miles

and the 2nd a limo with 75 k miles

most of the A/C system is original and I would like to start replacing components in terms of reliability

the TX or expansion valves look original , is it worth replacing them ?, since I am replacing hoses and compressors ?

is the 4 seasons brand ok ??

Murray Mules

[The Tassie Devil(le)]

Are you going to be running R134a, or R12, or an equivalent?

Are the systems still operating?   Or have they been left open to the atmosphere?

Bruce.

[Scot Minesinger]

If systems function OK, would not mess with them until they require attention, as otherwise you can create unnecessary trouble/expense.  I am all about precautionary work to classic cars to insure reliability which leads to more fun driving.

If systems do not function, then if that is recent or they have not for a while:

Decide to use R134 or R12.  I recommend R134, and others disagree.  R12 cools better, but R134 is readily available and allows serving by just about any automotive repair shop.  If there was an issue with your system R12 system that is not a leak (such as bad POA, bad exp valve, bad compressor, or bad drier for example), then the R12 has to be removed, and few are equipped to do this.  Most are equipped to repair a leaking R12 empty system and charge it.  In any event:

1.  Replace all three refrigeration hoses, probably best if you re-use the ends and get new hoses, but you can buy hose sets with new ends on them, but they are always just a little different and not clocked correctly.

2.  Replace all "O" rings.

3.  Replace drier at front of condenser on passenger side.

4.  Remove expansion valve and POA and soak in A/C Pro or other good refrigerant oil solvent, then reinstall.

5.  replace all vacuum hoses on controls side under hood and all hoes that penetrate fire wall.

6.  Remove blower and look inside casing to be sure it is vermin free (snake cameras).

7.  Check to be sure drain hose that keeps vermin out is installed underneath evap casing.

When recharging be sure and add oil to systems that were replaced or cleaned.  use mineral oil for R12, and synthetic for R134, do not use the universal type especially if going to r12, it draws in moisture.

If system was working before recently and stopped it is likely either from a leak, failed compressor, or failed climate control components. 

If system has not worked for a while, I would dismantle heating and cooling fiberglass and plastic casings on firewall and clean them up. 

Compressor could be good, the one on my 1970 is original no matter what.  You will have to put a set of gauges on it and make sure it does not leak to be sure.  I think the green die is best, because it is great for finding bad compressor seal.

BTW if you do not have shop manual and Cadillac Tim's (Google, he is in Iva, SC) climate control book, would definitely get them.

Good luck, and enjoy your 1969 Cadillacs!