A/C Rebuild 69 Chrysler 300

[MJFUR]

I have a 69 Chrysler 300 with a functioning A/C system that was converted to R134 20 years ago, everything is OEM and most likely original to 1969.
The problem is that there is a small leak somewhere. The first time I serviced it it lasted about two years. Now it lasts about a year. It will hold a vacuum but leaks with pressure. Using an ultra violet light you can see minuscule traces of glowing green in various places but nothing obvious or fresh. Various bug guts and sealants glow green as well.

I was going to start my way from the Condenser back to the Evaporator. What are my options for parts if needed? Are there any new build items or am I stuck looking for old NOS items?

Has anyone used a R134 sniff tester? Will they work with such a small leak?

TIA,
Mike

 

[Davea Lux]

Do you know if the o-rings at the connections were replaced with the high density green ones when the conversion was done? R-134a is a smaller gas molecule that is more prone to leaking. The leak sniffers work well for moderate leaks as long as the air is still. Check the connections for leaks, a leak at a connection will usually leave some oil residue at the point of the leak. The RV2 compressor will also sometimes leak at the input shaft in which case a new seal will need to be installed. If it is taking a year or more to need recharging, you have a small leak that you will probably not find with a sniffer. Green o-rings are a universal fit item and are readily available. Front shaft seals for the compressor are also still readily available. A hose with a microscopic leak will have to be fabricated as new replacements are no long available.
Dave

 

[MJFUR]

Do you know if the o-rings at the connections were replaced with the high density green ones when the conversion was done? R-134a is a smaller gas molecule that is more prone to leaking. The leak sniffers work well for moderate leaks as long as the air is still. Check the connections for leaks, a leak at a connection will usually leave some oil residue at the point of the leak. The RV2 compressor will also sometimes leak at the input shaft in which case a new seal will need to be installed. If it is taking a year or more to need recharging, you have a small leak that you will probably not find with a sniffer. Green o-rings are a universal fit item and are readily available. Front shaft seals for the compressor are also still readily available. A hose with a microscopic leak will have to be fabricated as new replacements are no long available.
Dave

I do not know. It was done before I owned the car. Thx

 

[CBODY67]

In one respect, your "leak" is not unusual. When our '66 Newport was newer, it would normally take a little bit of R12 every year to top and get ready for the upcoming summer season. Back then, that was considered normal. So, in that respect, nothing out of the ordinary.

I concur on the green o-rings. After a full evac, that can be the first thing to change. Might plan on changing the receiver/drier too, for good measure (they don't last forever, unfortunately).

You can pay special attention to the ends/flanges of the condenser as sometimes the solder there can not seal as well as it used to, with age.

An "oil trail" on the inside of the compressor clutch pulley can point to the need for a new front seal, but do this last, for obvious reasons.

Just some thoughts,
CBODY67

 

[MJFUR]

For some reason both of my 69 Parts Manuals only show Valiant, Dart & Barracuda parts info for under the hood items.

Without having it apart are there green o-rings for every hose connection or are some metal to metal flairs?

Receiver/Drier - NOS or something new available?

Thx

 

[Davea Lux]

For some reason both of my 69 Parts Manuals only show Valiant, Dart & Barracuda parts info for under the hood items.

Without having it apart are there green o-rings for every hose connection or are some metal to metal flairs?

Receiver/Drier - NOS or something new available?

Thx

Most of the connections will have o-rings, some expansion valves are a metal flair where it hooks to the evaporator.

Dave

 

[CBODY67]

The OEM receiver/driers were usually long, about a foot or more, as the replacements (even in the 1990s) were about half that length. As were some of the earlier ones.

I would err toward the NEW ones, rather than not. I would suspect that even with plastic plugs and being in a cardboard box, internal moisture can result just from ambient air temperature swings on the warehouse shelf.

NOS is not worth the money, unless you are going into a Concours Judging event somewhere. In which case the orig part might be rebuilt and repainted "as new" looking.

Just some thoughts,
CBODY67