I have to fix my A/C compressor.
Please give thoughts on keeping R12 vs 134.
I am tired of thinking about it and need some
input.

 

Go woth the 134. This type of freon is so cheap versus R12 that if you have a leak or some issue it will be cheaper to fix if all of the freon leaks out.

Also make sure that your condensor is clean and not full of dust,dirt, leaves ,etc. last but not least is the evaporator core. Due to the crappy design, leaves and debris can get sucked in by the fan for your interior air distribution system. I have had many evaporator cores get blocked by leaves, pine needles and such. I remove the blower motor and it will allow me to connect a hose to my vacuum cleaner and reduce the hose size so I can get down in the area of the front face of the evap core and clean it out so better air flow can be obtained. This step is made easier if you have your heater core box out and can blow air through the evap core while vacuuming from the other side. You will be surprised often times what you will find. I start with an empty vacuum cleaner and then show the customer what was removed when completed.

Just trying to advise you on how to get the best air system you can.
Upgrading to a 1984 or 1985 blower moyot will give you more air flow, by 20%, but that is also requiring the air ducts are correctly sealed up so you do not loose air behind the dash due to these leaks.
"DUB"

 

Thanks Dub

 

Your system will be empty anyway, so I would split the evaporator box apart and take out the evap to flush it internally and clean it externally too. Then you can also clean out the box and replace the seals etc.
Use oven cleaner on the outside if you don't have the right cleaning acid.
You want to replace the orings anyway and going a little further isn't that hard.
Put a 10 ga ground wire on the blower and you'll gain a lot.

134 is a lot cheaper if you start having leaks in the future.

 

I am going nuts with deciding.
Now there is Freeze 12, 80% 134 plus something that carries
min oil.
Yet still eats seals like 134.

 

134 doesn't and mineral oil doesn't eat the seals, old wives tale,
freeze12 can be bad because they use propane or sometype of
gas in it. best bet go with 134, flush system, change 0-rings since
you are in the system just so they are new. you can buy r12 on ebay for about $15 a can vs the 8-12 for 134, your choice. good luck

 

Be carefull with the R12 subsitutes.
Convert to 134A and be done with it.

 

A couple of concerns.
the screen / orifice change out. is the screen itself the orifice valve?
white=R-12 green= 134 blue ford R-12 that works good for 134?

The pressure cycling switch, I did not see an adjusting screw for lowering cycle from 25 to 22.5? Is there a new one? PN ?

Ester oil mixes? not need to flush?

Will my condenser/evaporator stand the higher highside pressures of 134?

and apparently new shrader valves are required?

 

Most of the substitutes all have some flamables in it. BTW ALL refrigerants are flamable under pressure even 12 and 134 and with less than 3 lbs it's not that much of an issue.

Amost all new parts, accumulators, compressors, hoses, orings etc are compatable with all types of refrigerants. Only the oil is different, PAG for 134 and mineral for 12.
Products like Freeze12 don't tell you that after time the mixes separate and can cause problems and I don't know of any compressors that are waranteed with their use.

To make 134 work properly (as cold as 12), you must change to a parallel flow condenser and thus hoses too.
Some will make a big deal of the pressure differances, on the low side it's only 3.5 lbs and on the high side 30 lbs, no big deal.
Don't use ester, use PAG at the right viscosity for that compressor.
You can get all kinds of pressure switches and the adjustment is inside the port on most.
I personally have been using the variable OT, can't be any worse.

Add up all your costs either way and go with the cheapest. Your looking at approx 3 lbs of refrigerant.
When a 30lb can of 12 was 2000 bucks in the 90's, the choice was clear.
For the DIY'er 12 is the easiest and most forgiving.
Learning to do it all yourself is the first step. You don't have to understand the chemistry, just how to do it properly.