girraffe

What "oil" are you guys talking about? Do you add oil into the lines before you charge the system? Not sure I'm grasping that part of the discussion...

worshipmentor

iTrader: (3)

Ester or PAG oils will both work with R-134a. You should add oil to the dryer when you replace it (ALWAYS recommended when converting R-12 systems to R-134a)

modlite

I bought the retrofit kit from Walmart. The port on the compressor, I found a fitting to fit on, but it is pretty long and I'm not sure I'm going to be able to hook up the manifold guages to it because it sticks out so far, and will run into the motor block trying to hook em up. Anyone else have this problem?

The MAN

try getting another adapter fitting... there are 90 degree ones available to overcome clearance problems

The MAN

not merely just recommended, but required as most of the oil needs to be replaced with esters or PAG (not completely, but mostly)... most of all though, R12 systems for the most part have incompatible desiccants in the driers/accumulators... an XH7 or XH9 type drier must be used, which is compatible with either refrigerant and is currently the only kinds of driers available in the market

YOAKUM_AZ

i read that the condensor needs to be replaced and accumulator can be flushed,. Is that true or is it the other way around?

worshipmentor

iTrader: (3)

YOAKUM it's the other way around. The accumulator (or receiver-dryer) should be replaced because
1) It is the largest reservoir of oil in the system and R-134a uses a different oil than R-12.
2) The fact that if it is old enough to have had R-12 in it the desiccant needs replacing anyway.
There will probably be people that tell you this is all unnecessary but having worked on auto/heavy truck/equipment A/C since the early 90's I have a bit of knowledge. Changing these components may not make your system work better in the short term but it will provide better service life for your expensive parts/chemicals. Make sure the system is well sealed (best way is a micrometer) and pull a vacuum............ when you think it's done shut the valves and watch the gauges for a while.......you are NOT pulling a vacuum to get the air out: you are pulling it to remove moisture! (water boils at room temperature in a vacuum and can be sucked out as a vapor). Moisture is your biggest adversary in A/C system life expectancy. I have seen extreme cases where it freezes in a line and stops up the metering device.
OH, do yourself a favor and check your evaporator coil as well. If you run your system on fresh air (I NEVER RECOMMEND THIS) it draws in external air/dust/dirt/leaves etc. so check that it is clean and shinny. It might require removing it to thoroughly clean it but it beats tearing your system back apart after you have it working (or dealing with an inefficient system).
Hope this helps, let me know if you any more questions!

Chris

worshipmentor

iTrader: (3)

When was the last time you saw a drier that wasn't compatible with R-134a? I've been doing this for 20+ years and haven't seen any in probably half that time.

YOAKUM_AZ

Thanks chris,

I actually have one more question. How do you know how much r134a you need in the converted system, compared to how much r12 there was when it was stock?
I'm gonna vaccum the a/c system on the 10/8 to make sure there is no moisture, and that i fix the leak issue which got me to decide to convert it. Before i add the r134a.

Thanks agian.

worshipmentor

iTrader: (3)

Yoakum, that's an interesting question. I have seen conversion charts for it but haven't had much success using them.
Back in the R-12 days you charged until the bubbles went away in the drier sight glass. I have found though that doing so with R-134a overcharges them. You really have to charge by temperature/pressure/feel. One big issue I fought with mine (granted I live in Mississippi) was the radiator fan. I had a new clutch, clear air flow and a good shroud but I still couldn't get slow/stopped traffic cooling that I wanted. You see, one of the issues with R-134a compared to R-12 is R-134a runs a higher head pressure. The solution for me was to convert to an electric fan (a fairly simple swap with a mid 90's Mercury Villager minivan unit. There are threads on the forum about it).
Long story short, I like to see 15-20 on the suction side and 225-275 on the discharge under simulated driving conditions (cruising RPM and if possible a shop fan blowing across the condenser). Idle pressure should show about 35-40 suction and 175-225 discharge.
Hope this helps man. If you were local I'd be happy to help you but Az is a bit of a drive ! Lol

Chuckar

Don't know what your working on but maybe this will help.

http://www.ccar-greenlink.org/tms/Ne...r/ac002t98.pdf

YOAKUM_AZ

Thanks for the help you guys, both of you helped a bit. Hopefully by this sunday i'll have a/c again, but this time no leaks. Appreciate the help.