R-12 to R-134a conversion made simple.

[aston_jag_tech]

Heres how I converted my 89 a/c system from r-12 to r-134a.

Evacuated R-12 and oil.
Added adapter fittings to R-12 lines.
Pulled system into a deep vacuum.
Added oil and r-134a to system(4.24lbs)
Ate a piece of pie while charging....
Blows cold baby!

I work in a shop so this costed merely $20.

Works F'ing Fine!

[whiskychaser]

Heres how I converted my 89 a/c system from r-12 to r-134a.

Evacuated R-12 and oil.
Added adapter fittings to R-12 lines.
Pulled system into a deep vacuum.
Added oil and r-134a to system(4.24lbs)
Ate a piece of pie while charging....
Blows cold baby!

I work in a shop so this costed merely $20.

Works F'ing Fine!

Er... arent you supposed to at least change the receiver/dryer and pressure switch? Not to mention all the seals and the hoses. Mind you, at that price you can top it up every week

[shogun]

I did the same 2 years ago with one of these 30-50 $ R12>R134a conversion kits, but also replaced the dryer and the pressure switch. Till now works fine, blows cold, never had to add / charge since then.

[Tiger]

He's a mechanic... Reason for receiver dryer is to capture excess oil and any moisture in the system... but since you vacuum the system for 30 minutes... hardly if any moisture because it boils off under vacuum... so this part is practically 'optional' but is a good practice to change it.

As for the pressure sensor... yes, if there is one for the R134... lower pressure... is better but again... not really needed.

[Rus]

From what I've read before, the reason for changing the dryer lies with the fact that R-12 and R-134 use different desiccants and to avoid introducing any contaminants from the old dryer into the newly recharged system. Hope it works out well for you

[shogun]

Pressure switch I had to change, because I still had the old one with 3 connectors.
Cars before 2/89 have three pressure switches mounted on the dryer. A high pressure switch, a low pressure switch and an intermittant pressure switch. The updated design only has 1 switch that is used for low and high pressure detection. The intermitant pressure switch will no longer be used.
http://bmwe32.masscom.net/johan/airc...con_R134a.html

[aston_jag_tech]

Right on guys!

Yeah Ill update this thread if I have any issues. Due to my a/c system not having a microfilter I spent a good half hour cleaning all the build up of dirt on the evap.. ewwww

[632 Regal]

409A works as a conversion also, just gets so cold that the evaporator will freeze, solution is to slightly overcharge. Won't post my EPS cert # tho ;-]

[Scott C]

409A works as a conversion also, just gets so cold that the evaporator will freeze, solution is to slightly overcharge. Won't post my EPS cert # tho ;-]

Easy enough to get cert - i did it online for some time and about $50

[Rus]

Right on guys!

Yeah Ill update this thread if I have any issues. Due to my a/c system not having a microfilter I spent a good half hour cleaning all the build up of dirt on the evap.. ewwww

How did you access the evaporator? I'm thinking of doing this on my car and am wondering if access is the same as the filter-equipped cars.