R-12 vs R-134a Hose

kejob · 04-03-2009, 06:42 AM

I need to replace the A/C hose on my 84 E30 318i that goes from the compressor to the evaporator. The system has been previously converted to R-134a. There are two hoses listed, R-12 64-53-1-377-821 for $72.50, and R-134a 64-53-8-391-051 fro $262.50.
Can I use the one for the R-12? The only difference I can imagine would be the recharge connection. Can I just use an adapter and save $200?
Then again, there are two different expansion valves. They are the same price but I was wondering what the difference would be. Maybe the size of the internal orifices?
Please let me know what I need to look for when replacing A/C parts. Once I do I will need to have an A/C tech to check everything and charge the system.

metalvolks · 11-14-2009, 09:03 AM

I have the exact same question regarding the 2 different hoses... anybody out there know?

Paul

kejob · 11-14-2009, 02:30 PM

Hey, the only difference I could find between the two hoses was the connection on the low side. To use R134a with the R12 hose, it requires an aluminum adapter which is a part of the conversion kit available from Pelican.
I just replaced all the rubber hoses, O-rings, R134a expansion valve, drier, and compressor (rebuilt-$50 on ebay) and it blows colder than it ever has. The compressor has a bad vibration at idle and I just turn the compressor off while at stops. But I found another one on ebay again that I haven't swapped out yet. The weather has been starting to cool a bit here in Florida so I haven't been using the A/C as much.

metalvolks · 11-14-2009, 03:03 PM

Yeah, i understand the difference between the R12 and R134 fittings, however, what is the difference between

http://mpowerparts.com/UserFiles/Image/originals/ACHOSEEvaptoComp.jpg

and

http://mpowerparts.com/UserFiles/Image/originals/64_53_1_384_485.jpg

Part numbers #64538391051 (R134) and #64531377821 (R12) respecively.
The first one is the R134 hose - $205 and the second a R12 hose - $55. Since R134 runs at slightly higher pressures, i was thinking that the hose is a little more reinforced than the R12 hose, but it looks very similar. Anyway, thanks for the message.

EDIT: I just reread your last post. So, your saying that I buy an new R12 hose and buy the conversion kit to make it a R134 hose? Just so I get this straight, the conversion kit is NOT the little adapters you put on the high and low side ports, correct? It sounds like its a fitting you splice onto the new hose (or just an adapter) that screws onto the compressor?

Paul

Paul

kejob · 11-14-2009, 04:47 PM

Paul,
The only difference I could determine was the low side connector. The rubber part of the hose may handle higher pressure but I don't know for sure. Being the low side of the system, I don't think it will make much of a difference. But, I had my car originally converted about 7-8 years ago with a new Sandin compressor (at that time), it worked fine up until this summer. I tried to recharge it myself and it lasted a day. So I decided to overhaul the whole system.
If you check out Pelican's R134a Retrofit Kit #55-9807-901-M325, you will see a bunch of O-rings, a conversion label, a red & blue plastic cap, and then those aluminum adapters. Those adapters screw over the R12 fittings (NO splicing!) on the R12 hoses. The hoses bolt directly to the compressor and the other end to the expansion vale next to the evaporator (inside your car under the dash). You only need to use the new O-rings. That's what I did. It saved me 200 bucks!