Advice, please, how to convert back to R-12 - PeachParts Mercedes-Benz Forum

FRANKNBENZ · #1 08-27-2007, 04:26 PM

Noble Forum Fellows,

I hope I have searched all the forum threads on this subject but may have missed, or are too dense to understand, how to re-retrofit #2 Car, a W123 85 300D Turbo, back from R-134a (done by PO) to R-12. Please, some points and questions:

1. The hoses appear to be in good condition. They are either the originals, or they are R-134a "barrier" hoses; light blue, no markings. Q: Can these remain when going back to the chunkier molecules of R-12?
2. After recovering the R-134a, I will do a system flush per Diesel Giant's DIY, except using a flush machine vice the aerosol route.
3. Per recommendations, I have on hand a new XValve and receiver/drier.
4. Per recommendations, I will need all new O-rings. Q: What type (neoprene, green) or is this important when going back to R-12?
5. Per EPA regs, I will install R-12 fittings and a label (if available). Q: Source for fittings, label, caps, can taps?
6. I'll be testing for the 609 certificate soon and am acquiring the necessary gagues and recovery gear. Q: Best source for R-12?
7. Car has a GM R-4 AC compressor, age unknown, but it clearly pushes R-134a now, if under higher pressures. Q: Replace? York? Nippondenso? Other? Source?
8. Q: Should I replace the air recirc pods (glove box?) as good PM?
9. Q: To increase system efficiency even with R-12, should the stock aux air fan be replaced with a larger diameter unit? Source?
10. Someone recommended Arizona Mobile Air (ackits.com) as a gear source. Q: Comments?

Please ID relative threads or answer directly. Thanks again.

deerefanatic · #2 08-27-2007, 09:31 PM

I recommend getting AC equipment and R-12 from Lenz Distributing.... http://www.lenzdist.com/

Great guys and great prices

I'd go ahead and put a New R-4 from Hodyon www.hancockindustries.com on, forget rebuilts........

Wouldn't hurt to put a parallel flow condenser on either... Would make for a killer system...

As long as the stock Fan works, I'd leave it.... Better going with the above mentioned Parallel flow unit as it is more efficient... Using electricity to push more air over an inefficient condenser is just a band-aid.... But I doubt you'll need to worry about either being in Maryland........

tangofox007 · #3 08-27-2007, 11:32 PM

Quote:

Originally Posted by FRANKNBENZ

Per EPA regs, I will install R-12 fittings and a label (if available). Q: Source for fittings, label, caps, can taps?

The original R-12 fittings should still be there, under the R-134 fittings. You can likely just remove the add-on R-134 fittings and be in good shape. But I would definitely install new valve cores.

TheDon · #4 08-28-2007, 12:05 AM

Quote:

Originally Posted by deerefanatic

I recommend getting AC equipment and R-12 from Lenz Distributing.... http://www.lenzdist.com/

Great guys and great prices

I'd go ahead and put a New R-4 from Hodyon www.hancockindustries.com on, forget rebuilts........

Wouldn't hurt to put a parallel flow condenser on either... Would make for a killer system...

As long as the stock Fan works, I'd leave it.... Better going with the above mentioned Parallel flow unit as it is more efficient... Using electricity to push more air over an inefficient condenser is just a band-aid.... But I doubt you'll need to worry about either being in Maryland........

how much is a new R-4?

FRANKNBENZ · #5 08-28-2007, 10:18 AM

Thanks, Deerefanatic,

Source for parallel flow condenser? Hodyon?
Any special fabrication required to mount the unit to the front of the radiator...or to the front chassis frame?

You're right! Lenz has a great selection and excellent pricing! Thanks

rrgrassi · #6 08-28-2007, 10:53 AM

Quote:

Originally Posted by TheDon

how much is a new R-4?

I got my Hodyon from NAPA in Wylie TX for $220.

Price will vary between retailers.

lonewolftek · #7 08-28-2007, 10:58 AM

For anyone else wondering what a "parallel flow condenser" does, there's a good writeup at:

http://www.forparts.com/techcondensers.htm

deerefanatic · #8 08-28-2007, 08:44 PM

Parallel Flow Condenser, ~$50 on ebay.... Universal fit, will need some mounting brackets made and some custom hoses......

Hodyon R-4 NEW ---- $175 direct from them.... 1 Year Warranty if installed by a 609 Certified tech with new Reciever, New Expansion valve, and system flush.....

♦

FRANKNBENZ · #9 08-29-2007, 04:15 PM

Thanks much, Matt. Since I will (soon) be the 609 cert guy (and have home schooled through both ASE manuals

), I guess I will be giving myself the warranty. I hope I'm satisfied with my work and am not forced to take it back to me

...I can be a real pain with poor workmainship.

deerefanatic · #10 08-30-2007, 07:05 AM

goto EPAtest.com.. They have the software you can download for free that has study materials and mock tests..... Great.... It's all I used to pass my 609 Cert with 100%.........