Petza914

Looking for some help and/or advice here. I have my '79 5-speed at a shop sorting out some general wiring issues as well as the A/C and HVAC. They've told me that my car has the original Bosch Compressor and has never been converted from R12 to R134A. They can put 134 into the system, but say it's their experience that the Bosch compressor won't last long with that. The solution would be to change to a Nippondenso Compressor, which means the lines and brackets also need to be changed. The question is should I do this and if so, are these parts available used or should I try to find some R12, recharge the system as is and hope for the best?

Feel freet to comment on anything related as well. Thanks.

ROG100

R12 all the way. Readily available - I sell it by the can if needed. System was designed for R12 so stick with R12.

Petza914

Thanks Roger. They're going to test the system to see if it has any R12 currently in it. If so, that means that the system is sound and I'd need to purchase some R12 from you and that they'll just recharge the system. If the system is empty, then there's probably a leak somewhere and if so, might be worthwhile to make the change to R134a. Would you agree? What the cost on your cans or R12? Thanks.

Rob Edwards

Testing the system = 0.1 second of depressing the pin in the high-side valve to see if there's any residual freon in the system. If so, great, you don't have any gross leaks. But you still (at the very least) need to have them pull vacuum on the system and let it sit for a couple of hours to make sure it'll hold vacuum, then recharge with R12. Better still would be to drop the compressor and drain all the oil out of it, replace with the proper volume of oil, replace the receiver-drier (a $75 part, 928 573 941 03), pull a good vacuum on the system and recharge with R12. Better than that would be all of the above plus a flush to get all the oil out and change all the o-rings in the system. All a matter of where you want to be on the cost-performance-reliability spectrum.

If there's nothing in the system, then obviously there's a significant leak that needs to be identified and repaired, otherwise recharging is a waste of freon. But I would still stick with R-12. 30 lbs can still be had for $15 a pound locally here in the PRK if you're willing to have a big jug of it on the shelf. IIRC, Roger's got it for $35 a can (?)

docmirror

I'm going with R-12, and prolly drain off the oil and repl the dryer. Not sure if I can find leaks well enough, but with Sean helping, we should be able to get it sealed. I want mega-AC on this car, and I will have it. Also wondering about some kind of fake rear glass louvers. Yes, I know they are butt-ugly, so get bent.

hb253

Contact griffiths.com for a different opinion. I plan on using them to convert system to R-134a

Hugo

The Forgotten On

^^I used the griffiths kit in my 81. It works wonderfully and gets super cold with r134.

It is well worth it just to preserve the original components and update to something more efficient and cheaper to replace if something ever does go wrong.

ROG100

78 & 79 system is totally different to 80+
Original Bosch compressor works well but needs R12. R12 is $35 a can.
Do change the dryer as Rob suggests - my price is $42.

My issue with Griffith is that they think the 78 & 79 cars were fitted with the Denso compressor like the 80 to 89 cars. You would think they would do their home work before offering a replacement. At circa $800 there kit is not cheap. Much cheaper to work with what you have. If that fails then look at upgrading to the 80+ system but stick with R12.

tmpusfugit

In addition to most likely needing all the O rings replaced along with the dryer, the hoses will be highly suspect by this time. 2 of the hoses are easy enough to replace or have them repaired with modern barrier house. The 3rd hose is connected to a brass tube that runs around the engine and up to the expansion valve at the windshield. It is not easily removed for hose replacement. I did everything including a new compressor, O rings, dryer, expansion valve, new hoses (easy 2) but did not change out the 3rd hose.Vacuumed down the system, added the correct amount of R-12. About $1000 spent, did all the work myself. Worked absolutely great for about an hour. Big psssst! Yes, the 3rd hose blew.......R-12 is not cheap....

waynestrutt

Feel freet to comment on anything related as well. Thanks.[/QUOTE]

Pete
Read these.
http://www.allpar.com/eek/ac.html

http://www.performancetrucks.net/for...future-486239/

Good info re hoses and orings as well.
134a is highly flammable and toxic when burning, and is being phased out. It will be very expensive in the future.

Good info for all here

SeanR

While some of what you say is true, as in R-134a is going to get expensive, it's not because of being flammable. We can blame the ******** at the EPA for that along with the demise of R-12. The expense is going to be converting to whatever clusterfvck that is going to replace 134a as that stuff is slated to be 4x the price.

If you can keep R-12 in your system, do so as it is what the system was designed to use. But do so only knowing that your A/C is repaired, tight and not going to leak (or have a nice supply of R-12 on hand). A properly running 928 system is going to last a very long time with a single charge of R-12 but getting there the correct way is not easy or cheap. All seals and hoses should be replaced along with the drier and expansion valve/s.

Most shops will pull apart an A/C system, replace whatever seals they see fit, vacuum it down and fill you up with R-134 and say they converted you. That's not what should happen. If you want to change to R-134a, all the above will be needed along with a good flush of the system so the mineral oil is removed from the system. I've had some pretty good luck converting to 134 but it was not cheap. Most of the ones wanting to convert want the cheaper fill ups if it leaks down. Do it right the first time so you don't have to keep getting an A/C service done.

The Forgotten On

You can actually thank Mercedes for having r134 phased out. They are the ones doing the r&d on the new refrigerant.

So far though it has been flammable and unsafe in crash tests that I know of; so it is unknown when it will be the new refrigerant of choice for OEM's.

SeanR

I can open up a can of R-134a right now, put my blow torch to it and it won't flame up. That's the fun of common sense, once that's out the window anyone can make a claim.

Rob Edwards

R12 is $15 a pound on Ebay. r134a is $3.50 a pound on Ebay, with free air fresheners thrown in for good measure.

http://www.ebay.com/itm/DUPONT-SUVA-...450a7a&vxp=mtr

Why is there so much hand wringing about availability? Do people think the EPA's going to start door to door search and seizure missions? Just buy a 30 lb jug or two, hide it under the mattress, and enjoy the lifetime supply.

Petza914

My system passed the vacuum test so I've ordered some R12 for my shop and we're going to recharge with that and see where we are. I've also pointed them to this thread so we can evaluate replacing the other items referenced in the earlier posts like o-rings, compressor oil, etc.

Thanks for all the input guys.