DIY 134 conversion in SC complete!

[jimz61]

Tim,

Did you install an "L" shaped fitting on the low pressure side of the compressor? It seems necessary in order to access the fitting to fill the system. If so, where do I find one?

-Jim

[Tim Hancock]

On my York, the service valves are mounted via swivel type joints to the compressor. I was able to pivot the lower service valve upward enough (rotate it clockwise) to install the low pressure hose from my borrowed AC gages. If you have a York with the service/stem valves, your's should pivot also.

I think it swivels enough to install the low side 134 adapter and charge hose from the cheapo 134 conversion kits, if you do not have gages w/ the sae fittings.

[Tim Hancock]

Having just read a current thread about whether or not to repair AC in these cars, I thought I would post an update on the controversial method I used at the beginning of last summer.

There are a few AC pros on this BB that know their stuff and I agree in theory with most of what they advise when it comes to AC, however I just want to let everyone know that suprisingly, my AC is still working as of last week. I have not put gages on it, but it still blows cold after 1 whole hot humid summer and a long winters nap in storage. I actually figured I would need to add a bit of 134 this spring, but last week I used it on a warm day and it still blows cold!

It still is proving to be the best $25.00 I have spent on this car YMMV!


PS my 260,000 mile, 134 converted BMW AC mentioned earlier is still working good with no recharge in over 3 years. Maybe I should start buying lottery tickets.

[1982911SCTarga]

Tim, I'm just beginning to sort my AC and on my York, the suction side has a Schrader valve. The high pressure (discharge) side does not have a Schrader valve. By the way, the system is currently plumbed for for R-12.

I don't quite understand how the system holds pressure on the high side with a plastic cap alone on the test port, or does the backseat valve get screwed in part way or something? If you go all the way in with the backseat valve, aren't you closing off the whole discharge side?

Also, on my York both the discharge and suction valves have 7/8" male fittings.

I've dealt with other AC systems (replaced the evaporator on my wife's Cherokee -- just a simple weekend project). The 911/York system is a little confusing (Schrader/no Schrader, etc.)

Brian

[tsuter]

Originally posted by Tim Hancock
It still is proving to be the best $25.00 I have spent on this car YMMV!

Of course. The masses of "keyboard" mechanics on this forum over engineer everything.........

[Tim Hancock]

Originally posted by 1982911SCTarga
Tim, I'm just beginning to sort my AC and on my York, the suction side has a Schrader valve. The high pressure (discharge) side does not have a Schrader valve. By the way, the system is currently plumbed for for R-12.

I don't quite understand how the system holds pressure on the high side with a plastic cap alone on the test port, or does the backseat valve get screwed in part way or something? If you go all the way in with the backseat valve, aren't you closing off the whole discharge side?

Also, on my York both the discharge and suction valves have 7/8" male fittings.

I've dealt with other AC systems (replaced the evaporator on my wife's Cherokee -- just a simple weekend project). The 911/York system is a little confusing (Schrader/no Schrader, etc.)

Brian

Brian, I do not have one in front of me right now, but the service valve when the system is in operation mode, isolates the service port (the plastic cap is just to keep dirt out of the service port when not in use). To add refrigerant or monitor pressure with gages, you have to open the service valve so that the now connected service ports are exposed to the system. These service valves typically have a metal protective cap on them that needs to be unscrewed to expose the 1/4" square valve operator stem. I don't remember which way to turn, but I think I detailed the procedure on the first page of this thread.

On the older SC's at least, all the hose connections thru-out the system happen to be 45 deg SAE flare connections (no o-ring connections). Newer cars went to o-rings I think. The ability to go to a local auto parts store for fittings, is what allowed me to easily fab up a tube to allow the generic drier to work out for me.

[Porsche_monkey]

More info here...

http://forums.pelicanparts.com/showthread.php?threadid=165899

[Tim Hancock]

DIY AC update:

After two years of use and after taking the '79 SC out of winter storage and using the AC a couple days ago, it will finally need a top off of 134 as it is blowing cool, but not cold.

Two years before needing a charge on an old York and old lines running 134!

To all the naysayers:

PS: my BMW I mentioned previously in this post finally required 1/2 a can of 134 at the end of last summer (about four seasons of use before needing recharged)

[psychII]

Thanks for the write-up and update!

I am getting ready to undertake this project on my 928. I would like for this to be a total DIY, but I can't find a place to rent or loan a vacuum pump.

I am planning to dump the oil in the compressor and replace with new, along with new o-rings. With my luck, the system will explode if I don't.

[psychII]

ha

I found this link through another thread and just noticed the date...

hope it has not exploded since 3/07

[Tim Hancock]

Originally Posted by psychII

ha

I found this link through another thread and just noticed the date...

hope it has not exploded since 3/07

No explosions and it still worked great this summer although I did have to add one can of 134 in June.

[G50]

Originally Posted by Tim Hancock

Next I borrowed a vacuum pump and evacuated the sytem for several hours.

Tim (or anyone else!),

What exactly does the above mean, how do you do it, specifically?

Thanks!

[chamilun]

you attach a vacuum to they system which 'burns' off any contaminents/moisture in the system. you can rent one from autozone, or buy one for a bit of $$$.

this is needed anytime you open the system

[jefferyGT]

Originally Posted by Tim Hancock

Update on above described DIY 134 conversion/repair with 26 yr old stock York compressor:

It has been 4 wks since I did this and all is well (no black death or whatever it is called). My vent temps while moving down the road on 95 degree days is holding at 45 degrees. I have driven 80 miles round trip nearly every day with 85-95 degree temps (why is it so f'ing hot in Ohio in June?!?) The first few miles on the way home are stop and go and it IS warm in the car until I get to the highway at which point the car cools down quickly and after about ten miles, I have to back down on the AC controls.

Just thought I would give a real world update for anyone else contemplating doing the same.

Thank Al Gore for th ehot Ohio weather. And the internet. And thus the Pelican forum.

[Tim Hancock]

Just checking in with my yearly update on my SC's AC condition. Had to put two cans of 134 when it started getting hot this summer and I tried to use the AC.... Not 100% sure, but I believe slightly loose hose clamps on my DIY low pressure hose splice is to blame. Tightened them up and all is well with my old York AC system.

FWIW.... '92 325i BMW that I put 134 in many years ago is still blowing cold at 308,000 miles on the original AC system and hoses.

[Willemwild]

Sorry, dont want to highjack the thread, but though it may be relevant to the topic and useful to others.

I dont know the history of my recently purchased 911SC (81). Is there any easy way to check if it is still R12 or already converted to 134?

[Tim Hancock]

After sitting in storage the last 5 years I decided to dig my old '79 911 out of mothballs and get it going again.

On a whim I decided to try to get the AC going again too. (I originally posted this thread 19 years ago. )

Vacuumed for an hour then recharged with about 3.5 cans of 134 and low and behold it is blowing nice and cold again. Will have see how it does for the rest of summer. Thought some here might appreciate the LONG term update.