Air Conditioner R134a conversion

Topic: Air Conditioner R134a conversion (Read 3561 times) previous topic - next topic

Air Conditioner R134a conversion

July 27, 2021, 02:25:17 PM

So waaaay back in 2006 I had all the seals/o rings in my Thunderbird's AC system replaced and the system filled with R12. It lasted till this week. It leaked out, and being that the A/C components are original to the car I'm planning on swapping everything out to new parts and converting to R134a. I'll be grabbing a brand new compressor, all lines, and a new condenser from Rock Auto. I'm just looking for feedback on how well the system changed over to R134a works.

Re: Air Conditioner R134a conversion

Reply #1 – July 28, 2021, 09:20:45 AM

Wondering also. I "think" there is a better condenser to use for the 134 swap. Im listening as well.

Re: Air Conditioner R134a conversion

Reply #2 – July 30, 2021, 02:48:18 PM

Quote from: thunderjet302 – on July 27, 2021, 02:25:17 PM

So waaaay back in 2006 I had all the seals/o rings in my Thunderbird's AC system replaced and the system filled with R12. It lasted till this week. It leaked out, and being that the A/C components are original to the car I'm planning on swapping everything out to new parts and converting to R134a. I'll be grabbing a brand new compressor, all lines, and a new condenser from Rock Auto. I'm just looking for feedback on how well the system changed over to R134a works.

You're replacing everything but the evaporator, hard to go wrong there! Get a new compressor, not reman. Get a piccolo or parallel flow condenser, not tube/fin. Rockauto doesn't have any condensers in stock, so you'll need to use another supplier.
They make kits where you get a compressor, and a hose or two - which will save some money vs buying them piecemeal.

Blow out the evaporator with chlorinated (nonflammable) brake parts cleaner to remove the old oil.
Add in new PAG oil, pull a deep vacuum, and recharge with pure (don't get any with additives or leak-stop) R-134a. Boom, you're good to go.

Re: Air Conditioner R134a conversion

Reply #3 – August 10, 2021, 02:50:47 PM

Well I replaced everything but the evaporator with brand new parts from Rock Auto (Four Seasons). Evap was flushed but not replaced. With the system charged with R134a to 80% of the R12 value vent discharge temp was 36*at idle with and outside temp of 76* and 70% humidity. It's uncomfortably cold in the cabin with the A/C on max. The new condenser is the parallel flow type used on SN95 Mustangs but listed as the stock replacement for 88 Thunderbirds.

There were a couple of issues with the installation. First off the new compressor is slightly larger and has the rear mounting ears about 1/4" further back than the stock compressor. I had to slot the stock bracket that bolts to the rear of the compressor so I could attach the rear mount. Secondly the fittings on the lines are R12 fittings. Normally just using the R134a adaptor fittings would be fine. But in my case they wouldn't allow the Maximum Motorsports strut tower brace to be installed, as it would hit the R134a fittings. So the adaptors for R134a were installed to charge the system and removed afterwards to clear the strut tower brace. Thirdly the high pressure line is right up against the Performer RPM intake. That wouldn't be an issue with the stock intake. My suggestion, if you have and aftermarket intake or a strut tower brace, is to use the 87-93 Mustang high and low pressure lines for more clearance.

Re: Air Conditioner R134a conversion

Reply #4 – August 11, 2021, 02:59:51 PM

That's great information, thank you. I've been looking at updating all those parts myself once the car is fully on the road again. (The other night my wife asked "it has ac, right?" Er well the compressor is still there honey, just not hooked to anything) Is there anywhere that the mustang lines might foul on? I have a 351W based motor with a Victor Jr intake so I imagine there's more clearance than the EFI intake.

Re: Air Conditioner R134a conversion

Reply #5 – August 11, 2021, 03:33:08 PM

So as a FYI when you buy the A/C compressor kit from Rock Auto: https://www.rockauto.com/en/moreinfo.php?pk=5241963&cc=1140297&pt=17507&jsn=1249 it includes a FS6 sized compressor (Four Seasons part number 58111). The FS6 compressor is larger than the factory Denso 6P148A compressor, hence the fitment issues with the rear compressor bracket. The FS6 size compressor is slightly longer and wider than the 6P148A compressor. So if you want a new 6P148A compressor, to make it a bolt in process, the compressor is available, just not as part of a kit that includes the accumulator line and orifice tube. It's Rock Auto part number 7511750: https://www.rockauto.com/en/moreinfo.php?pk=3911826&cc=1140297&pt=6628&jsn=1257

That being said the compressor in the Four Seasons kit works fine, you'll just need to modify the stock rear bracket to make it work.

Re: Air Conditioner R134a conversion

Reply #6 – August 11, 2021, 05:13:00 PM

Oh nice, thank you. Great tip.

Re: Air Conditioner R134a conversion

Reply #7 – August 13, 2021, 10:10:47 AM

Quote from: thunderjet302 – on August 10, 2021, 02:50:47 PM

The new condenser is the parallel flow type used on SN95 Mustangs but listed as the stock replacement for 88 Thunderbirds.

Any info on the condenser? Get it at RA as well? Part number. Thanks.

Re: Air Conditioner R134a conversion

Reply #8 – August 13, 2021, 10:50:28 AM

Quote from: mcb82gt – on August 13, 2021, 10:10:47 AM

Quote from: thunderjet302 – on August 10, 2021, 02:50:47 PM
The new condenser is the parallel flow type used on SN95 Mustangs but listed as the stock replacement for 88 Thunderbirds.

Any info on the condenser? Get it at RA as well? Part number. Thanks.

It's this one, part number 3554: https://www.rockauto.com/en/moreinfo.php?pk=6377508&cc=1140297&pt=6708&jsn=910

Re: Air Conditioner R134a conversion

Reply #9 – August 20, 2021, 03:14:39 PM

So.......where the heck is the orifice tube on these '88's?? 5.0 XR7.......??? Thanks!

Re: Air Conditioner R134a conversion

Reply #10 – August 21, 2021, 09:09:59 AM

Quote from: mo2872 – on August 20, 2021, 03:14:39 PM

So.......where the heck is the orifice tube on these '88's?? 5.0 XR7.......??? Thanks!

The orifice tube is in the line that runs between the evap core and condenser on the passenger side. It hugs the frame rail right above the K-member.

Re: Air Conditioner R134a conversion

Reply #11 – August 21, 2021, 03:04:57 PM

New liquid lines come with an orange (R-134a) orifice tube. The OT is held in NY a crimp in the metal part of the line.

Re: Air Conditioner R134a conversion

Reply #12 – August 25, 2021, 06:17:00 PM

I just used '93 Fox Mustang AC parts for the 351W and Vic Jr in my '83 and routed them like they are in my '93 Coupe. Everything fit and bolted right up.