R134a retrofit for 1975 280 part 2

[Cruzzar]

I thought I would post what I have done to complete my retrofit from R12 to 134a. I ordered a Vintage Air 12" x 24" condenser from Summit Racing since the old condenser was a 12 x 24.  The new condenser comes with #6 and #8 male o ring fittings. Since I am trying to keep this retrofit stock looking as possible I found that you can remove the stock condenser's brackets and reuse them on the new condenser with a little modification. Since the new condenser is slightly wider you will need to slot the 4 mounting holes about 3/16" toward each other. The only other modification needed is on the left side bracket and you will need to make an opening for the #8 male fitting to go thru and removing a small section of the bottom to make room for the #6 fitting. In the process of doing this last step you will need to remove the bracket that attaches to the core support but you still need this support so you will have to modify the attachment point. I made a small bent piece of metal and welded it onto the bracket that kept the hole location correct before I cut off the bottom porting. Here are three pictures, the first is of the stock brackets after unbolting them from the old condenser, then the modified left side bracket and then a close up of the bottom portion.

To attach these brackets to the condenser it is simply a matter of using 3/32" neopreme strips between the brackets and the condenser. If you have ever reset door window glass back into the u shaped window mechanism you know what a grip this process has. Just shoot some Windex window cleaner on the neopreme and brackets and shove them together making sure the four mounting holes align up to the holes in the core support. 

Upon mounting the condenser you will note that the condenser's #6 and #8 fittings are very close to the top air inlet for the cabin and the front bumper bracket. You will need a tight 90 degree #6 fitting (Summit Racing) and a slight trimming of the front bumper bracket's rear most flange. Pictures 4 and 5.

To replicate the hard lines I purchased two 4 ft. premade aluminum (U-Bend-Em) hard lines. The #8  line with male and female o ring ends, the # 6 line with female o rings on both ends. You can order these lines in various lengths but I chose to try to make it look stock hence the 4 ft. length. If you choose the 4 ft. length for the #6 line you will have to be careful when bending that you allow yourself the ability to physically install the bent line in the hole in the core support and around all of the other stuff that is in that area. I used a new drier that came with #8 flare fittings so the original hard line from the firewall to the drier just bolted up like stock. On the other side of the drier going to the condenser I ordered a #6 flare to male o ring adapter which then bolted up to the #6 female end on the hardline from the condenser. 

On the #8 fitting on the condenser I had to trim slightly the metal that surround the cabin air inlet tube in order to get it installed. I  then I bent the tube 180 degrees (use tubing benders on all the the hard lines) so it traversed across the condenser and then thru the core support hole like original where it attaches to a #8 female 45 degree hose fitting. I will use the stock bracket to attach a line clamp onto the tube to reduce vibration as like it did stock.  At the end of this hose I needed to attach to the compressor. I could not find a #8 90 degree fitting with the filler port on the side so I took a 135 degree fitting that I already had that had the filler port on the side and very carefully straightened it back to 90 degrees and installed it. For the #10 line going to the firewall I used a #10 135 degree fitting with filler port but on the other end I ran into a problem. The #10 hardline that is stock in the Datsun is a weird size. It is a #10 hardline but it has a #8 male flare fitting end. So finding a fitting that goes from a #10 hose to a #8 female flare fitting could be a problem until I realized that I already had one on the old hose that I removed. I simply very carefully cut off the metal crush sleeve, got a new sleeve and squeezed it on like any other fitting. This system results in both filler ports to be easily accessible and next to each other on top of the compressor.

In the following pictures I show the bent to fit #6 line already painted and ready to be installed. The next, the # 8 hard line test fitted (I will paint it before final install), the engine side install, and then a pic the # 10 line with #8 female line removed from the original hose. 

If I were to do this again I would see it I could find a condenser that had the #6 and #8 fitting closer to the center of the condenser as that would allow more room to get the hardline on without any interference from the car's body. I might also order a longer #8 hardline and bend it to go around the outside of the condenser as opposed to going across it. 

One last thing I did was to upgrade the blower motor to the 1998 Kia Sportage blower motor. In addition to making the hole about 1/8" larger in diameter you will need to change out the three spacers to new ones to form a good seal. The spacers that I made were out of some 1/2" round stock with a 5/16" hole and .666 long. 

 

Edited July 24, 2021 by Cruzzar