Need some help/info on a/c fittings. I'm putting air in my old pickup and I'm using an old hang on unit from a '66 Mustang and I'm getting ready to start figuring out the routing of the hoses and service port placement and the like. I'm using a new Sanden 508 compressor and reduced barrier hose and I'd like to put my high side charge port on the compressor fitting and to do this I'd really like to find a 180 degree fitting with the 134 service port and a barb or crimp fitting on the other end so I can go in a fairly straight line to my condenser but I've not been able to find a 180 with a port. I've found a 135 degree with the port and I can probably make that work but its not my first choice. Do they make a 180 for reduced barrier with a 134 port? Next question is what is the difference between a crimp end and a barb end? Why/where would you use one over the other? Is one better then the other? Will either work with reduced barrier hose? Also, I'm wanting to go through the firewall with the hoses and no bulkhead fittings to reduce the chances of leaking fittings which is one of the reasons for the reduced barrier hose so I can bend it easier and tighter to make the curves. Good or bad idea? Thanks for any and all help!!
This has been the "Go To'' place for A/C conversions for decades give them a call: https://aapak.com/ I have the Mustang unit in my '54 Ford AAPAK can make custom hoses if you know the specs you need.
You can change the fittings on the compressor. If yours point straight back, you can change them for some that point up. By doing so, you can do away with the 180 degree fitting. The aftermarket fittings are the same as for R12 and R134a, so using an older unit is not an issue. You will want to make sure your vintage unit is "surgical room" clean inside the piping, and also make sure you pressure check it before installing it. Use a modern "block" style refrigerant valve to do away with the older style TXVs that have the external sensing bulb if you can. Barb fittings are designed to be used with gear type clamps which are are really unacceptable in "factory" A/C systems. You really require a crimped fitting to ensure no refrigerant leakages. The problem is that you require the correct crimping dies for each specific refrigerant fitting size, plus the hydraulic crimping machine to make the crimps. I would recommend mocking everything up, and bring your hoses to an A/C shop to gave them properly crimped. It will be money well spent. Of course you can purchase a hand crimping tool with dies as well, but if your only going to do this once, it probably isn't worth it.
I just looked up your location, I was going to suggest going to a ThermoKing dealer for fittings. I work in downtown St.Louis and when we do custom A/C work, we get fittings from Central States ThermoKing. They have a catalog with all kinds of neat stuff for A/C. There might be a TK sealer in Joplin. Sent from my iPhone using The H.A.M.B. mobile app
I bought reduced barrier hose and fittings from Yogi's. I purchased a hydraulic crimper from ebay and am reasonably successful. Years ago, the aftermarket kits used hose clamps on r12 systems. The head pressure is higher on 134a so that could be the reason that crimped connections are used now. There are some sellers on ebay of reduced barrier fittings so searching might be the answer.
I used a Mark IV hang on unit in my 1950 Buick. It cools real well down here in the Texas heat. I am sure it will cool your pickup just fine. Also, I used the "barb" fittings and clamps. I bought them and the hose at a local AC shop. Used what he recommended. Two years and probably 3000 miles and all is well. I did not go for neat. Ben
I've used barb fittings with R134A and not had any problems before. Crimped fittings will probably hold more pressure, but if you're over 150 psi on the high side you've got other problems than a clamped hose.....
Haven't played with hot rod AC for a while, but the crimps for R12 were different than the ones on R134. Also, a lot of the R12 were like a flare nut fitting, while the 134 used O-rings. Doesn't really help with your question, but gives you some more things to check out on your install.
The pressures between R12 and R134a are virtually the same, with R134a operating at a slightly higher discharge pressure. Clamps will work, but will leak much more quickly than a properly crimped fitting. Typical refrigerant discharge pressures are usually anywhere from 200 psi to 300 psi depending on evaporator load and ambient temperature. Flare fittings were used back in the 50's and 60's, and later on some commercial systems using other refrigerants such as R-22.
So it looks like I need to look for a crimped fitting instead of a barb. Another thing, the guy at the A/C shop said that I will need to mock up my lines and get the fittings properly oriented. If you have a flare fitting, aren't they "self-orienting" so to speak? What am I missing? Also what to you all think about using the reduced barrier hose and going through the firewall without bulkhead fittings? I figure thats just one more place to leak.
Yes, for any type of fitting that is not 180 degrees (i.e. straight), you will need to mark the "index" of fitting relative to the longitudinal axis of the hose. Think of the hose sticking horizontally out from the center of a clock face. The index of the fitting (say for example a 90 degree fitting) could then be at the 3 o'clock, 6 o'clock, etc. position. You can't legally use flare fittings, but think of the nut (male or female) as part of fitting. (It cannot be removed from the fitting). Again, if the fitting is straight, no issues, but if anything other than a straight fitting is used (45 degree, 90 degree, 135 degree, etc) you need to place a mark along the fitting crimp end and hose end to identify the "angle" or index of the hose with respect to the fitting. Yes, you do not need to use a bulkhead fitting. Find a large enough grommet to p*** the hose through with the fitting already crimped on. We did this all the time for all sorts of AC systems for forestry, construction, emergency, military, bus, etc. Some typical AC fittings. Type of grommet we used. Do you know what size hoses you are using? Typically systems will use the following sizes: 1. Suction line (from evaporator outlet to compressor inlet): #10 or #12. Some systems like GM had an "ac***ulator" (large aluminum reservoir) in between the evaporator and compressor. Not sure what Ford did. 2. Compressor discharge (from compressor outlet to condenser inlet): #8 3. Liquid line (condenser outlet to thermoexpansion valve/TXV): #6. Depending on your arrangement, we may need a hose the TXV to the evaporator, but it is the same size. Since the 90s, most automotive AC system use a TXV referred to as a "block valve" as it looks like a block of rectangular aluminum, and often these are connected directly to the evaporator coil. AC block valve.
I have used two of the old add-on style A/C evap units. One in my COE and the other in my 52 GMC pickup. Both with TXV as originally used. I use R-134a and both have recycled condensers as well. Both had custom hoses made up, or adapted some of the original hoses. COE uses a Sanden, GMC has the GM R-4 compressor (because donor engine had it and it works for now). Recommend that you use a safety pressure switch, it will stop compressor if low refrigerant or if pressure is too high. Either condition can damage your compressor. The custom hoses were the most expensive part of the A/C system. The old add-on evap unit works fine with R-134a even though the TXV is technically designed for R-12. Just ensure you charge up using pressure gages and monitor both high and low pressures. R-134a works best with a R-134a condenser, although an old R-12 tube and fin type will work with less than optimum results. Also R-134a is much more sensitive to overcharging, so if in doubt leave slightly undercharged.
Ben, what did you do for mount and pulley on your straight 8? Does Vintage Air supply a bracket and compatible pulley for the wide belt? Thanks Ryan
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