I'm doing an engine swap soon, so had to disconnect AC lines to the front of the clip. Been reading about converting r14 to r134 and sounds like I'll need to do more than change out O rings.
What are the pros/cons of keeping/deleting the AC system all together?
Can I run a shorter belt from the crank if I delete the pump, or will the fan pulley get in the way?
Is factory pump/bracket worth anything? I've heard that it may affect resale if you remove it, but can't imagine a nonfunctional AC would be that desirable.

 

By "pump" .... do you mean the A/C compressor? My '77's (351M) A/C belt only ran on the crank and the adjuster idler and the compressor, I just removed the belt a while back, hung it on a nail as a reminder. I've long thought about removing the compressor and hoses, and condenser and evaporator too in time. I put the whole system in after scavenging from two donors in the '80s, but it's been 20 years since it worked as the compressor or other place leaked the freon out, and I never used it enough to make it worth while tome. I used it a time or two in the '90s on long road trips. The reason I even put it on was the vents didn't help cool, turned out it was that bug shield blocking air flow. If I did remove the compressor, etc ... I'd still have good vents now. I might keep it on though? Not for resale, but I might let a buddy try the R134A, he says a change in drier, a valve, O-rings, & a flush? I don't know that such is worth it to me, I don't see long rides in it's future, just local drives.

 

yes, the compressor.
I was looking last night and assumed the other pulley was connected to something else. I guess it likely is the adjuster idler, so I can just remove that belt and eliminate the parasitic drag of the compressor.
and yes, mostly puttering around town in this truck, so AC will likely not be necessary and retrofitting to R134 will likely be a much bigger undertaking.
Removing all those hoses and cleaning up the engine bay might be reason enough to disconnect the system.

 

Factory A/C is desirable and adds value. but if it's not working and you don't want to fix it you can remove the hoses and compressor and just hold onto the brackets.

If you want to fix it this is the only way to go, I've done two of these kits and I wish I had done it years ago.

76-79 F-Series Truck/78-79 Bronco AC Compressor Kit V8 STAGE-1 | Original Air Group

 

I go back and forth on the fence, a couple times I was ready to just yank the unneeded parts. Really, if the clutch isn't locked, the only drag from the compressor is spinning the weighted drive pulley, it just spins freely and the actual compressor doesn't until the electric clutch is applied. When you remove the belt, you'll see. It has weight to smooth out the compressor "knocks" when it's running.

Stock, in the '80s when I bought the truck, it only had heat and vents, but no dash vents, just the kick panel vents. I cut the holes, etc, took a week of spare time on a midnight shift, stripped parts off of a '73 std cab and a '79 crew cab and used a then new condenser & drier. I'd spend an hour or two after I got up in the afternoons. To this day, it still has the '73's heater core ... (and controls with the "Air Conditioned" script on them) ... as the one from the '79 leaked when put in a bucket of water with any air psi. If I removed the compressor, etc ... I'd still have dash vents and they work now with that bug shield gone. I'd have easier access to the distributor too. If I go far, my '07 is easier on gas and it has great A/C, pulls my trailer nicely too. I once even thought I might repair the firewall, but that would require a whole heater assembly to work ... and then there's defrosting to consider. It's a big hole that the under hood box fills, I cut my firewall with a sabre saw after making a cardboard template from the '79 donor truck after stripping it.

And I think about this too. If I was looking at the issue 20 years ago, before I had the '07, I might would do it. If I was concerned about value, I still would look seriously at it. If I lived in Del Rio, I'd think hard on it. It is from what I see, a better way.

 

When I look at a truck that had factory ac, but all of the under hood stuff is missing, I consider it not having factory ac. Stuff is easier to fix when it's there, and when it's been removed you don't know what's missing. Besides, it will still have all the ac wiring and hoses inside, which amount to the hi/lo heating system at that point. Is it significant difference in value? Probably not, but I would knock like $1000 off the value personally over a truck that was complete with ac even if it was not functional.

As far as what needs to be done to convert, at a minimum compressor oil and drier. The compressor keeps oil in it's crankcase vs newer systems where it has to be suspended in the refrigerant to circulate, but I still swap it in case some gets past the compressor rings there is a chance of it not reacting well. Long term you may need to replace orings. Barrier hoses were a thing at some point due to the size of the refrigerant molecule, but I think most proved out that was unnecessary.

I was not able to find a stated difference in the TXV, even though in theory there should be. in a sense they are also self calibrating based on temperature. I didn't take it as far as calling any of the manufacturers to find out.

 

1973/79 F100/350 & 1978/79 Bronco: THREE different types of A/C

1) Factory installed integral A/C is combined with the heater. The A/C controls are in the same panel as the heater controls.
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2) Deluxe dealer installed A/C is combined with the heater. Has a huge bezel that sweeps across the entire right side of the dash covering up the glove box.

There is a separate 'hang-on' glove box that bolts to the bottom of the dash. The two A/C switches are located in this huge bezel.
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3) Economy dealer installed A/C is not combined with the heater. There's a panel where the two A/C switches are located, panel also contains two registers.

This panel fits into the dash to the left of the glove box.

 

My system has been closed for 30 years easy, except for leaks or seepages? I knew the R134A systems used different compressor oil than did R12, but this is the first time I've read the "why" of it. My painter /mechanic buddy said hoses tended to be OK too. Point of this, is just "Thank You" for a new perspective for me.
"Temperature Expansion Valve" .... I couldn't think of the name earlier.

In view of this, I'm gonna revisit this with him.

What, you do or do not use the 134A oil too?

 

You use PAG oil with R-134. You use R-12 refrigerant oil with R-12. If you convert, best to replace all o-rings, TXV, and drier at minimum with R-134 rated products (and flush out the entire system with alcohol.). As long as you are at it, think about replacing the condenser (they're pretty cheap) and York compressor with a Sanden-style rotary compressor. The old York style may not rob power when it's disengaged, but it sucks it when it's engaged. When a Sanden is engaged, you barely notice any power loss. You can source an York-Sanden adapter on line that bolts to the York compressor mount, so mechanically it's an easy job.

 

Thank You .... this has been a helpful thread for me anyway.