dont see anyone knocking you. im in arizona and did a couple conversions, blew ice cold until it got to 105 and above. as for the 75% rule, well they stopped that a long time ago, to many compressors were burning up. when i do mine ill either do a full r134 conversion, hoses, compressor and condenser, or do the r12. oh i also have the vacuum pump to evacuate the system, and a large bottle of r134, plus gauges.

 

Eddie, could you give a quick overview of the vacuum process? I plan on doing this to my '96 this coming weekend. I already have a cheapie Harbor Freight vacuum. Would that one be good enough? TIA

Roger

 

One shop I deal with does a quick change simply to get an operating AC setup for the season: They evacuate the system, essentially "flush" it with 134, then evacuate it again, and recharge, including an oil charge... NOT a great fix, but one that you can use as a "patch" till you can overhaul the system properly during winter maintenance...

Scott

 

If you do an R134a conversion, get an extreme temp orifice tube.

 

Which one is that? They only have a red and a blue listed, and the difference is t he orifice size: One is .067, the other .065 IIRC...

Scott

 

Look under a 1997 F350. They list one that is for 105°+ temps.

 

Checked it at Pep Boys- $35! Guess I'll be sticking with the smaller orifice one, as one person recommended(Red, IIRC)

Thanks!
Scott

 

I thought it was a total crock and did nothing, until I installed one in my 94. The AC at idle in Southern California traffic last summer held up awesome, no spike in temperature at lower RPMs

 

There is a company called Redtek which sells R12A which can be mixed with either R12 or R134a refrigerant. I recently used it to charge my 89 F150. All I had to do was jump the compressor and it sucked the can right up. AC blows cold now! Didn't have to convert to r134a.

I've read numerous times that a vehicle designed for R12 won't get as cold with R134a so that's why I didn't want to convert. I never hear anyone mention this Redtek 12a stuff but it worked wonders for me!

 

I do an abbreviated version of this and have had zero issues with my conversions. My 89 F350 will blow 32 degree air out the passenger vents sitting still. I get 40 degree air out the drivers vents cruising 65mph.

Nobody seems to like the R134 conversions but I've had great luck with them.

Jeremy

 

A conversion has to be done properly, that's the main problem. People usually do them on their own and skip steps, don't pull vacuum, don't let it sit long enough under vacuum to make sure there are no leaks.

I converted my dad's older truck, it friggin snows in his cab, and that's with southern California desert heat.

 

I replaced everything except the hoses when doing the swap to R134a... still doesn't work right, I mean, everything works, but the system still leaks.

And remember to replace every black rubber o-ring with HNBR green ones.

 

Not meaning to be contrary - but here's what I did on the '87 mainly as the result of installing a later model engine...

- Disconnected every fitting I could find under the hood...
- Removed and discarded the orfice tube and acuumulator/drier...
- Thoroughly flushed the evaporator and condensor with commercial AC system flush...
- Installed a new orfice tube and accumulator/drier
- Replaced the compressor switch on the accumulator with one rated for R134a...
- Replaced the compressor with one rebuilt to R134a specs and prelubed with PAG oil.
- Installed new hoses on the compressor along with R134a rated seals on all fittings
- Pulled everything down with a vacuum pump
- Calculated the correct volume of R134a based on conversion charts available online
- Charged the system with leak detector and freon with the reduced amount of freon.
- Compared operating pressures against a recommended pressure/temperature chart.

Everything is within specs found on numerous sites and has been blowing 43°F air for a while now. No, I didn't change the condensor, but it seems to working just fine as it is. I must note, however, that there were signs that a previous owner may have had a R134a conversion done on it so they might have already swapped the condensor.

 

It's been a few months. Everything still blows nice and cold. When I had it charged the shop said vent temps were at 34*. This summer working in LA will give it a test. Might need a new fan clutch (233k miles) but that's the only issue I have because sometimes in traffic it's not quite as cold.

 

That's normal with these old trucks. The variable orifice tube is designed to even out pressures during all driving conditions so you don't have a drop during low RPM or traffic.