91 Silverado AC conversion R12 to 134a? (truck, purchase, replace, California)

[Ultrarunner]

Coming home this evening the AC compressor locked up on my otherwise very nice 91 Silverado Styleside.

With the change in refrigerant since 1991, I imagine fixing will not be as simple as a new compressor and a can of R12.

Anyone here converted an older GM truck to work on 134a?

[GarageLogic]

To do it right, you'll need a qualified and equipped service center to suck out all the R-12 (and any shrapnel), then recharge the system with 134a. If you want to redneck it, you can do it yourself. And though I won't recommend doing it, I've seen a lot of DIY redneckings last a long long time.

[Ultrarunner]

I pretty much do everything myself... have not done any AC other than replace the compressor and drier in my 68 mustang decades ago and then had a shop evacuate and charge... that cost me $40.

I've heard the cost ballparked for what I want is over a $1,000

PS.... I'm in the SF Bay Area of California.

[MckinneyOwnr]

If his compressor locked up, he'll need a new one. There won't be any R12 in the new one (and what is in the lines will be pretty much evaporated.)

Just get a new compressor and dryer, then a retrofit kit, and you should be fine. I have done this on all my cars from that era.

[Ultrarunner]

Thank you...

[Electrician4you]

Don't forget to change the inline filter in the AC line

[ukrkoz]

OP, you can manually un-seize compressor. I had it done on several. Don't rush into tossing it. Actually quite easy to do, remove it, get on the bench/vise steady, figure out how to get good purchase of the shaft without damaging it, add some oil to the line connection holes, and start rocking it back and fore. At some point you may see oil start sinking into the compressor and then you add more and then it boom goes... Spin it by hand adding oil as many times as you manage by hand, and it's back to use.
But that is beyond the point, as there is some reason, your system ran low on freon/oil mix. As low oil is what causes seize.
Unfortunately, if you want to use 134, you must have system completely purged and cleaned, or it will gum up.
Now there is a new freon type available, forgot its name, something like carbon based... They say it's a much better alternative to 134.
Either way, you MUST resolve system leak first, or this will turn into a money pit.

[need4speed2012]

You'll need a compressor, accumulator, expansion tube, o-rings, correct pag oil, 134a conversion kit, flush and evacuate and recharge adding the correct amount of 134a and not the same amount as required for r12.

Parts and labor done correctly around $1000.00.