mine did that, was undercharged. i did a conversion on a wifes 70 mustang, everything 134. i only kept the evaporator under the dash. i went with a aluminum sepertine condenser, all new barrier 134 hoses, new dryer, and a new sanden 134 compressor. im in az with temps of 110-120. works great. i did the cheap conversion to 134 and it worked half way for a couple years. the temps and pressure of the 134 are to high for the r12 system. like i said you can make it work but you will be messing with it a lot. they make all the r134 pieces for the older cars and its a direct bolt in replacement. it would be nice for some one to make a r134 complete conversion for the r12 ford trucks.
The condenser upgrade on your 70 Mustang was probably a good idea, but the rest was likely overkill IMHO.
I profusely applaud your thinking about trying to "do it right", and not cutting corners, though.
Many folks opt to take shortcuts and that leads to disappointment. .
It sounds like the lady in your life is "chillin" nicely in her 70 Mustang, so that's what counts.
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try to do it right, hmmm, lets see. i replaced everything, except the evaporator. thats all 134 barrier hoses, new serpentine high flow condenser, new dryer, new expansion valve, plus a new, not rebuilt, sanden 134 compressor. and i evacuated the system for 2 hours and let it sit for 30 minutes then charged it with 134 and its been blowing ever since, and thats in arizona with 120 degree temps. id say i succeeded but maybe im wrong, maybe theres something i missed.
try to do it right, hmmm, lets see. i replaced everything, except the evaporator. thats all 134 barrier hoses, new serpentine high flow condenser, new dryer, new expansion valve, plus a new, not rebuilt, sanden 134 compressor. and i evacuated the system for 2 hours and let it sit for 30 minutes then charged it with 134 and its been blowing ever since, and thats in arizona with 120 degree temps. id say i succeeded but maybe im wrong, maybe theres something i missed.
Nope. You covered all the bases. That's what I meant, maybe you misunderstood.
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Oh, you drive a Hummer? Isn't that just a cute little thing!! My ride is an EMD E-8A. Wanna play chicken! www.lakeshorerailway.org