91 Ford Bronco 351 Air Conditioner Question

Not far off on the pressure readings, but the low side shutoff could be a little lower, say 22~25 psi. If the accumulator (receiver/dryer) is getting cold & wet, the problem is most likely under the dash with the BDA (Blend Door Actuator).

It's hard to tell without looking at high side pressures.

If the conversion was done by a competent shop or tech or even me, the reading would indicate low charge.

But if the accumulator wasnt changed and the system wasnt properly evacuated first, it may indicate contamination. Usually the orifice clogged by mix of incompatible oils, which would be indicated by high pressures (high side) before the orifice tube.

If you want to roll some dice, dump in another can of 134a and wait for the compressor or high side hose to blow.

How much 134 did you put in, and how much R12 does it call for.. 134A capacity should be 80% of R12.

{blush}

Yeah... didnt mention that, did I! SKC is right... cold accum is first thing to look for. If it's cold it's good. And the air blend is the problem.

Well, tomorrow I should have some more information, I know that the evaporator is not getting very cold, no condensation on the accumulator either. But I should have a good set of gauges tonight to get good accurate numbers both low and hi.

Thanks again.

Backyard Mechanic wrote: