so i went down to the local auto parts store to get everything i need to convert the system. BUT the vacuum pump didn't have a hose ok so i am leaving at 7am and need to try to make the A/C work at least somewhat, i've rear about and am gonna search for the thread, where you clean out the box under the dash, any idea if that would help? also i expect to hear no, but is there any way to do the conversion without the pump? i rented some kind of flush thing hoping that would do it but don't know.

 

ok so i should have looked a little closer, it's already got the retrofit fittings on there for the r-134a. so apparently someone already switched it, so i guess i will add some more of the refridgerent and go from there, any other thoughts on the subject, anyone?

 

You should be able to add more R134a. I would see if they have the kind with the dye - easier with a light to check where your system is leaking in the future - so my son who is a mechanic states. Of course you need access to the light . My system is still R12 and has just quit working - I believe due to a small leak. I have the tell-tale signs on the expansion block of oil and dirt accumulation - So we are going to replace it and change over the system to R134a. So what he needs to do is 1. pump the system down to remove the R12. bring the system to atmosphere and then replace the expansion block and install the R134a fittings. Then charge with mineral oil, R134a, and dye. Apparently the amount of R134a that is required is slightly less than what was required for R12.

I guess my thoughts are that you ought to check the expansion block if you haven't already... My 2c worth

 

ok while it may still need more r134 i just cut open the box to clean out the stuff in there and there wasn't much in there, but there is a flap that seems to open right out the the fender, when it is flipped the other way it closes off the vents on the right hand side of the box under the dash, this flap seems to be stuck in the position where it lets that outside air in.... any idea what i am saying?

 

I will have to let someone else chime in. I haven't tore mine down to that point. I would imagine that the door is for fresh air?

 

That flap sounds like your "recirc door". It is normally open at all times to outside air, until you go to "max a/c". It then closes to allow the interior air to recirculate. Even if it doesn't work at all, you are better off drawing in fresh air all the time, and you'll probably never notice it's not working.

 

Spoken like a true Northerner!

Try that in Florida or Arizona and I bet you notice a difference. If given only one option, it would definitely be re-circulated air for me.

 

ok so here is where is stand, i added 3 cans of r134a and other than when it was filling from the can, never got a reading above 22.5psi (ambient air temp about 80-85) after i turned the truck off, i heard a gargling/hissing noise (very faint) from the compressor. i worked on some other things just finishing up with them and came back about 10 minutes later and the noise was still there, it sounded kinda like when you open the bottom of an air compressor to let out the air and water and it kinda pops the water fisses a little air, gets held up and pops again (hope that made at least a little sence) i guess i will find out in the morning if i have a leak there if all the freon is gone, i was hoping it was the highside pressure and low side pressure equalizing.

 

Sound like you have a large leak,did you add dye and do you have a black light, to show the dye?

also have you looked at the condencer? That were i found my leak!!!

 

You make a good point.

 

i would suggest using estor oil in the system it is compatible with 12 and 134. also much easier on the old style hoses.