Last year, my A/C was not blowing cold. Threw a can of 134 in it and all was well.

This year, same thing, but now not so cold.

I had the whole cab and inner heater box off when I repainted the truck last fall.
But I did not have any of the a/c lines open

I am wondering if the blend door is not fully closing.

Can someone point me in the direction of the blend door and the vacuum pod for it.

 

Was the truck converted to 134a previously and then you topped it off wih 134 later...
It could be that the blend door isn't closing all the way, but I don't think I so.
R12 was a colder refrigerant, but 134 is less harmful to enviroment.
Anyway, when you add refrigerant yourself, you also add air into the system. That means that it will still compress and cool, but not as well. I've had great AC systems leak very slow, and I top them off, and then not cool as well. It's the air.
My reccomendation is, use a couple washers and vise grips to pinch off flow to heater core, then see if the cool air gets colder. If it does then blend door not closing all the way.
I thought it was the defrost, floor actuator that was the vacuum, as well as the "off" door. Two separate items, and blend door was still cable. I haven't been under the hood of a 93+ in a long time so I'm a little rusty with the exact details.
Make friends with someone with an AC machine. Get it sucked out and a vacuum check performed on the system, then fill it complete. Maybe even change some orings while its evacuated.

My 90 needs a service as well. It cooled just fine last year but has slow leak from hose/oring. Yay. It cycles the pump way too much because I have filled it like 3 times last year and now it just cools, at a stop it gets almost warm when on high. Medium it can maintain cool sorta.

 

Was the truck converted to 134a previously and then you topped it off wih 134 later...
It could be that the blend door isn't closing all the way, but I don't think I so.
R12 was a colder refrigerant, but 134 is less harmful to enviroment.
Anyway, when you add refrigerant yourself, you also add air into the system. That means that it will still compress and cool, but not as well. I've had great AC systems leak very slow, and I top them off, and then not cool as well. It's the air.
My reccomendation is, use a couple washers and vise grips to pinch off flow to heater core, then see if the cool air gets colder. If it does then blend door not closing all the way.
I thought it was the defrost, floor actuator that was the vacuum, as well as the "off" door. Two separate items, and blend door was still cable. I haven't been under the hood of a 93+ in a long time so I'm a little rusty with the exact details.
Make friends with someone with an AC machine. Get it sucked out and a vacuum check performed on the system, then fill it complete. Maybe even change some orings while its evacuated.

My 90 needs a service as well. It cooled just fine last year but has slow leak from hose/oring. Yay. It cycles the pump way too much because I have filled it like 3 times last year and now it just cools, at a stop it gets almost warm when on high. Medium it can maintain cool sorta.

 

97 was 134

 

did you put gauge set on it?
without high/low pressures, you are really just walking around blindfolded

 

Ok.
I think you have a leak and lost fluid still.
Pinch off heater core and see if it helps. I use two washers and a small cclamp during the summer.
I've only had 1 vacuum actuator go bad and it was a jeep. I think the vacuum actuator on heater box in enginebay is the "off" and "max AC" It should have no vacuum to it to shut the hot air off from the rest of the box.

Hopefully someone else will chime in soon.

 

If it's low on freon, it will most likely be cycling compressor clutch more than normal..

 

Outside temp is about 80*
Inside temp only gets to about 67*
Engine is on high idle(1200rpm)

Compressor runs for 20-30 second then off for 3-5 seconds
Low side pressure is 45-50 compressor off
25 with compressor on

Those numbers seem low to me, but it has been a while since I have done A/C work.

And NO, I do not have a high side gauge

 

low side pressure with compressor running should be closer to 40 PSI at 80 degrees,
high side should be 190 to 200,
and center vent should be 44 to 48 degrees.
these are with AC setting on max with blower on high.

you are either still low on freon, or your compressor is going bad.

 

Sounds to be a little low, you need to maintain at least 28-30 on low side to keep the low pressure switch form short cycling the compressor..

 

I'll add some more freon and see what she does.

EDIT: Went out to add some more freon and the low side is reading 35-40 and the compressor is NOT cycling(just staying on)
That is at an idle, blower on high and A/C on max.

 

That's air in system or weak pump.

 

Ya, you have a leak.

You can either beep pumping air and 134a into it with bad AC performance, or have it evacuated, fix the leak, pull a vacuum on the system and recharge. That's the only way to make your AC work properly.

Also, don't use stop leak or other junk. It screws up your system and can cost big money to clean out and might even ruin your compressor when the junk hardens in there. Only use pure 134a with no additives.

Good luck!

 

also one other things i asked my old man (certified master hvac man for EVERYTHING) and he said that the compressor is likely leaking, no way to know for sure without being there but that it is very likely(he said 90 percent) that it is the compressor and that even if it isnt that it would be worth while to change the compressor while you are at it. Anyway he said they make a rebuild kit for the compressor, dont get that just get a new one. he also said you should get a guage kit that has high (red) low (blue) and a transfer (most commonly yellow) so that you can do it yourself, this is assuming you have a vac pump, if not than its really not worth doing it yourself than. he said if you do do it yourself than you should fill the cold side with the can of r134a upside down to get the liquid and the high side with the bottle standing up. he said he hoped his experience could help you

 

Trying to find a place around me that does A/C work. Most places are scared of A/C