R134 charging from 12oz cans?

[DHS]

I am about to be charging my 1995 Gmc Suburban. It had rear air but I am eliminating that and only going with front air. I guess is has an aftermarket rear air because it has rubber lines running to the back, Acme brand conversion I believe.

Specs say 2.25lbs, so 3 cans should be perfect. Unless you lose too much buy purging the air out of the line and the little bit you can not get out of the can. Is it a big deal? I did not know if I should buy a 4th can and only add a little bit out of it. I will use the shortest hose I can to go from the can tap to the gauges to limit the loss of refrigerant.

I also am replacing the orifice tube,accumulator, ac hoses and the condenser. I will add 3.5oz oil to the accumulator, 1oz to the condenser, and nothing in the hose. Does this all sound correct?

Last year I replaced the compressor, evaporator, orifice tube, and the expansion valve. I had a compressor failure so I had to do lots of flushing. I did pull the orifice tube today and it was very clean, looked new and only had 2 very small flakes of metal.

Any help or advise is welcomed. I do have a gauge set, and a vacuum pump. Last year to vacuum it down we used a converted fridge compressor but I bought a Mastercool vacuum pump from Advance Auto, so hopefully that will do even a better job.

 

[agoins]

Walmart is the cheapest place I have found to get 134a. Its around 10 a can IIRC.

 

[DHS]

Yea, Walmart or Big Lots both are about the same price.

 

[Carguy99]

if the spec is 2.25 than put in 2.25 not three. the correct charge is critical.
I wouldn't worry about loss. just purge the lines when you are done.

 

[pattenp]

Good luck on finding it at Walmart for $10 a can. I just bought some and it was $14.99 a can.

 

[DHS]

if the spec is 2.25 than put in 2.25 not three. the correct charge is critical.
I wouldn't worry about loss. just purge the lines when you are done.

Well 16oz is a pound, so 3 - 12oz cans would be 2.25lbs with my math at least.

Carguy you made me doubt myself, haha. I had to google oz=lb just to be sure.

edit: I think they use to sell it by the pound but dropped it to 12oz, price probably did not go down though.

 

[mtnkrake]

And if you are buying it in CA you can add $10 to the price for the core charge for the empty can.