Automotive Air Conditioning Information Forum

last summer the cooling fan went out (control relay module)
i recharged the system with the two 12oz cans of 134a thinking it was over or under charged

can you tell me the steps on bleeding 134 through the hoses
is there a way to purge the quick connects

Possibly we have been thru bleeding before but...
Close both handwheels.
This answer assumes you have thumb wheels on your quick couplers.
If that is true, first be sure both thumb wheels are closed.
So the quick couplers are mechanically attached to the lines but the 134 passageway to the hose is blocked by the thumbwheels.
Next, open the blue (low side) handwheel.
Next. attach the service hose (yellow) to your 134 can, open the can tapper valve. This will allow the can to pressurize all the way from the yellow hose, across the gauge set, then through the blue hose, down to the closed coupler.
Now gently loosen where the blue hose attaches to the coupler (do not remove) until you can hear/feel some flow of 134. Now snug up the blue hose back onto the quick coupler. Close the blue handwheel. You have just bled the blue hose.

Now, again being sure the red thumbwheel is closed, do the same thing to the high side by opening the red handwheel and allowing the 134 already in the yellow hose to pressurize the red hose. Then crack the attachment of the red hose to the coupler until you hear/feel 134. then snug up that attachment and close the red handwheel. You have just bled the high side.

Now you are ready to charge in the usual manner. Be sure to keep the red handwheel CLOSED during charging. By bleeding the red hose in the beginning, you will not have air in that hose when you bleed the red side back into the low side when you are done charging, as has been discussed before.
There are several ways to do what you want but they all end up the same. Pay attention to what you are doing and think about what substance (air or 134) is going where.

Many of us rig up a so-called vacuum "tree" with a 1/4 male flare tee and isolation valve so that we can easily switch from vacuum to 134 source.
I have an additional Tee and valve so I can attach my vacuum gauge.
The only problem with this is now you have more potential leak points.
A 4 port manifold gauge set also makes things easier, but for the minimal work you do just stick with the setup you have now

hey tbird
my gauges dont have the regular connection where the hose connects to the quick connect
heres a pic
i think there might be a o ring not sure though
can i crack this lose to bleed?

pic

I have a different setup. I am gonna suggest something I have not tried myself. Others will correct me if I am wrong.

With the quick coupler off the resting fitting on the gauge set, and your 134 going up the yellow service hose,and the blue hand wheel open, what happens if you screw the thumb wheel in, that should open the valve and accomplish bleeding

i tried and opening the quick connect with the 134a going in and it didnt bleed
with the 134a still in and my swimming goggles on i cracked the connection at the fitting with two wrenches and it bleed out without a blow out of any o ring

now im set to recharge when the time comes
thanks

OK, there should be an easier way.
I just loosen my hoses a little (with the knurl) right at the quick connect.
You do not have that knurl, but there has to be a way

tbirdtbird wrote: ↑Mon Sep 13, 2021 11:20 am OK, there should be an easier way.
I just loosen my hoses a little (with the knurl) right at the quick connect.
You do not have that knurl, but there has to be a way

I take this to say, he opened a fitting on the actual system. Hopefully, I'm wrong.

Don't think so. Based on the pic, I believe he cracked the fitting where his hose connects to the body of the coupler. I expect it is an ORing connection.

tbirdtbird wrote: ↑Mon Sep 13, 2021 5:51 pm Don't think so. Based on the pic, I believe he cracked the fitting where his hose connects to the body of the coupler. I expect it is an ORing connection.

Hope so.

Odd since the hose on the manifold would do the same.