How to recharge the A/C - PeachParts Mercedes-Benz Forum

Matt SD300 · #1 07-31-2009, 01:43 AM

On a 1984 300SD....

dannym · #2 07-31-2009, 08:06 AM

Didn't you just go through all of this nonsense with your Indy?

Matt SD300 · #3 07-31-2009, 03:09 PM

Quote:

Originally Posted by dannym

Didn't you just go through all of this nonsense with your Indy?

HUH???????????...Never been to a Indy....I turn my own wrenches....

So nobody knows how on this forum??....................

rrgrassi · #4 07-31-2009, 03:17 PM

Did you replace components?

Do you have vacuum pump and guages?

Tell us what you did so we can help you.

Matt SD300 · #5 07-31-2009, 03:26 PM

Quote:

Originally Posted by rrgrassi

Did you replace components?

Do you have vacuum pump and guages?

Tell us what you did so we can help you.

A/c works fine just needs to be filled/charged..........

tankowner · #6 07-31-2009, 03:26 PM

Quote:

Originally Posted by Matt SD300

So nobody knows how on this forum??....................

More info required.

Have you done something? Do you just want to add more refrigerant? What's the deal? Plenty of people here know how - what we don't know is what exactly it is you want to know.

tankowner · #7 07-31-2009, 03:30 PM

Quote:

Originally Posted by Matt SD300

A/c works fine just needs to be filled/charged..........

Do you have a gauge set? Or, at least a single hose to transfer with? Is this a first attempt?

zeke · #8 07-31-2009, 04:08 PM

If you just want to charge it, it is pretty straightforward. Can tapper, gauge and hose with the proper fitting (R12 I assume). Pretty cheap on fleabay
Get some refrigerant - if it's R12, you will have to get a license - some searching here will lead you to an online certification program.
Then tap the can and purge the lines by opening the valve in your gauge until the line is filled (gauge and hose) then connect the hose to the low pressure fitting (right in front of valve cover on w123 models). Start the car and turn the AC to max then open the valve in your gauge and add the proper amount of refrigerant. Low pressure should be 35ish? If you are really completely out of refrigerant, you may need to jumper the pressure switch on the drier to engage the compressor by running a wire between the 2 leads.

BUT, I think you should really be asking why you need a charge in the first place. refrigerant doesn't get "used up" - it leaks out, and if you have a leak, you will be spewing refrigerant all over town!

good luck!

Hit Man X · #9 07-31-2009, 08:05 PM

If you're asking... you need to farm it out or keep reading before you leap.

leathermang · #10 07-31-2009, 09:45 PM

I am pretty sure Matt is doing some good natured TROLLING....
To say it is fine but needs to be refilled is an oxymoron....
it had to leak something to get to that place...
so fixing something is in order...

Matt SD300 · #11 07-31-2009, 10:11 PM

Nope.....Just want to make sure is its full!!..........

Matt SD300 · #12 07-31-2009, 10:14 PM

Quote:

Originally Posted by zeke

If you just want to charge it, it is pretty straightforward. Can tapper, gauge and hose with the proper fitting (R12 I assume). Pretty cheap on fleabay
Get some refrigerant - if it's R12, you will have to get a license - some searching here will lead you to an online certification program.
Then tap the can and purge the lines by opening the valve in your gauge until the line is filled (gauge and hose) then connect the hose to the low pressure fitting (right in front of valve cover on w123 models). Start the car and turn the AC to max then open the valve in your gauge and add the proper amount of refrigerant. Low pressure should be 35ish? If you are really completely out of refrigerant, you may need to jumper the pressure switch on the drier to engage the compressor by running a wire between the 2 leads.

BUT, I think you should really be asking why you need a charge in the first place. refrigerant doesn't get "used up" - it leaks out, and if you have a leak, you will be spewing refrigerant all over town!

good luck!

Sweet!!!........Thanks....Zeke!!!..........

Cervan · #13 08-01-2009, 01:47 AM

charge by sight glass, if you see bubbles it needs more. if its clear you have a condenser blocked or evap blockage.

leathermang · #14 08-01-2009, 09:44 AM

The Mercedes Factory Shop Manual specifically says that using the sight glass is not reliable for this procedure..
You have a real chance of overcharging using what Cervan said.... which is about the worst thing you can do... they will function just fine many ounces under the optimum charge ....but one ounce above starts to really work the system way too hard.. and how often in overcharging would you manage to get it ONLY one ounce over ?
Anyway, charge by pressure or temperature at the vent... but go really slow because there is lagtime...
Just as so many in this thread have commented on... I think something is amiss in the communication process... how many questions of the physical situation were asked and not answered by the OP.. ?
When doing this backwards... be sure to have a good fan blowing on the condenser.... this is also specified in the FSM on AC by MB... Windows should be open and blower on High... though when later wanting to brag on how low the system will go you change to low blower to find that... I am assuming you have a pencil thermometer to stick in the center vent for this procedure ?