So I have bought a lot of replacements AC parts for my TD. I plan on replacing everything but the lines, evap and condenser. I have 4 cans of R12 that I plan on using.

So my question is..
My TD has R12 in it already. The comp does not come on but I can hot wire the clutch and force it on, I assume it's low on freon. I can push on the shrader valve and there it defiantly still has freon in it. Should I try to ad some R12 to it or do a rebuild like I planned?

In the perfect world I would recover the R12 in it then check for leaks and service with R12. I do not have any way of recovering the R12 that is in it and I can't pull a vac with freon in the system.

Any thoughts?

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08 R320 CDI current

Past
95 E420
87 300D Turbo 5spd
90 300TE
83 300SD
85 300TD
92 400E
85 190D

I just finished A/C ON my 83 300td ,new dryer and compressor.My mechanic cleaned out the lines ,really naste junk if original in stuff in their.It was denatured alcohol I believe ,funneled it in the blew it out with an air hose ,then continued an air hose connected to the line and walked away for 30 minutes or so,he says that gets it clean as new .Then reattaches the lines to the compressor and adds oil ,dye first ,then its ready for the 134.My pain was getting the center vacuum element to work the center vents ,ran that down ,then realized it needed a new main vac hose.If your looking for everything to work as for as a/c controls you might want to ckeck first your vac pressure from your pump ,then replace the main vac pump hose that goes to the brake booster .It made tons of difference in the controllers and will circumvent any troubles when your a/c starts working.DIESELGIANT GIVES A REAL GOOD HOW TO.

Sounds like your just low on freon. Do you have gauges. You might just have to add and go. If it isn't broke don't fix it. LOL

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92 300D 2.5L OM602 OBK #59

x2
only way lines get gunk in them is if someone adds it...
a leak will pull water into the system when the pressures are very low.
water will interact with the oil and the refrigerant causing gunk! and more leaks.
if you have original 12 in the system, you are VERY lucky! (odds are good that if it's still 12, it's been topped up over the years.
anyway, I'd start with a set of gauges and see what the pressure is sitting at.
if it's above 100psi, you should be good on charge, time to follow electrical issues.
if it's below 30, you have only a touch of gas in there, and you will need to remove it and or pressureize it with Nitrogen, or some other dry gas, like CO2 or Helium and start looking for leaks.
once the leaks are found, you can decide if you want to fix them, replace the hoses, or flush and repair... of course, if it's below 30, but still pressureized, above 0 you can just add in 12 and go... but you will be knowingly filling an R12 system that has leaks in it...
if you can handle that on your conscience, I'm good with it.

I have gauges coming in the mail. I will check the pressure. I only assume it has R12 in it because all the ports are original R12 and the PO never mentioned having it switched. Plus there are no conversion stickers under the hood. So I could likely just add R12... my concern is how cold it will get. I know I am at a disadvantage with the wagon being a larger area to cool. I like the AC to be too cold on hot days.

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08 R320 CDI current

Past
95 E420
87 300D Turbo 5spd
90 300TE
83 300SD
85 300TD
92 400E
85 190D

it's not how cold the air is in a 123/6, it's how much air there is and how much it's mixed with outside air that's the biggest problem.
our cars have a small blower, and a big car. the ac is matched to this small blower.
R12 is the best cooling you are going to get, so if you can, have your windows tinted, and cut down the solar gain your car is trying to cool. it'll help.

Hey John

So in this case is recovered refrigerant reuseable?

Recovered refrigerant is ABSOLUTELY reusable. It depends on the machine used as to how much processing it requires. In the wrecking yards they have simply used recovery machines that suck it into a cannister. It then needs processing before ready to reuse. MOST recovery is done with a recovery/recycle machine. While recovering, it is dried and the oil is separated. The resulting R12 is put into a tank that can then be put directly back into a system.

in my area there are several recyclers with R 12 in them for sale in the 300.00 range.
these machines will pull freon out, seperate the oil, filter and remove acid,etc. and store the clean R in a recovery cylinder. cool deal

Yes, I have two such machines that are identical. One I use for R12, the other for R134. They REALLY become handy when you need to open a charged system for leak repair. Not only do they let you do the repair without losing refrigerant, you get to do it legally..... Obeying the law! Now there's a novel concept for you.

I agree that the first thing you need to do is get gauges (which you stated you have on order). You can then reasonably determine how close to a full charge or how low of a charge your system has. You can also jump the compressor to see what the pressures show (assuming you have a reasonable charge). But in all likelyhood your system is very low, thus the reason the compressor is not spinning.

If the system is low, it means it has a leak. If you want the AC charge to last for more than one season (or perhaps even a few weeks or days) you should really fix the leak.

I bought a recycle machine like Larry and John have talked about. I got it cheap off of Craigslist along with some other AC tools. You just have to be on the look out. They are out there for reasonable prices. Many shops want to get rid of them as they no longer service R12, that is how I picked up mine.

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2009 ML320 Bluetec
1985 300CD
1981 300TD

Past Mercedes
1979 300TD
1982 300TD
2000 E320 4Matic Wagon
1998 E430
1984 300SD
1980 300SD

Is this of any use to me?

http://indianapolis.craigslist.org/tls/1760771900.html

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08 R320 CDI current

Past
95 E420
87 300D Turbo 5spd
90 300TE
83 300SD
85 300TD
92 400E
85 190D

It may be exactly what you need if indeed you do have a significant amount of refrigerant left in your system. If you plan on working on ac systems more than once (as in multiple cars) then it may be worthwhile to spend the money on one.

You need to find out if there is any freon in the recovery tank of that unit. If so, what variety? Hopefully r12. There was about 10-20 lbs in the one I bought! You don't want to deal with having r134a in there if you want to recover the r12 in your system.

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2009 ML320 Bluetec
1985 300CD
1981 300TD

Past Mercedes
1979 300TD
1982 300TD
2000 E320 4Matic Wagon
1998 E430
1984 300SD
1980 300SD

I bought it. It's a white industries 01050, anyone know where I can get a manual?

__________________
08 R320 CDI current

Past
95 E420
87 300D Turbo 5spd
90 300TE
83 300SD
85 300TD
92 400E
85 190D