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#1
04-30-2016, 02:56 PM
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1972 280sel ac issues
I have a 72 280sel It has been to the dealer and another Benz centric repair shop. They both put die in the system and a couple leaks were found and fixed. The evaporator apears leak free (no die seen) The system will not hold a vacuum.
Does anyone have any thoughts on where I might look or what I might be missing? Can the evporator be isolated to see if it is the source of the leak? Are the evaporators the same part for any of the styles / brands of AC systems that were used in the 280se and 280sels? How can I be sure which brand of AC system was installed on my car? I would grateful for any insight anyone might have Last edited by geen; 04-30-2016 at 03:11 PM. 
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#2
04-30-2016, 03:15 PM
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Freon leaks quite often occur in the refrigerant lines at the connections. These connections have O rings that leak over time. The lines themselves (especially if they are original to the car) also leak.
You might also try to find an AC shop that still uses an "old school" electronic leak detector. The AC system would be charged with a small amount of freon and the leak detector is then used to scan the entire AC system and if a leak is detected the leak detector begins to buzz. The electronic leak detector resembles a small hand held geiger counter. I would look for a shop that specalizes in AC only as most general repair shops and the dealer will not have such an "old school" leak detector. Last edited by BWhitmore; 05-02-2016 at 11:53 AM.
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#3
05-02-2016, 10:30 PM
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If they are using the dye method they will almost never find a small leak. The electronic detector is the only way to go.
I have used one of these many times and they will find the smallest leak. They have a small 'wand' that you touch the connections with. A tiny vacuum inside the unit sucks in air and samples it. ANY freon or R-134 will be detected. You will hear a steady beep. When the speed of the beep increases you have found the leak. It is usually an 0-ring that has failed. But don't stop just because you have found 'the leak'. Check every connection to make sure there is only one leak. And if you can't find a shop with such a detector you can pick up one off of Ebay for about $50. Then, when you are through with it, sell it again. I have even used these detectors to find air leaks in a 300SEL 6.3 suspension. Someone on here suggested it and it works! All you need to do is inject a bit of R-134 into the system through the air tank. Some shops will tell you the use of these detectors is not legal because you have to inject gas into a leaking system and the EPA freaks out over this. I don't know about this; I do know that these detectors, sometimes called three-gas detectors, work better than anything else.
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#4
05-04-2016, 12:13 AM
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When I was trying to find a leak a friend temporarily filled the system with propane (which obviously is flammable, although some people use it as a refrigerant). Since the system was at operating pressures it was relatively easy to find the leak by spraying all the connections with soapy water. Found bubbling at the condenser connection. AFAIK propane is compatible with R12 (ie you do not have to flush the system to use R12 after propane), but I don't know about R-134a. Do some further research if you want to go that route.
__________________
Csaba 1972 280SEL 4.5, silver
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#5
05-04-2016, 05:15 PM
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AC leaks can be difficult to find.
Electronic sniffer leak detectors are frequently used in addition to ultrasoinc leak detectors that listen for leaks. Soap only finds the major leaks so that is pretty much out. It doesn't take much freon to charge a system just enough to check for leaks. I've gone so far as to clamp off AC hoses to break the system into sections then look for pressure drop.
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#6
05-05-2016, 03:35 PM
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Geen, I apologize for butting in and thread jacking... is there anyway you can take a picture of the exact location of your evaporator? I'm installing AC in my w108 and am trying to figure out the exact placement. Thank you very much!
__________________
-68 280se -71 BMW 2002 -61 Tbird Convertible -15 E63
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#7
05-07-2016, 02:12 PM
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well I did not have to deal with the evaporator so I am sorry cant tell you anything about placement other that its in a box under the dash kind of behind the glove box insert.
I found a guy that installed my new drier and replaced some lines, charged it and it appears the problem is solved. 37 degrees at the vent. The guy left it hooked up overnight and no pressure loss.
__________________
 1972 280 SEL
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#8
05-07-2016, 03:49 PM
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#9
05-07-2016, 04:38 PM
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I don't know the brand of A/C the 108 had under the dash but I am pretty sure the blower motor was made by BEHR.
Check for 108 blower motors on Ebay. These things look like a big enclosed single cage blower with the motor coming out of one side.
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#10
05-09-2016, 06:18 PM
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I am still using R12. I think they ran 3 brands of US installed ACs in these cars. 1 is Behr, 1 is themal King? And 1 is Frigid air or Frigid King. I think mine is Frigid it uses a GM A6 compresser.
__________________
1972 280 SEL
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#11
05-09-2016, 08:37 PM
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But in the end it will not matter which brand it is is. They were almost all made by the same companies in Fort Worth: Frigiking, ARA or Clardy. And all worked the same way. Volkswagen also had a plant in Fort Worth and marketed their A/C's under the 'COOL' brand. But I think they only made units for VW and Porsche.
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#12
05-09-2016, 11:50 PM
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Quote:
__________________
-68 280se -71 BMW 2002 -61 Tbird Convertible -15 E63
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#13
05-11-2016, 02:01 PM
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