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85 300D
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Discussion Starter · #1 ·
I'm back again and ready for more abuse(from this car that is). I need to replace the expansion value and one other part of the A/C system before I charge it back up and see if the compressor is any good. In the MB manual I purchased it says the first step besides draining the A/C system, which I assume means removing the freon, is the remove cover at right under instrument panel. It then lists a group and instruction number. The problem is this specific instruction is not listed under that group. Nice job Mercedes. Anyway can anyone explain to me where this cover they are referring to is. Thank you in advance.

David
 

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W-1-2-3 Go!
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If you said "right under instrument panel" that could mean two things.

1. The right side underdash panel (removes with 3 metal screws and 2 plastic ones, the plastic you turn a 90 deg angle either way and pops off).

2. Right under the dashboard/instrument (pertaining to the location) panel, meaning the opposite side (left side) underdash panel, the panel that covers the steering column inside, same panel just above your legs when you're driving the car. Also removes the same way with 3 metal and 2 plastic screws.
 

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85 300D
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Discussion Starter · #3 ·
I looked under the panel on the driver's side and did not see anything like MB service manual was referring to. Can anyone help me locate the expansion valve or for that matter the receiver drhydrator. Thank you.
 

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1985 300 SD
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290 Posts
The receiver/dryer/accumulator is located on the side of the car that has the injection pump. It is sort of recessed in front of the tire on that side and is recessed somewhat and is held in by one sheet metal screw. Look behind the headlights.

Joe

I looked under the panel on the driver's side and did not see anything like MB service manual was referring to. Can anyone help me locate the expansion valve or for that matter the receiver drhydrator. Thank you.
 

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Expansion valve is under passenger side panel.
 

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I am working on mine too (84 300D). Be careful when taking the smaller hose (blue nylon hose)
out. I broke the fitting on that hose since it was so tight and now I have to buy a new #6 hose & fittings. I hope this picture helps..
 

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1984 Mercedes-Benz 300DT; 1980 Mercedes-Benz 300SD
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When I removed my glove compartment box, I could easily see the expansion valve, do you need to remove the kick panel on the passengers side to remove it?
 

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1995 E300, 1985 300TD, 1981 300TD, 1980 240D
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The receiver/dryer/accumulator is located on the side of the car that has the injection pump. It is sort of recessed in front of the tire on that side and is recessed somewhat and is held in by one sheet metal screw. Look behind the headlights.

Joe
Wrong. Located on side opposite the IP..........
 

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I just got my 1981 Mercedes 300SD back after changing the a/c system from R-12 to R134a. I ordered all new parts from Performance Products, compressor, switches,dryer located behind headlight driver side, expansion valve located under dash drivers side, and provided PAG150 8oz, plus 2oz of BG fridge quite w/dye. The shop where I take my car did all the work. I was informed that they did not flush the system or replace the expansion valve. They said they did not have the right tools for the valve and that the system was clean. I had replaced all of the above 6 years ago but decided to make the switch. The problem now is that I can only get a 20 degree difference between the outside temp. and the temp. out of the vents. They got 35psi on low and 125-150 on high. Outside temp. was 77 degrees and vent temp. was at 58. Thats only 20 degrees different I excepted 30. Any suggestions would be welcome as I hate to open the system back up but that looks like that need to be done. Thanks NOTE: Just got back from a 100 mile run outside temp. was 83 degrees with vent temp. at 57 degrees. I would also add that the 2oz of BG oil was added in low side after unit was fully charged. UPDATE: I removed 6 ozs. of R-134a and the oil that came out with it and took the car on a 250 mile run, got the vent temp. down to 45 degrees, more that the 30 I was expecting. Advice, you can not use the sight glass to charge a 134a system, it is only there for R-12.
 
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