Tracing aircon leaks behind the dashboard

Discussion in 'Interior' started by br1anstorm, Aug 13, 2008.

  1. br1anstorm

    br1anstorm Active Member

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    Mar 14, 2007
    Location:
    Scotland
    Car:
    1990 Mercedes Benz 560 SEC
    The aircon system in my 1990 560 SEC has a tiny leak. A dye test confirms that it isn't anywhere in the engine bay. A sniffer test suggests the leak is somewhere in the circuits below/behind the dash panel, in the driver's side footwell (NB the left side - I have an LHD euro-spec car).

    Dismantling the dash is a daunting prospect. The leak is more likely to be at a joint - eg around the expansion valve - than in a system component. But where do the hoses run and where exactly is the valve located? Can anyone advise, or point me to good pics/diagrams, which explain what panels or fittings to remove in order to see and check the hoses and connections?

    br1anstorm
     
  2. franey

    franey Hardcore MB Enthusiast

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    Did you look at the parts epc? Several versions depending on model etc, but at least the diagrams show where the pipes terminate and you may not need dismantle the dash but access it from below if you get my drift.

    Does it get warm in Scotland?
     
  3. jaymanek

    jaymanek Authorised Forum Sponsor Authorised Forum Sponsor

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    Well i hope its not the evaporator.... very expensive and you have to strip the whole dash..
     
  4. OP
    OP
    br1anstorm

    br1anstorm Active Member

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    1990 Mercedes Benz 560 SEC
    I've looked at the parts diagrams on the Russian website (what's epc? electronic parts catalogue? I thought only dealers could access that). But those exploded diagrams don't show what else is around/above/behind the hoses or connections you're trying to reach. Ideally what I need are the sort of diagrams or pictures you find in a Haynes manual... to figure out what else I have to remove/dismantle in order to see and check the a/c circuit and connections.

    Warm weather in Scotland? You'd be surprised... if climate change goes any further, I'll be putting solar panels on the roof (of the house, that is, not the car!).

    br1anstorm
     
  5. BIG Sean

    BIG Sean Hardcore MB Enthusiast

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    Would you be able to post the link to this parts website please.

    Found it but is there a way of translating it? Can't see the parts diagrams at all!
     
    Last edited: Aug 14, 2008
  6. OP
    OP
    br1anstorm

    br1anstorm Active Member

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    Scotland
    Car:
    1990 Mercedes Benz 560 SEC
    BIG Sean - we're in danger of going off topic... but if you've found the site, there are two things to remember. If you land on what looks like a home page, you have to type in your car model or type into the box. This takes you to the relevant parts pages. Once there, if it looks like a blank page, SCROLL DOWN! The list of parts/sections, in English, will come into view.

    Here's a link to the 560 SEC parts page on the site (I hope!) http://www.detali.ru/cat/oem_mb1.asp?TP=1&F=126045&VIN=
     
  7. OP
    OP
    br1anstorm

    br1anstorm Active Member

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    Location:
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    Car:
    1990 Mercedes Benz 560 SEC
    An update on the original post which started this. The bad news is that there is a leak in my car's system. The good news is that it's at a connection to the expansion valve, and not in the evaporator.

    In case anyone else is reading this thread in search of help, the expansion valve is pretty easy to get to: just remove a couple of lower dash console panels above the footwell, and it's right there. The best illustrated guide I found - though the pics are of a W123 - is on a useful US site called dieselgiant.com. The site covers more than just diesels. Here's the link to the article and pics of the a/c overhaul.
     
  8. jaymanek

    jaymanek Authorised Forum Sponsor Authorised Forum Sponsor

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    well done... so is there a washer in there
     
  9. OP
    OP
    br1anstorm

    br1anstorm Active Member

    Messages:
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    Scotland
    Car:
    1990 Mercedes Benz 560 SEC
    A washer, Jaymanek? Are you referring to 'O' rings? The expansion valve has four pipe-connections (two in from the firewall/engine bay side, and two up into the evaporator). I haven't yet removed the valve, but I reckon each connection is sealed with an 'O' ring. They are not all the same diameter.

    I think that while I'm at it - and since I have to open up the circuit anyway to sort the leak - I'll replace both the expansion valve and the receiver/dryer. I hope the new valve comes with the necessary rings. I'm now searching for a reasonably priced parts-supplier...
     
  10. jaymanek

    jaymanek Authorised Forum Sponsor Authorised Forum Sponsor

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    you can buy the rings from any decent motor factor... I bought a box full of assorted green A/C O rings for less than a tenner..
     

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