[R129 SL] MB Air Conditioners Problems

[Jan Kuylaars]

Hey Peter.

When you want to change the AC system from R12 into R134 you have more to
change then only the evaporator.
So you must change all rubber rings,washers and rubber pipes, because R134
is eating the old ones.
Then you must change the inlet gauge, because R134 has a different connector
to fill.
With R12 they are using Aluminum pipes and connectors on the rubber pipes,
with R134 they are using yellow cupper.

If I was looking good in the MB USA DVD , you can only leave the radiator,
the evaporator itself, the drier and maybe the aluminum pipes.
For sure that the compressor must be changed or dissembled and rebuild with
other out en inlets and rubbers.
Also the oil inside the compressor is different, so you are cheaper to
replace it.

So the costs are so high it isn't worth the investment.
We go to Belgium to let it fill with R 12, like you said there is enough
what is coming out off old business refrigeration systems.

I build the air co system into my Mazda 929 coupe myself.
Changing the evaporator is 30 minutes of labor.
That's because at that time only a few people bought the car with AC.
So the dealer could build in the system herself.

But the drain by Mazda is better done then Mercedes, I believe that's also a
reason of damaging the evaporator. Always moister on it.

Sleep well on the other side of the world.

Greetings Jan.
  -----Oorspronkelijk bericht-----
  Van: r129list-bounces at mbcoupes.com
[mailto:r129list-bounces at mbcoupes.com]Namens Peter Shelton
  Verzonden: dinsdag 26 juni 2007 2:00
  Aan: SL Mailing List
  Onderwerp: Re: [R129 SL] MB Air Conditioners Problems


  Hi Rudy,
  I am in total agreement with your comments.  There are also problems with
R 134A and other 'so called friendly' refrigeration gasses.  I still top up
R12 and R22 in many of the existing systems I am involved with as at the
moment, you can continue using them in existing systems - remember LOTS of
the recovered R12 and R22 is sitting around in containers and there is
minimal chance of easily and cheaply getting rid of this gas!.

   [On another note, Halon 1200 and 1301 is still used in aircraft as the
best and most favoured fire suppressant, ( is not a de-oxygenator) and so
this is still being manufactured by some countries.]

  The car air con system should be totally cleaned, checked with nitrogen,
new evaporator fitted, when changing from R12 to R134A.  This is not often
done (cost? or lack of knowledge), but the cost catches up eventually!.

  I still believe that in about 1920, a few 'Heating Engineers' had a spare
heater lying around, and were deciding what to do with it!   The outcome was
they totally enclosed a Mercedes Benz Car around it!  There is still
difficulty in servicing heaters (in many cars) but the MB is one of the most
challenging to repair in this area.!  You are right that the R129 and W 140
is a challenge but there are many other models that are still time consuming
to remedy.

  Have a great day - sunny here in the Manawatu in New Zealand! (But about
42 degrees F).

  Regards, Peter S.


    ----- Original Message -----
    From: Flodur2 at aol.com
    To: r129list at mbcoupes.com
    Sent: Tuesday, June 26, 2007 11:23 AM
    Subject: [R129 SL] MB Air Conditioners Problems


    It is a well known that MB air conditioners are poor from a design or
manufacture standpoint in that they prematurely fail prematurely due to
leakage at joints, especially in the evaporator, the heat exchanger inside
the cockpit. Although the part is only a couple of hundred dollars,
installation is a pain (a lot of work in an awkward position) in the W140
and R129 series models because so much work is required to get at them.
Failure often occurs between 5 and 10 years. There are no moving parts in
the evaporator and it is protected from the outside environment but fails
frequently nevertheless. MB acknowledges no responsibility for this part.
Repairs have cost many owners dearly. I speak from experience. Maybe MB
hasn't adequately factored in the materials corrosion requirement of the
R134a refrigerant, versus the now banned R12 (Freon).

    Rudy





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