[W126 Coupe] Vaccum Leaks

[dick.spellman@gmail.com]

Vacuum line sold by the meter or yard at MB dealer.  Color code not important and not easily matched.

Fun when everything works after a bit of digging.
A mechanic would have charged a lot of labor hours hunting down that type of gremlin
Dick Spellman


----- Reply message -----
From: "L&D gardner" <cruftsk9 at tpg.com.au>
To: <mbcoupes at mbcoupes.com>
Subject: [W126 Coupe] Vaccum Leaks
Date: Thu, Nov 24, 2011 12:07 am


Hi Dick
   Many thanks, you were spot on,I removed the vacuum pods and they seemed 
to
hold vacuum reasonable well and also when connected ,one thing I did find 
was some dodgy after market wiring was stuck inside the flap door.

It turned out to be the maroon and yellow striped
line to the headlamps it had chaffed through going under the idle control 
computer and was losing a lot of vacuum. I am really pleased to have finally 
found the cause,now I have just got the track down some new vac line

Many thanks to Dick and all the people who freely gave advise.

                                                                Kind Regards 
Dan Gardner  1986 560  SEC Euro (220kw)




Message: 1
Date: Tue, 22 Nov 2011 12:49:12 -0500
From: Dick Spellman <dick.spellman at gmail.com>
Subject: Re: [W126 Coupe] Fw: Re:Vacuum Locking
To: Mercedes Coupes Mailing Lists <coupes at mbcoupes.com>
Message-ID: <4ECBE098.5000000 at gmail.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

Dan,

Check the vacuum line to the IC economy gauge, the headlamp elevation
switch itself as it does provide a controlled vacuum leak, and the
vacuum circuit from the euro headlamp elevation switch to each of the
headlamp feeds.  Then test each feed coming off of the vacuum switching
valve (remove one at a time and follow the lead to each pod to see each
pod actuator move and HOLD position under 12-15 hg) to the air control
flap pods for the automatic climate control.  The main cabin air door
has two pods each with dual elements and they act in tandem.  So you
need to test both vac lines at once to achieve door operation.   My
guess is that you have one or more leaking vacuum pods that regulate air
flow to the automatic climate control.  It is certainly possible that a
leak might exist in one of the two lines to the headlamp vacuum
elements.  Mighty vac each line to determine the whereabouts of one or
more leaks.

The other main vacuum feeds go to emission components and can be
isolated in the engine compartment and tested.  There is one line to the
transmission vacuum modulator.  When this breaks, you get a hard shift
in all gears.  Other known issues relate to the air slider valve hoses
and various connections and rubber joints on the intake itself.

The foam on the expansion valve that has disintegrated can be replaced
using any tight cell foam (like a bedroll cut up from an army/navy
store) tie wrapped in place.  It's just there to prevent warm moist air
from coming in contact with that area when icy cold.  The resultant
condensation will cause a drip and mold etc..

I'd replace the vacuum rubber connectors with more of the same from MB
if available.

Good luck,

Dick


>

>

>                                                                Kind

> Regards

>

>                                      Dan Gardner  1986 560  SEC Euro

> (220kw) 


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