Where is vacuum reservoir on 560SEC?

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Bill Bunn - 16 Jul 2007 21:45 GMT

I think my 86 560SEC has a vacuum leak - the idle is rough and when I turn
on the A/C, the vacuum gauge moves toward the red. A manual on cd gives me a
vacuum diagram and shows a vacuum reservoir. The removal instructions say
"Remove bulkhead on left below front fender".There is a fuzzy picture but I
cannot make out where the bulkhead is located.
Can anyone help?

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Tiger - 17 Jul 2007 03:42 GMT

No vacuum reservoir on gas engine vehicle. What you need to check is all
your vacuum hoses to make sure they are tight. Pull them out and put them
back on... on some connector, you can snip a bit off and put back on for
tighter fit.

However, I suspect you have a large vacuum leak on the large black hoses...
they are on both side of the valve cover... spray carb cleaner at the end
cap and see if it affect the engine... I am pretty sure they will.

Other source of leak is by the idle control valve... the black hose fitting
there. Spray carb cleaner whereever you suspect may leak or not... and if
engine act differently, you definitely got a leak.

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Karl - 17 Jul 2007 05:07 GMT

Yes, there most certainly is a reservoir. You need the reserve for when you are going up a hill. It
is behind the drivers inner fender. Pull the wheel and the plastic inner fender liner'
Pictured here, #5:
http://www.detali.ru/cat/oem_mb2.asp?TP=1&F=126045&M=117%2E968&GA=722%2E323350&L
=765%2E706&CT=F&cat=569&SID=80&SGR=015&SGN=01

> No vacuum reservoir on gas engine vehicle. What you need to check is all
> your vacuum hoses to make sure they are tight. Pull them out and put them
[quoted text clipped - 8 lines]
> there. Spray carb cleaner whereever you suspect may leak or not... and if
> engine act differently, you definitely got a leak.

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Tiger - 17 Jul 2007 15:56 GMT

OH! So that's what that thing is... I didn't see them on my old 380SE. I
assumed that was the yellow checkvalve's job to prevent loss of vacuum
during the time of no vacuum.

I know diesel cars has them... older one that is... so Karl, what MB has
them?

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roland franzius - 17 Jul 2007 07:56 GMT

> I think my 86 560SEC has a vacuum leak - the idle is rough and when I turn
> on the A/C, the vacuum gauge moves toward the red. A manual on cd gives me a
> vacuum diagram and shows a vacuum reservoir. The removal instructions say
> "Remove bulkhead on left below front fender".There is a fuzzy picture but I
> cannot make out where the bulkhead is located.
> Can anyone help?

The vacuum reservoir is the brake assistant at the main caliper. A/C
makes a load. The constant idling adjustment changes air flow and vacuum
in order to hold the revv.

Vacuum leaks can be heard: Mostly its the locking mechanism in the
doors. With engine off the reservoir holds for some 10 openening and
locking cycles.

Signature

Roland Franzius

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Karl - 17 Jul 2007 18:34 GMT

The 126 body does not use engine vacuum for the door locks. They have their own dedicated pump in
the trunk. #68 here:
http://www.detali.ru/cat/oem_mb2.asp?TP=1&F=126045&M=117%2E968&GA=722%2E323350&L
=765%2E706&CT=F&cat=569&SID=80&SGR=045&SGN=02

> > I think my 86 560SEC has a vacuum leak - the idle is rough and when I turn
> > on the A/C, the vacuum gauge moves toward the red. A manual on cd gives me a
[quoted text clipped - 10 lines]
> doors. With engine off the reservoir holds for some 10 openening and
> locking cycles.

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