Speaking of the vacuum locking system

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Ken - 10 May 2006 20:27 GMT

Bringing my 73 SL back to life after it's been a-sittin' in the garage
for 7 years. Already have had the engine gone thru $$$$ (both heads had
pretty much rotted out and needed finding some good used one which
wasn't easy), sealed up the transmission leaks, and I've replaced most
everything in the front suspension$$, still need a new soft top$..BUT
the v-lock system isn't working

Pulled both door panels, checked all the other vacuum units for leaks,
and still nothing, may have hooked something up incorectly..so where
can I find a diagram of the vacuum lock system? There's nothing in the
phone-book sized manual at all

Ken

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trader4@optonline.net - 11 May 2006 11:57 GMT

Are you sure it's not there? In my 116 manual there isn't a lot of
info, but after all these years, I finally stumbled across one diagram
that shows it all, though it's not easy to read. It was in the
section talking about the central locking system.

I also saw a guy on Ebay recently that was selling vacuum repair guides
for some models. Just looked and he doesn;t have one currently listed
for yours, but you could email him and see what he does have.

http://cgi.ebay.com/ebaymotors/VACUUM-SOURCE-TROUBLESHOOTING-FOR-MERCEDES-123-12
6_W0QQcmdZViewItemQQcategoryZ34227QQitemZ8063331528QQrdZ1QQsspagenameZWDVW

If that doesn't work, search on mercedes vacuum troubleshooting on
Ebay.

If you have the door panels off it should be easy to diagnose at least
the first part. I'm not familiar with that model, but just fixed my
116 80 300SD. I suspect it probably works similar. There is a vacuum
line that runs from the main vac line in the engine bay, through a
check valve located high up under drivers side dash and on to the
"vacuum switch" located in the driver door. The switch is a little
device with a plunger on it that gets moved by the key turning.
Center line is connected per above to engine vac source and reservoir.
The other two lines from the switch go to the locking vacuum elements
for the other doors, trunk, gas lid, etc. The vacuum switch applying
vac to one line opens, applying vac to other closes them.

With a vacuum tester that you can find at parts stores or Ebay, you can
generate and measure vac and figure out what's going wrong. If you
need a new component, look on Ebay. First thing to check is if vac is
present at that center hose on vac switch. It should also hold this
vac for days, so doors can be opened. I'd check where the vac lines go
through the firewall. Both of the ones I've had fail went right at
that point. Just pulling on them, while looking for the leak, they
broke off.

There are guys selling new replacement vac elements etc for a lot less
than u can find them for elsewhere.

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Ken - 11 May 2006 16:10 GMT

Thanks for the info and reply..especially about the key operated
"vacuum switch" in the driver's door...have two extra ones obtained
over the years from wrecking yards and never figured out what was what
on 'em

I'll go thru the manual page by page later today. And if necessary,
draw up flow chart and go from thar

Even had trouble with the key operated door latch mechanism, added a
shim to the device and they're both back in shape now

Sure have missed driving the SL, but that was back when gas was a buck
a gallon...Ken

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Darrell with DieselBenz.info - 12 May 2006 14:06 GMT

http://www.performanceproducts.com

their sales catalogs usually have excellent vacuum diagrams.

like these scans:

http://www.dieselbenz.info/images/vacuum_engine_pp.jpg

>Bringing my 73 SL back to life after it's been a-sittin' in the garage
>for 7 years. Already have had the engine gone thru $$$$ (both heads had
[quoted text clipped - 11 lines]
>
>

Signature

thanks,
Darrell

http://www.dieselbenz.info/

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Hazey - 12 May 2006 19:44 GMT

Don't forget the trunk and the fuel door. The trunk unit goes bad on
the '72 sedans pretty often. You will definitely need a vacuum sensor,
and be gentle with that old hose. It gets very brittle with age. Best
of luck.

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Ken - 12 May 2006 22:58 GMT

Thanks
Already checked both the trunk n fool door for leaks and proper
operation with a Mighty-Vac, (along with that sneaky one they located
behind the inst panel)

After having this same car for 30 years, there's not much I haven't
taken apart on it at one time or 'nuther

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