Speaking of the vacuum locking system

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

Reply to
Ken
Loading thread data ...

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.

formatting link
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.

Reply to
trader4

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

Reply to
Ken

formatting link
their sales catalogs usually have excellent vacuum diagrams.

like these scans:

formatting link

Ken wrote:

Reply to
Darrell with DieselBenz.info

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.

Reply to
Hazey

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

Reply to
Ken

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.