Mercedes-Benz W123 Vacuum Door Lock System

[@mrkzj2]

Duke, thanks for this video. I've always been curious about how these old Benz vacuum systems worked and you've made it all a lot easier to understand.

[@rogeliorivera5858]

thanks for helping us , thanks to you and to your efficient videographer ...

[@jt7839]

Thanks Duke, this really helped me out.

[@chinitaduke]

Tomax, Thanks for your response, your positive input, and looking forward to seeing your clip. Please let me know when you post your video(s).

[@DeTODOunPOCO-uv8mb]

Master, I look years for a good video, really man you need make more videos like that

[@budgetcarsforsale2637]

A nice relaxed informative explanation. Good job also by the videographer.

[@firfyter]

It is a vacuum system so you should be drawing a vacuum on the actuator to test it instead of blowing into the opposite vacuum fitting. Nice video. You seem to have a good idea of how to fix it except that there is no pressure being pumped but instead it is a vacuum.

[@iancaseley705]

Thank you for this very helpful video. But it's a vacuum system and you are applying pressure to the opposite side of the diaphragm when it's a vacuum that's used. Referring to both vacuum and pressure is confusing. But it's a great video and thanks for going to the trouble of doing it.

[@kuldipdhak7972]

Good experience man thanks I have 1985 300d turbo always low vacuum alarm

[@timickan]

Nice video, thanks for taking the time to make it.

[@Aaronhouston33]

the one reservoir tank in the diagram was for the EURO headlamp leveling switch that was not included on the USA models.

[@unimogman404]

Excellent video, very informative. I '' Krown '' to have my W123 under sprayed and after, could not shut off the engine nor lock or unlock the doors. Is it possible that, if the hit a vacuum hose that is hooked to a door actuator, the other doors and the engine shut off would not work ? Thanks, your help would be appreciated. André , Canada , 1985 300D , 366,000 km.

[@w00f72]

This dude kicks ass

[@HHSGrad65]

Thanks You helped me see the problem now I can fix it!

[@richardengstrom4758]

I have a 1983 300 td (wagon) my door lock actuator rod coming down from the button to the vacuum motor has a centering spring, all of mine on the car are broken, i need 6 springs but cant find a source, any fixes you know of or a place to find the tension springs? Rich

[@maksym71240]

Great video, Thank you!))

[@technicalitems731]

Where can we buy colored vacuum line? I’d like to put it back with proper colors. I’d hate to have to spray paint a bunch of lines.... - where to buy door lock actuators? Door latch actuators? Thanks

[@trevno]

Great Video!

[@LesterLovesWatches]

Can you please provide a scan or link to that useful diagram?

[@kermitefrog64]

Question, Is there a vacuum actuator that unlocks the trunk? Where would the button be that pops the trunk on the 1981 240d?

[@jonfrazier7827]

Hi looking for a schematic for the seat belt buzzer relay for w126 1981 300sd. The connection harness broke and wires just hang. Thanx

[@twdarcy]

I have a complete mess in mine. I disconnected the door lock vacuum line in the engine compartment, but the front passenger lock stays locked with vacuum. lol

[@ahmedrmy2404]

my dear Duke my mercedes is shaking very strong when i put the speed on D and i take the break at the same time . can you help me please ?

[@stevebutler4364]

Thanks Duke!

[@chathuran]

Dear Duke, What are the complete part list to buy if my Mercedes Benz W123 car Need the Vacuum Door Lock system. Can I get the part lists ?

[@brianlaugharne3302]

It is not pressure that operates the system ?? it is vacuum (suction) that operates the actuators pressure (blows) If you note none of the rubber manifolds for the nylon tubes are clipped because it is vacuum operated if pressure was used it would blow the unclipped hoses out of the rubber manifolds!!! Just thought it was worth mentioning

[@bobvansand6346]

Nice done! Thx bro

[@rizalsaiful6058]

How to.take out actuator of gasoline lock W124?

[@FoxJacker]

Great video! :D

[@Aaronhouston33]

the engineering of the W123 is extraterrestrial space ship technology, no has everer existed like the w123 where you do not have to any thing to it for the first 250,000 miles

[@AtkozoKoppany]

Dear Duke, My Mercedes Vaneo's Central locking system plays up by locking-unlocking the doors while driving the vehicle.Please help solve the problem.

[@dukecallaway7992]

I would check your vacuum lines that fill the air reservoir (yellow with grey stripe) and to the interior (solid yellow) to make sure that they are connected to a y-rubber hose and that the (2) two-way vacuum check valves are not leaking. The valve should allow air to pass through on one side if you blow through it while restricting air when you blow through the opposite nipple. The location of these parts are near the brake power booster on the driver's-side engine compartment.

[@jempoof]

Best way to find which door is leaking is feed the input hose with a smoke machine.

[@TWINNIdk]

Very Nice

[@danielgriffin8132]

To create a locking system like this is insane ridiculous making a nightmare for car owners.

[@kuldipdhak7972]

Your camera is not focused

[@usrock1]

Bad engineering , I've never understood the purpose of it. I have 78 240D manual I have a problem with all the doors and the driver back door could not be opened..

[@technicalitems731]

usrock1 wish someone would come up with 12v retrofit parts!

[@darksidehero]

why is it called a vacuum system when it's actually a pneumatic system?

[@dukecallaway7992]

Since both systems are powered by air, vacuum was probably easier to remember and for language translation. Great question

[@joellindell7930]

Duke Callaway its a vaccum system.. not copressed air..

[@firfyter]

Darkside Hero it is a vacuum system. In the video he blows into the actuator and it moves but what actually happens is the system pulls vacuum on the opposite side that is demonstrated here in the video. So when he says, "this side is the unlock and this is the lock". It is actually reverse of what he says because he is blowing when he should be drawing a vacuum.

[@darksidehero]

Firfyter Thanks for the explanation .

[@StonemanRocks]

i hate all this over engineered crap on mercedes electrical problems up the ass on older ones

[@usrock1]

Very bad engineering never understood the purposes of it , there is no need for all that mess. The car works fine without it I have 78 240D the back driver door would not open I think is the vacuum line is the issue; one of the reason why I am selling it.