passenger door lock - vacuum logic
 

hi folks, i have read and re-read the owner's manual but i cannot understand the symptom i am suffering: when all doors are locked and i attempt to unlock the passenger door, the vacuum resists me. i have to torque the key pretty hard and pull the handle very quickly before the vacuum relocks the door. there should be no situation where one fights against the vacuum, i think - so what gives? thanks for any tips!

what vehicle?

Perhaps you should lubricate the door lock?

Atmospheric pressure is working against you.
 

The lock is closed by vacuum and you try to unlock it. Assuming the surface area of the diaphragm is approx 3 sq in, so you have 3 * 14 = 42 lbs working against you.

All vacuum lock works on the principle of pressure pushing the diaphragm. You pull a vacuum, the diaphragm moves by atmospheric pressure to the desired position. Atmospheric pressure is 14 lb/sq in. Hope this help.

Which car is not relevant. Lubrication would not help. Go into space would help.:)

That is correct; the lock linkage should override the vacuum acuator when the door is individually and manually unlocked. Removing the interior door panel and inspecting the linkage will likely lead you to the problem.

It still would not hurt to know what Car it is.
On the older W123s there is an adjustment for the Main Vacuum Valve in the Drivers Door. There is a Metal Bracket for the adjustment.

On mine the Main Valve is White Plastic and there is no adjustment.

I though the Vacuum both pushed and pulled on the locks if you use the Pull on the Drivers Door.
It sounds to Me like part of the Vac circuit is blocked or not getting Vacuum somewhere.

What part of the problem description suggests a vacuum issue?

thanks folks. i tend to forget which forums i have which signature on... and have tried to add it here. so it's a W123 240D.

qwerty, good tip. any idea how to recognize this linkage problem? i have removed and replaced the door handle several times, perhaps i reassembled it incorrectly. the door panels are all off so i can compare one door to the other, but i haven't seen any difference.

diesel911, for that adjustment, what is it that you would want to adjust? i thought everything in the vacuum system was an on/off situation, either vacuum or ambient pressure.

It is your car so you can do whatever you want. What I am saying is that there is NOTHING wrong with the lock, pod or vacuum. When you try to unlock the car after it is locked by vacuum then you need a lot of effort to overcome atmospheric pressure.

Let me give you an example. If you have a pod on the table and you use a Mityvac to pull vacuum to lock it, then you try to unlock it by pulling on the metal rod. Let see how successful you will be with Mityvac connected and when it is not.

"to unlock the passenger door, the vacuum resists me"

When you unlock Vacuum Pulles the Lock Plunger up. When you lock Vacuum pullse the Plunger down.

If something kept one side of the Vacuum Element from getting Vacuum or venting the Element would not want to move easily.

Not when the lock is manually operated on an individual basis. In that case, the linkage should disconnect from the vacuum actuator and allow key to move the lock without vacuum influence.

Note exactly the complaint:

Vacuum is doing what vacuum is supposed to do; it's the linkage that is the problem.

I will wait and see what the Origional Poster finds is wrong.

hi folks, i agree that the vacuum and actuator are working, in the sense that they exert force. i think qwerty is correct that there is a mechanical misconfiguration between the lock and actuator. this symptom may sound natural but seriously, are you all experiencing it too? it makes me afraid i'm going to break the key off to enter the passenger door.

i will go check out the linkage in daylight, but please let me know anything in particular that i can look for. thanks!!

If there is no misconfiguration try disconnecting both Vacuum Hoses from the Actuator; this should allow the Actuator to move up and down when the Key is used with no influence from Vacuum.
See if it has an effect on the force needed to turn the Key.

Diesel911, i agree that your approach would solve the problem - at the cost of losing power locks on that door.

here is a clue from visual inspection. the driver's door has an additional little vacuum cylinder adjacent to the handle. am i simply missing this on the passenger side?

(you can see that the passenger door was a respray replacement; perhaps whomever installed it did not know about this detail.)

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