'82 300SD vacuum door lock install question - PeachParts Mercedes-Benz Forum

ecoshadow · #1 11-07-2005, 01:03 PM

I am replacing the vacuum door lock elements in my '82 300SD. The elements that the dealer sold me for the doors have raised some questions in my mind that the dealer was too busy to discuss. I am concerned because the plunger on the right front pax door replacement part seems to actuate easily with suction or pressure (as I would expect), but the two elements scheduled to go into the back doors do not. The dealer says they are in the install position. Why will they work once I install them? Also the driver's door (all electric) element does not plunge either but I figured that it may need electricity to allow movement (I hope). Can anyone shed light into my sceptical darkness?

D.Blake · #2 11-07-2005, 01:30 PM

ecoshadow,
The door locking mechanism for the 126 evolved from 81 through 85. The 81-83 the drivers door was the master lock command. No other locks would activate the automatic system. For these years, the drivers door is mechanical only, but also has a switch which activates the pump in the trunk. The mechanism for the drivers door has no vacuum/pressure diaphram or electric solenoid set up. The reason it may not lock is that the door must be closed in order to lock it. This is force you to use the key to lock the door (so you don't lock your keys in the car - but it can be done as my son has proven). Not being installed yet, the latch may be set for the door open. The rear door mechanisms are vacuum/pressure actuators only and and work the same as your front passenger door. When I have replaced these things they are a little stiff when trying to operate them before installation. I wouldn't worry until they don't work once installed. Hope this helps

ecoshadow · #3 11-07-2005, 04:21 PM

Thanks D for the info. It still seems a little unsettling to me that the back door locks are not functioning when connected to vacuum/suction but the right front door lock does function easily. The all electric driver's door lock I can believe must wait for install. Also the rt front door lock is different than the back doors, but I suppose it fits into a different space.