Door lock question - PeachParts Mercedes-Benz Forum

Bigmon · #1 09-08-2003, 08:20 PM

I have a 92 300E with 166k. Recently, when I lock the drivers door the other doors don't always lock. After 4-5 attempts they lock.

Any ideas?

MALK · #2 09-09-2003, 12:02 AM

vacuum leak?

speedy300Dturbo · #3 09-09-2003, 10:10 AM

What you need to look at are the wires in the driver's door that make contact when the key is turned. They can get brittle and frayed over time.

Try locking from the trunk and passenger's door. If it works fine, then you don't have a vacuum leak and have narrowed your problem down to the driver's door. Vacuum leaks are not very common in 124's, at least MUCH less so compared to 123's!

haasman · #4 09-09-2003, 12:33 PM

Bigmon

It means that your lock cylinder in the driver's door is starting to go. It has a U-shaped connector that is at the end of the lock cylinder assembly which is inserted into the door. The U shaped end allows a slight swivel when turning the key. The end of the U shaped piece inserts into the actual door lock mechanism and does the physical locking and unlocking, including operating the vacuum lock/unlock system.

As a side note, the lock cylinder also has a three wire connector that enables/disables the alarm system.

When one side of the U breaks often while the other side continues to stay connected you get this "slowed respones" to the turning of the key. What happens is the twisting (torque really) from the key use makes the U part fail.

The bad news is about $350 for a new lock cylinder with a key cut to your chassis #. Additional bad news is that the broken U-shaped piece is not avaiable separately and the claim that it cannot be repaired.

Across several weekends I have explored and researched the above with regard to the 190e which, BTW had the same symptoms and problems.

The good news is I repaired the lock cylinder U-shaped connector.

Haasman

Bigmon · #5 09-09-2003, 05:29 PM

I tried locking and unlocking on the passenger door and everything works great so it looks like my problem is in the drivers door. I have noticed a slow response too on the drivers door when it works.

Thanks for the help.

haasman · #6 09-09-2003, 05:46 PM

My guess is the slow response is from one or two areas- The vacuum pump/vacuum lines have a problem and/or the lock cylinder as mentioned above.

PLEASE dont twist the key in the lock hard or you will break the remaining portions of the U-shaped connector.

Feel free to email me if you have any questions.

Haasman

Bigmon · #7 09-09-2003, 08:55 PM

So far today it's worked every time. I'm gentle with it.

If it acts up I'll just use the passenger door.

Thanks for the help.

renyf1 · #8 09-10-2003, 07:53 PM

i had a similar problem and drove nuts!

for me it was the accuator ($40)...its basically the part that connects the door knob to the vaccuum pump this was getting brittle and actually broke off

the doors can be locked and everything but only the driver's side door

the passenger side door worked fine as normal

good luck

reny

djankov · #9 09-10-2003, 08:57 PM

If you still have a problem, check out my problem W124 Central Lock Puzzle regarding a similar issue. What I found out later with the W124 was the A/C water drain hoses (one on each side) of the passenger compartment will disintegrate on an older vehicle(1987) and water will flow into the floor panels and run down the wiring harness. In my case, this caused the X48F connector to corrode and only one actuator had enough current to operate. Just a thought!

1987 300D 185Km
2001 CLK 430 Convertible 27Km

MARIO FARIAS · #10 09-12-2003, 07:10 AM

pLEASE Renif, tell us more about this actuator $40.

Do you have some pictures?.

Can you buy it as an only part?

Thanks

Mario Farias

djankov · #11 09-12-2003, 08:41 PM

These actuators are electro-pneumatic. Each one is about $40. There are three (Left Door, Right Door, Trunk).

1987 300D 185Km
2001 CLK 430 Convertible 27Km

ESVIC · #12 09-13-2003, 03:09 AM

Quote:

Originally posted by Bigmon
So far today it's worked every time. I'm gentle with it.

If it acts up I'll just use the passenger door.

Thanks for the help.

This might sound to simple...

Can you just switch the U-Lock from the Passenger side to the Driver side. Personally, I hardly use the passenger side to lock the car..

toknow · #13 09-13-2003, 12:19 PM

The actuator might be the problem,
it is the one who gives electrical signal to run the pump (either vacuum or pressure) to close or open all the doors..if signal OK, the pump will start working->if there is a leak - which is also could be from the inside of the actuator - the pump will run longer anfd there will be delay in locking or unlocking all the doors.
the actuator about $49 or so, it is sealed as a vacuum unit and it has an internal electric switch...it can leak and the switch can also fail sometimes...
Hope this will help

renyf1 · #14 09-14-2003, 04:32 AM

sorry for the delay....

on my car the actuator actually had a crack....then it completely broke free from the rod connecting to the door knob

once my mech changed the acuator, everything went back to normal

for awhile though....i was able to lock and open the other doors via the driver's side door knob....that lasted like 3months

ren