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1978 450 SEL... power locks?

Started by skatinblind815, 26 July 2010, 10:48 PM

TJ 450

There should be a key sticking out of the lock/handle that engages with the door latch mechanism... the best thing to do would be to remove the handle from the outside (two 5mm allen bolts, under a plastic cap).

If you can, take a photo of it, and I'll be able to tell you is anything is missing. Alternatively, I'll see if I can find a W126 one tomorrow, as they are quite similar, and take a photo of that.

Tim
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

skatinblind815

Dudes,
I finally got to taking my door handle off and comparing it to another 116 handle that I found. What I was missing was the long shaft piece that goes from the lock tumbler part to the door latch mechanism part, because it somehow got snapped off...weird Iknow. So I'm in the process of fixing it now. But this leads me to another question of the day. Another guy on a website suggested this, but could it be that my broken lock is somehow affecting the lock vaccuum system which is then affecting the engine vaccuum system which is then causing my UNUSUALLY high idle? She idles at like 1200rpm when in park. Are these thing related or am I just crazy?
-nick

TJ 450

Nice work. Indeed, I forgot to take the pic.

There's an easy way to check if the locking system is affecting the idle speed... you can temporarily plug it off in the engine bay, and see what happens.

At the back of the engine is one vacuum line that supplies all the interior appointments (and the heater system) with vacuum. This branches off from the one in a "tree" that's located next to the fuse box (on RHD cars)... I'm not sure about LHD, but it should be there somewhere.

Just remove the gray(?) line, at the tree and plug it off with something like a golf tee.

If this doesn't work, the leak may be elsewhere... it's always a mission trying to find vacuum leaks.

Good luck,
Tim

PS, is the 1200rpm idle speed present when the car has warmed up... it should be 750-900 rpm when fully warmed up, in park. 1200-1500 is probably about right at a cold start.

Tim
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

skatinblind815

Alright man! Thanks, that reply was right on the money. That is a good place to look, I already found a couple small ones. But the good part is this engine was definitly rebuilt recently :). One other question, what do you guys think about running on a higher octane gas? There is the normal stuff, and the premium 92 octane..Any advice?

Hemersam

The vac. door locks on my '78 280SE haven't worked since I bought the car three years ago. However, since only rarely does someone else ride with me, I simple plugged up the appropriate vac. lines and use the ignition key in the drivers' door. This "approach" gets me in and out of my car without any problem---sure beats having to track down leaks, etc., then even more time fixing whatever isn't working right.
Hemersam

Karu


skatinblind815, I am only new to the 450, but I remember reading somewhere here that they should only use premium unleaded. 

flutes

Definitely premium.  98 RON if possible.  Plenty written on the topic in the forums, search for more info: the summary is your mileage will improve usually enough to offset the extra cost, and you will notice more power.
Matt
1977 450SEL

skatinblind815

Awesome. I got a tank of the premiums and I'm in the process of my cars first road trip since I got it. I also put a bottle of "Seafoam" fuel treatment in the tank and it seems to be working. The premium gas is definitly giving more power which is awesome.

Rodger

I have the same problem, doors will not lock.
I found a temporary solution.

Before trying this roll down the driver's window so you can get in if it does not work.

1. Turn the car of and get out.
2. Open the rear driver's side door.
3. Close the driver's door
4. reach in from the back door and use the button on driver's door to lock all the doors.
5. Close the driver's door.
6. I could not unlock the driver's door.  This made me nervous.  It is why you should roll down the window first.
7. Unlock the front passenger door.
8, reach in and unlock the driver's door.

-Rodger

floyd111

Shoot me, but I am having visions of Mr Bean, reading this..  ;D

Rodger

I teach 7th grade science all day.
It gets to be a habit.

Rodger

rumb

clear as mud...

Try all the advice given in 2010 and see that helps diagnose your problem.
'68 250S
'77 6.9 Euro
'91 300SE,
'98 SL500
'14 CLS550,
'16 AMG GTS
'21 E450 Cabrio

Casey

Today I got into a 1979 300SD, and locked the door with a key.  To my amazement all of the other doors quickly locked.  I checked the trunk.  Locked.  I checked the gas cap - not locked because the pin was bent to hell, but it did extend and would have locked if not damaged.  Color me impressed.  Went back to driver door a few hours later and unlocked it.  To my greater amazement, all the doors and trunk quickly unlocked.  WOW!  In owning about 15 classic Mercedes, that is the first time I have ever seen the lock system actually work as it should.  There are almost ALWAYS vacuum leaks and broken actuators, etc.  The more amazing part about this is that the car is otherwise rubbish, with so many big problems needing dealt with.  The loosest steering I have ever experienced accompanied by a fierce rattling from the steering coupler that has NO rubber left at all, water pouring into the driver footwell when it rains, a driver mirror that requires rolling down the window to adjust, rust, electrical issues, badly peeling clear coat, etc.  But hey, the locks work GREAT!