Central locking R129 makes weird sound...

[E280T]

Since a while now the Central Locking of my 300SL R129 makes a weird sound. As soon as the ignition is switched on a strange sound comes from the right rear part of the car. I checked in the trunk and it seems to be the Central Locking pump, something with a red knob that can be pushed in. Every five seconds it makes this sound. Sounds the same as when the Central Locking is activated.

Is there a simple solution for this problem, or can I - for now - deactivate the Central Locking? I prefer that over this annoying sound...

Thanks!

 

[television]

I think that you have a leak in the vacuum system and the pump is running all the time,,it will burn out if you do not find the leak,, best to just unplug the electric connector for now on the PSE pump

 

[E280T]

Aha. thanks Malcolm.

Where is the PSE pump located, in the right side of the trunk?

 

[television]

Maybe not the pump as it is under the rear seating I think and38 in the picture

Could the sound be from the fuel pumps under the rear of the off side rear wheel

 

[E280T]

It's not the fuel pump cause this sounds different. And also, when the ignition is on and I lock the doors from inside they all lock, but then along with the sound after 5 seconds, the doors open up again. Definitely the Central Locking system. So the pump is # 38 and located under the rear seating? Would think it's easier to just remove a fuse, if it doesn't interrupt with other electric groups that are running on the same fuse...?

 

[Alan Mustard]

Hi, the thing with the red knob on that can be pushed in is the vacuum cell for the petrol flap. I would cut the vacuum pipe to this and blank it off then see if the noise disappears. If it does it must be the vac cell.

You can use a piece of rubber vacuum hose to rejoin the pipes afterwards.

 

[E280T]

Hi, the thing with the red knob on that can be pushed in is the vacuum cell for the petrol flap. I would cut the vacuum pipe to this and blank it off then see if the noise disappears. If it does it must be the vac cell.

You can use a piece of rubber vacuum hose to rejoin the pipes afterwards.

Thanks! So if I cut the pipe there I should seal it airtight or can I just leave it open? The red knob sometimes also moves, or atleast when I push it in, it pushed itself out along with the 5-second-sound...

 

[television]

It is very easy to get to the PSE pump through the access panel. You must not leave a pipe open as the pump will still run. Why not get a pipe clamp to close it for now

 

[E280T]

It is very easy to get to the PSE pump through the access panel. You must not leave a pipe open as the pump will still run. Why not get a pipe clamp to close it for now

Underneath the rear seating there is an access panel to the PSE pump? then I disconnect the electric connector. Or I find the leak in the hoses...
Correct?

 

[television]

If you put a brake pipe clamp on the vacuum line to the fuel gauge,,that will work and you will still have the central lock, or you replace thew vac unit for the feul flap. Or lose all of the locking and disconnect the pump

 

[Alan Mustard]

E280T, if you cut the vac pipe near to the fuel flap cell you would need to seal airtight the side which goes to the PSE pump. It would be ok to leave the side which goes to the fuel flap cell open.

If it then works ok it must be the fuel flap vac cell. Hope this makes sense?

The PSE pump is also located in the boot on the drivers side just underneath the fuel flap vac cell.

 

[E280T]

Okay thanks. I will check it out.
For me (here in Germany) it's on the passengers side