R129 SL Repair, Restoration and Fitting service

[r129co]

Hi there, my SL parts company R129 Co are now offering interior repairs, electrical and engine diagnostics and repairs, and parts fitting, from here in our premises in Kent, 25 miles off the M25.

We've been working with the R129 SL and W140 S Class for over a decade and are confident we can cover all major problems, such as central locking pump repairs, soft top roof operation issues and warning lights diagnostics/fixes.

More info on our website at https://r129.co/repairs-detailing-restoration

Happy to answer any questions here of course.

Cheers
Carl, R129 Co

 

[LostKiwi]

Hi and welcome.

Here's a puzzler for you.
My r129 central locking pump died (water damage). Up until it died the central locking worked perfectly.
I changed the pump and now the doors won't unlock. The boot, fuel flap, cubby boxes and glove box all work fine. Swapping the lines around makes no difference (and the boot - which works - is on the same line as the doors anyway). I'm almost certain it's not the door actuators (2 failed at exactly the same time?) and there are no vacuum leaks.

 

[brianbrian]

Was it a new pump you fitted?

 

[LostKiwi]

Was it a new pump you fitted?

Can't get new.

 

[brianbrian]

Oh, can you not borrow a known working one. As the one you fitted may be faulty.

 

[LostKiwi]

Oh, can you not borrow a known working one. As the one you fitted may be faulty.

But if it was faulty the boot wouldn't unlock (on the same pressure/vacuum feed)?

 

[brianbrian]

Have you tried by opening and locking each side with the key to see if the actuators are working.

 

[LostKiwi]

Have you tried by opening and locking each side with the key to see if the actuators are working.

Been using the key ever since this first appeared as an issue (about 2 years ago - cars a bit of a barn queen and only comes out a few times a year...

 

[brianbrian]

Our 129 only does about 100 mp year, as our driving days are nearly over. Sorry what I meant was, when you put the key either side to lock or unlock car ,does the opposite side operate? Or do you have to lock and unlock each door.

 

[brianbrian]

Have you taken the door card of?

 

[LostKiwi]

Have you taken the door card of?

Lock and unlock each door manually.
Both door cards have been off. No issues with the pipework.

 

[brianbrian]

The actuator has a small plug with 3 wires, are they getting a feed.

 

[LostKiwi]

As far as I can recall there are no wires to my actuators but I can't check as the car is 500 miles away.

 

[brianbrian]

Yes, They are not just vacumm operated.

 

[LostKiwi]

Yes, They are not just vacumm operated.

Ah ok. Been checking this by looking at parts and diagrams.
It appears there are two types of actuator. One has a pair of contacts to record the position of the actuator and one doesn't. Not sure which mine is (it's on the cusp of the changeover so will have to check however I do know that it does know if the lock is open or closed as you can see it on the LEDs when you lock the car with the key. If one door is unlocked still the LED keeps flashing till the opposite door is locked (and vice versa unlocking) so I think it's fair to assume it has switches and that they work.

 

[brianbrian]

The three wires in the plug that goes into the actuator, two off these go to the supply pump.

 

[LostKiwi]

The pump runs fine and unlocks everything except the doors. There are three lines out of the pump which then go into a pair of manifolds on top of the pump. One manifold splits to each door and the boot . The other splits for cubby boxes, glovebox etc and the final output of the pump passes through to the fuel flap. Since the boot lock operates it means pressure/vacuum is getting to the manifold. Swapping the door line to the fuel flap makes no difference and the fuel flap still operates.

 

[brianbrian]

I think your problem is the actuator, the electrical valve is not working in the actuator so will not allow vacumm in.

 

[LostKiwi]

I think your problem is the actuator, the electrical valve is not working in the actuator so will not allow vacumm in.

Both actuators at once?

 

[brianbrian]

If one actuator stops working, then you have to lock and unlock each door with the key. Find out which one is not working.