R129 Central locking pump

ROLLERMANZ

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hi Guys,

I need abit of help please,

I have a mercedes sl r129 1991.

The central locking pump motor has been replaced.. the pump starts and it does locks the car but unfortunately not unlocking the car

Any help would be appreciated please
Thank you
 

television

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If the pump does run, then could be a diaphragm split in one direction in a lock
 

LostKiwi

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Did it do this before the pump was replaced?
 

Richard Moakes

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Need to be more specific, does it unlock anything? Or no reaction from the pump?
....and as per previous poster, why was the pump changed and did it work before the change?
 
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Here is everything I know as I had a problem with mine, iirc... with a cheap fix bomb shell for burnt out motors at the bottom of the page!

The pump blows to open & vacuum to lock.

It appears that under vacuum the electric motor struggles more than when blowing, so to mitigate this the car helps out with a vacuum line that goes to the intake manifold M103, must be similar on other engines. The line is grey/transparent on my car. When entering the engine bulkhead area this line goes into a block with many vacuum lines of all colours coming off it. Mine had a small split in the black plastic block, after roughing the surface I sealed it with "Mr Dental" denture repair acrylic that you can buy from a company called Bracon Dental. This split was causing a lost of pressure and you don't want that.

The vacuum/pressure lines in the boot are yellow with the exception of the grey vac helper line coming up from the engine and the black line going to the fuel release actuator.

Get an electric tyre pump from Halfords, cut the end off and you can blow down each yellow line in order to at least check that you can blow every individual actuator open. You can blow or suck them with your mouth if you can reach.

Blowing down each line individually show me that one of my vac pipes had a hole somewhere. Fortunately I found it quickly. The line had chaffed on the battery terminal and had cut it. Easy fix with a bit of clear pipe usually used for wiper jets.

My main problem was a part melted 540 type motor because it had been running all the time due to the holes in the lines. Ok... here's what I found... just remove the old 540 from the housing along with its rotary pump driver, throw that in the bin, *get an A Class vacuum pump off of eBay for £16ish along with its rotary pump and swap it over*. I installed the new pump outside of the old case on a longer bit of hose and wire because the angle of the new A Class pump outlet is at a slightly different angle than that of the SL. I think it could be modified but keeping the motor out of the case will help it keep cooler long term. Just make sure that you get the wires round the right way so blow opens and vacuum locks.

I think that's all I know.
 
OP
R

ROLLERMANZ

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Hi Guys,

Sorry been away for sometime.. i just recently checked all the hose lines and few of them were cracked so replaced them and all working now.. thanks alot for your help guys..

The only issue i have right now is the remote fobs not working. I have replaced the batteries and refreshed the solder joints on the fobs and the fobs are giving ir sensors through phone camera.. do you think i need to take the small black box out from the boot and refresh its solder joints as well?

Thanks for the help
 

LostKiwi

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Have you resynced the IR fob?
 
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