DM914

My pump is running longer than normal want to check - want to check the pressure tank - any idea of where it's located? I can her something behind the rear driver seat above the storage box. I'll pull the pump out of the car to get MB part number - motor sound like it running - but cnetral locking not working.

Is their a sticky some where in the forum on the trouble shooting guide and procedures to the central locking - I've found a few Utube video talking about the pump repair - and I've seen a hard copy of a locking repair manual ( but it's $ 200 USD ) which sounds crazy expensive.. wanted to knwo where to hook up bench power and which pins to test the various ports for pressure and vaccum function..

Pazo

There is a vacuum tank in trunk near the radio antenna, behind trim. Another is near the driver side front wheel, behind Sacco-board with vent. A very common leak is in the firewall vacuum distributor - see attached photo where it is detached and fixed with epoxy glue. The distributor is adjacent to passenger side strut tower.

Good luck!

DM914

Thanks much - I have bought a new distribution block - I will dig an look for the wtwo other spots -

dumb question is their a correct way to remove the vaccum fittings ? I don't just want to grab and pull - special tool are trick to remove them ?

Pazo

Your question is not dumb. Recommended tool is an open-end spanner. 7mm IIRC.
These sites may give you clues (use search - there are many good threads about the PSE pump):
STAR TekInfo

DM914

I also looked in trunk near the antenna ( drivers side rear trunk ) I removed the lining and there is no tank located that I can see - not the easies spot to crawl into to look but with a flashlight I see nothing but the power antenna assembly and my radio tumer/amp that may or may not be functional ( that's another story )

woudl access to the storage tank be by removing the inner panel above the storage box inside the car or maybe via the soft top storage area - how big is this thing what am I looking ?

when I try to lock the drivers door it like you can hear something trying to run behind the lock mechanism in the car ( not the door )

Pazo

The trunk tank is for multiple contour (orthopedic) seats. So if you do not have that option, there will be no tank either. The other tank in left fender is for HVAC. I should have mentioned those "prerequisites". A hand vacuum pump is very useful, costs maybe $50-80. Test each line from the PSE pump for leaks.

DM914

Thanks much - I don't have the ortho seats - I have a hand vacuum pump ( for brake bleeding ) with a gauge. so will pop each line and see if I can "predetermine" it's not leaking.. the main yellow line out of the pump must go to the front HVAC tank - I do have a new front distribution block which I may change just because...

thanks much ..

I'll post some info on what I find once I start ripping into it..

DM914

When you say left fender - for North American Car - woudl that be drivers or passengers fender ? what does it look like too ? how big ? Any pictures of it in the car so I know what I'm looking for. I would think it's near the distribution block under the cover on the passenger side ( where MAS and overload protection relay is etc )

Pazo

It is item 122 in attached picture (Heating/Air-conditioner vacuum parts). Driver side. Hope this addresses your question...

DM914

How do you access the pressure tank # 122 - I've replaced the distribution block ( had a small crack like all the others ). which line runs to the tank from the front distribution block ( I can pressure test the tank through the line from the block )

My heater controls ( flaps etc are functioning ) so my guess is the front tank is OK - but I have an issue with a component in the locking system - an actuator or a line - those would be easiest to text from the pump end -

My pump ( 1992 SL500 ) looks to encased in a rubber cover ( probably to reduce vibration ). it have two lines that run out toward the back of the car - and then one little rubber hose up to the fuel filler door - then the rest of the lines run toward the front - obviously one to the front distribution block - which I'd assume would be the largest

I'm having trouble getting the pump out - with the rubber cover it looks to be almost friction fit into it's mounting bracket - I don't want to break anything by trying to pry it up and out... any advice ?

Pazo

Yes, I agree easiest test pressure lines from the PSE pump and prime suspects are door/trunk actuators. But there are also several interior lockers that have actuators. The PSE pump is inside a foam rubber casing, a tight fit - you just draw it out (backwards). Attached is a list of connections from WIS (Workshop Information System). Use search, you can find is lot of info about the central locking leaks and pump issues.

DM914

All the lines that come out of the pump ( I removed the two little manifolds on the top ). and tested each line - they all hold vacuum. ( I have a vacuum brake bleeder with a gauge ) so that leaves me to believe that the actual pump is bad ..

I did manage to remove it - and got the case split .. I don't have a fancy test set up but if I put 12v to the motor directly it won't turn... although when it was in the car and I activated it via the remote lock it sounded like the pump was running ( weird ) I might plug it in with no vacuum lines hooked up and see if runs when I active it just to confirm that's the issue.

I pulled the pump section with the vane inside and it looks OK - so I've ordered a new motor for the pump - and I've ordered a used complete unit ( tested ) - so who knows - I'll either fix my original ( new motor ) or plop in the used unit and see how it goes...

the motor has only two connections - A yellow and a green wire that are soldered - green should be ground and the yellow should be 12v




thanks all to all the advice...