German Spec 1992 W140 500SEL Questions - PeachParts Mercedes-Benz Forum

mechahayai · #1 03-03-2010, 01:55 PM

Hello. I love this car. My last few vehicles have been Toyota Land Cruisers. This is my first MB. I've put about 1600 Autobahn miles on it since I bought it three weeks ago.

I have some questions. Where can I get a Factory Service Manual or a good repair manual as I've heard these are maintenance intensive cars. I kept my Land Cruisers on the road by doing the maintenance on them myself. I'd like to do the same for the 500. I'm the third owner, 175km, always garaged/maintained and everything worked on it up until tonight. It has the ortho seats and everything else, but traction control. It doesn't have the close assist AFAIK that the state-side versions seem to have.

Tonight the central locking system quit working. I unlocked the car, got in and started the car. The dome lights stayed on and blinked a bit. I've done some searching on here regarding the pump. I don't know exactly where it is or how to get to it. I can unlock the doors and trunk with the key manually, but the trunk handle doesn't pop out like it did.

Also, the auto-up/down feature on the windows quit working on all four windows tonight too. I can roll them up/down so long as I don't click it all the way to the auto.

What started all this was is I dropped by the shop to pick up an air pressure guage as my left front tire is wearing on the outside. I thought it was the air pressure, but it's fine. I assume it needs an alignment. I'd appreciate any tips on that and tire suggestions as I'll probably be replacing them soon. My tire pressure is 40psi. I assume that is what it ought to be. I was surprised it was that high though. I guess it sensed it was near a shop and decided to give me something to work on.

Thank you in advance for any and all help!

Chad

Mercedes Guy · #2 03-05-2010, 11:46 PM

Congratulations on your purchase. The 140s are very nice vehicles. I can't answer all of your questions, but I'll do what I can.

Here in the U.S. the best service manual for the 140s is the CD manual available through any authorized MB dealer. You might want to check with an MB dealer to see if they can get one for you.

If I remember correctly, the pump for the central locking system is located beneath the rear seat. I don't remember if it's on the driver or passenger side. Before you go taking out the seat you'll want to check all the fuses first. Keep in mind that there are two fuse boxes. One is under the hood on the driver's side right in front of the firewall and the second one is in the trunk on the right hand side directly above the battery. There are lists in each box which will allow you to locate the correct fuses to check.

40 psi in the tires is quite high. The recommended pressure for my 140 is 28 psi all around for a normal load and 28 psi front/34 psi rear for a heavy load. Good luck. I'm sure that once you get these minor issues resolved you will be very happy with your new 140.

300sdlguy · #3 03-06-2010, 02:22 PM

I have a Euro S600 Coupe the pump for the doors & trunk is in the trunk next to the fuel tank resting on the wheel well (all behind the trunk lining). There are some pumps under the right rear seat. Mine quit working and it turned out to be a cracked line someone had tried to fix with some rubber vacumm hose, but it wouldn't hold so I used small zip ties on each side to keep it from blowing apart.

With respect to your windows. Sounds like the auto up/down needs to be reset. For each window: roll down the window once it finished, push the button down so you feel it click, hold for 5 seconds, then release and roll the window UP only pressing the button enough to move the window, then when it is completely rolled UP, press the button fully and hold for 5 seconds. You have to do this for ALL windows separately.

Peter Guenther · #4 03-06-2010, 06:54 PM

The dvd from MB is under $100 but does not run on anything newer than XP and Arobat 5.5
Try this source
http://books4cars.com/
or mb
http://www.startekinfo.com/StarTek/outside/9124/?requestedDocId=9124

mechahayai · #5 03-07-2010, 08:32 AM

Thank you for all your replies. My computer is running on Windows 7, but I'm sure I can find an older OS to make the DVD work. I was able to find an old post relating to the pump under the rear passenger seat and the #11 20 amp fuse blowing which is exactly what I have. I just found out that the gas cap lock is also on this same pump when I went to refill a moment ago. I'm going to put another 20 amp fuse in there and see if I can coax the pump to unlock that fuel door.

It seems all these cars are a bit different. Everything on mine including the headrests and other interior parts work, but the locks and ortho seats. On the exterior it's the reverse rods, trunk handle and gas cap lock.

If anyone has any suggestions or experience with removing the rear seat on a 92 500SEL please let me know. I can see the two red levers under there that look like they slide or something. I'd like to get this fixed as soon as I can. There's a guy on a UK W140 forum over here that says he has a fix for it, but his last post was a couple years ago. Hopefully, he's still around.

Peter Guenther · #6 03-07-2010, 09:15 AM

Move the two levers and the seat will lift up, make sure you disconnect the seat heaters if you have them and take seat out of the car. The locking pump is in a foam covering near the outside rail under the passenger seat. if it is the origional you will have hoses plugged into a plenum on the pump. The yellow lines are for central locking, the orange for back up rods, the black for trunk lid grip, the gray for orthopedic backrest, and the clear is for backup engine vacuum when it is not running. The fuel door is also part of the lock and unlck system. Your head rests are probably electric, the pump does fail eithe thru water, moisture, brushes, etc. they are typicly available for about $500
There are three cables from the door locks, from the alarm system, and door sensors. The pump sets its start command from the key cylinder microswitch. It also gets a command from the infrared control module (remote) via the sensors on the door and trunk. The pump runs untill it reaches 600 mbar in the lock and unlock function, but no longer than 10 seconds if there is a leak. It provides pressure to unlock vacuum to lock. The secondary timeout for lumbars etc is 60 seconds, but will run to replenish the pressure for the lumbars and vacuum for the HVAC which is stored in a reservoir.

I you have the newer universal pump there is no plenum rather a series of fittings and "t"s
The US versions had a standard soft close option which would draw in the doors, that pump is located on the top of the drivers side rear wheel next to the fuel tank which has a number of red hoses going to it.

mechahayai · #7 03-07-2010, 09:34 AM

Thank you very much for that! Mine does have heated/reclining rear seats. I found a post on here that explained how to manually unlock the fuel door. It's all gassed up now.

pawoSD · #8 03-07-2010, 10:04 AM

Quote:

Originally Posted by Peter Guenther

The dvd from MB is under $100 but does not run on anything newer than XP and Arobat 5.5
Try this source
http://books4cars.com/
or mb
http://www.startekinfo.com/StarTek/outside/9124/?requestedDocId=9124

Wrong, I use it on Windows 7 all the time. It depends on the browser and version of acrobat. And you can view the files manually as well.

Also, windows 7 has "XP Mode" which is essentially a virtual machine of XP, you can use it in there and install the old version of acrobat.

For my own use I loaded all of the files onto my webserver and I can browse it anywhere.

mechahayai · #9 03-10-2010, 12:42 PM

I got off early from work today so I had time to play with the Merc a little. I have to say I'm impressed with how logical all the connections are in this car. I was worried I might break something, but I did what it looked like I should and everything just popped right out. All except the pump. I didn't realize you don't have to disconnect all the hoses individually to take the pump out until I brought it in and took a look at it.

That said, the pump looks brand new. It's the Bosch unit and may be the original. I don't know. I want to take it apart and fiddle with it. What, if anything can I do myself to check the function of the pump and the lines for leaks as I understand that if there's a leak somewhere that can lead to pump failure? I don't want to put another one in and see it fail too if I can avoid it. Thanks!

mechahayai · #10 03-10-2010, 12:52 PM

Quote:

Originally Posted by 300sdlguy

I have a Euro S600 Coupe. With respect to your windows. Sounds like the auto up/down needs to be reset. For each window: roll down the window once it finished, push the button down so you feel it click, hold for 5 seconds, then release and roll the window UP only pressing the button enough to move the window, then when it is completely rolled UP, press the button fully and hold for 5 seconds. You have to do this for ALL windows separately.

I tried your suggestion on the windows and it worked. Thanks for that!

Does your 600 have the height adjustable lights like the Germany cars do? Mine aren't moving up and down when I play with the dial now (they did until yesterday) and I was wondering what fuse/relay I could possibly check.

Also, does yours have the optional security system on it? Mine has the sensors on the B pillars, some kind of card thing in the glove box and another bigger unit under the glove box as well as another box under the rear seat. There's a sensor attached to the base of front windshield too. I don't know if that's standard or an optional part of this system. I have a brochure in German that explains the basic function of the system. I'll try to take some pics soon so you can see what I'm talking about.

300sdlguy · #11 03-11-2010, 08:37 PM

Glad it worked for you. Yes, mine still has the adjustable euro headlights. It is my understanding that the adjustment of them are strictly vacuum operated. Might have a leak from a dry or loose vacuum line. Mine has the extra trunk locking mechanism: option code 884. Otherwise, it's equipped with the exact same optional equipment that is standard on the US version 600's.

mechahayai · #12 03-13-2010, 05:22 PM

That's interesting. The headlight adjusters were working before I took the pump out. Now that the pump is out they're not working. Do you know what pump runs the adjusters?

300sdlguy · #13 03-13-2010, 11:15 PM

I am not sure, but maybe the pump you took out maybe ?!?!?!

Peter Guenther · #14 03-14-2010, 10:16 AM

I would suspect the pump, the pump runs forward to produce pressure for the locks and lumbars etc. and backwards for vacuum for lock and HVAC when the engine does not produce any. The are two storage reservoirs, the switchover (lots of hoses) is controlled by the heater control, the other block is used as a junction block I suspect that is where the headlamp contol vacuum comes from, my manual shows 3,4, and 8 thru 12 not used. The port 6 gets vacuum from the pse pump, and 13 goes to the vacuum storage reservoir. If the pump is removed maybe it is causing a backflow leak

mechahayai · #15 03-19-2010, 11:32 PM

Great. What tool is it that you use to check the lines for leaks? I ran across it in an old post. I'm here in the states for a few days and want to pick it up and take it back with me. I think it was called a mighty vac or something. I think it can pull a vacuum and pressurize the line IIRC.