Mercedes-Benz Forum banner
1 - 12 of 30 Posts

· Registered
W140 S class, E31 850Ci, XC90 Exec AWD geartronic
Joined
·
444 Posts
Vacuum pump

Over the last few days, my 94 W140 has developed the symptoms.

(1) Central locking failure
(2) Parking Aides down
(3) Boot handle stuck in the 'out' position

Like Trent S320, I've checked the obvious like fuses and nothing seems to be wrong. The vacuum pump under the back seat doesnt make any noise. Where do I start? Should I open the pump up?
 

· Registered
W140 S class, E31 850Ci, XC90 Exec AWD geartronic
Joined
·
444 Posts
Can you tell me which fuses to pull? I know the location of two fuse boxes, One in the t...

Can you tell me which fuses to pull? I know the location of two fuse boxes, One in the the engine bay by the windshield and the other in the trunk behind the fuel filler down pipe

Thanks
 

· Registered
W140 S class, E31 850Ci, XC90 Exec AWD geartronic
Joined
·
444 Posts
Here is the story so far......

About 3 months ago I noticed later that the lumbar support didn’t feel right and my seats felt saggy, I tried to adjust my support and the system didn’t respond. This was also the case with the front passenger seat.
In the winter (about two months ago) in exceptionally cold snowy weather, the central locking system died in my car.
I could unlock the doors individually with a key.
I assumed it was likely a fuse had blown and didn’t think too much of it.
Later that day I opened my trunk and the handled (very slowly) popped out and didn’t return when closing the lid. On further investigation I noticed that my parking aides no longer popped up when reversing and my headrest down function didn’t work.

I disconnected the battery for about 10 minutes and tried again. The locks started working for about 10 seconds and then died again. I could still hear the relays clicking beneath the rear bench, but no action.

I lifted the back seat to access the pump unit. All hoses/connections appeared fine and intact.
I carefully, labeled all the hoses and then disconnected them one at a time.

I started the car and connected the live hissing hose by hand to each of the lines. All devices operated with connection and I was able to 'down' my headrests, 'in' the trunk handle the by connecting the appropriate hoses.

This means there is no leak in the hoses and the engine is still supplying the vacuum.
The clicking of the relays also suggests that the controls are still working and current is being sent to the pump.

I removed the pump, opened it and examined the insides. There was a red coloured hose with looked worse for wear so I tried to replace it with a new vacuum hose (a small piece of windscreen washer hose) which fit snug and well. While the unit was open I examined the PCB for breaks in the solder and wiring which may have occurred due to fatigue. I also took it on myself to clean the contacts in the vacuum micro switches with spirits. I then reassembled the unit, reconnected the hoses and tried again.

No joy. I reckon the pump has had it. I am now faced with buying a new pump. Does anyone know much these units sell for? and what are the options/costs for getting a rebuilt unit/ or one from a breaker.

I don’t know of any supplier other than the main dealer.

I am open to all suggestions and help you may have to offer
 

· Registered
W140 S class, E31 850Ci, XC90 Exec AWD geartronic
Joined
·
444 Posts
thanks for the speedy response...

Hi again Peter,

When the device is activated, I can hear the relays clicking. I do not hear the familiar whine from the pump - hence it's not starting.

I dont think its the red hose, I've already tried replacing it.

As per your suggestion I'll steer clear of breakers and contact the dealer on Thursday to find out the price of the pump

By the way my car is a 1994 LWB S320 - now developed transmission problems (flaring between gears / hesistant to upshift) ...SIGH...
 

· Registered
W140 S class, E31 850Ci, XC90 Exec AWD geartronic
Joined
·
444 Posts
Ouch...

Hi again Peter,

When the device is activated, I can hear the relays clicking. I do not hear the familiar whine from the pump - hence it's not starting.

I dont think its the red hose, I've already tried replacing it.

As per your suggestion I'll steer clear of breakers and contact the dealer on Thursday to find out the price of the pump

By the way my car is a 1994 LWB S320 - now developed transmission problems (flaring between gears / hesistant to upshift) ...SIGH...
I just called some suppliers of Merc parts, here's the responses

Eurocarparts - We dont do that part
German and Swedish - We do vacuum pumps for just about every other model for about £90+vat apart from the W140 S class
Mercedes Benz main stealer - Part has to be ordered in from germany. To supply only it will cost £412.34+vat

For those of you in the states, vat is value added tax 17.5%

OUCH!!!....I am at the end of my tether, I am going to try and fix the old one again!!! [xx(]

Mmmm...I wonder if I can buy the one for £90+vat and use common parts to re-build my own one [?]
 

· Registered
W140 S class, E31 850Ci, XC90 Exec AWD geartronic
Joined
·
444 Posts
can you send me the full link for germanstar.com - I get a pen retailer when I try that ...

can you send me the full link for germanstar.com - I get a pen retailer when I try that address.

Thanks [:)]
 

· Registered
W140 S class, E31 850Ci, XC90 Exec AWD geartronic
Joined
·
444 Posts
Thank you //S320Can you imagine my horror when The dealer quoted me £412.34+VAT !!! = ...

Thank you //S320

Can you imagine my horror when The dealer quoted me £412.34+VAT !!! = about $762.23 US [xx(]

I will buy from Germanstar.net as soon as they reply to my e-mail with a delivery quote to the UK [:)]

Thanks again
 

· Registered
W140 S class, E31 850Ci, XC90 Exec AWD geartronic
Joined
·
444 Posts
Hi again,

I just had a reply from german star, They have quoted $45 to send the unit to...


Hi again,

I just had a reply from german star, They have quoted $45 to send the unit to the UK.
Can you tell me what a MOD kit is and why I would need one? Germanstar did not quote me a MOD kit or tell me I needed one
 

· Registered
W140 S class, E31 850Ci, XC90 Exec AWD geartronic
Joined
·
444 Posts
Re: Re: Hi again,I just had a reply from german star, They have quoted $45 to send the unit to

Hi again,

I just had a reply from german star, They have quoted $45 to send the unit to the UK.
Can you tell me what a MOD kit is and why I would need one? Germanstar did not quote me a MOD kit or tell me I needed one
Hey Gill,
I dont know what a mod kit is. But when i called germanstar yesterday, the guy told me about the mod kit. But did not tell me what it is for. You might want to email and ask him..I think his name is Ron.

[}:)]
I placed my order today. Here is my reply......
Yes a $25 modification kit is required to convert when replacing a 19 48 with a 28 48. The 19 48 is no longer available hence the different part number and the modification requirement.

Ron Parker
German Star Mercedes Parts
http://germanstar.net
(800) 377-6598
 

· Registered
W140 S class, E31 850Ci, XC90 Exec AWD geartronic
Joined
·
444 Posts
fitting procedure

The pump arrived on Friday, delivered by FED EX airmail just a few days after I placed my order. - WELL DONE GERMANSTAR.NET !

I opened the package and examined the new pump. It looked considerably different to the older one. The old pump (p/n 140.800.19.48) had 15 hoses, which plugged directly into the pump. This newer design pump had only 6 input connections. Germanstar had also supplied a MOD kit to accommodate the changes between the two pumps. This MOD kit consist of

about 3ft of vacuum hose
2x 6 way connectors
6x 1 way straight connectors
2x 2 way connectors
4x vacuum plugs
Mercedes Benz Bulletin fitting procedure

The newer pump (p/n 140.80.28.48) has been standardised with connections for all the various accessories. This eliminates the need for different pumps for each model. Vacuum plugs are supplied to cap any connections in case the vehicle is not fitted with a particular accessory.

The connectors on the old hoses are the incorrect gender to fit the newer pump.
The service bulletin supplied, advises to cut the old connecter off and replace with the a new connector of the correct gender The two six way connectors require you to use a 12inch length of vacuum hose between the connector and the pump.

I found that new connecters did not fit at all well on the old hoses. The problem was that the hoses we not have a big enough diameter to slip over the new connector. I tried using lubricants, and a heat gun to no avail. I gave up after a few hours trying and used one inch lengths of vacuum hose connecting between the connector and the hose.

The vacuum lines are grouped together as follows:

Clear = Vacuum supply from engine (1) to fit to a one way connector
Black = trunk handle eject/retract (1) to fit to a one way connector
Red = Rear parking aide antennae (2) to fit to the two way connector
Yellow = Central locking (6) to fit to the six way connector
Grey = Front seat lumbar (3) to fit to the six way connector with 3 vacuum plugs
White/blue = Rear headrests (2) to fit to the two way connector

Once these are all connected to the pump plug in the power and it should all start working, as it should again. Even my saggy front seats filled with air again after being out of action for some months before my pump failed outright.

If anyone has a failed pump and wants to retract a particular accessory, disconnect the clear hose and link it directly to the hose of the accessory you want to operate with the engine running. I found the useful to retract my parking aides and trunk handle, which were stuck in the 'out' position for a few weeks before the repair.

I have taken loads of pictures documenting the procedure. If there is enough interest, I will post a pictorial.

Thanks to everyone who helped me diagnose and source a pump.
 

· Registered
W140 S class, E31 850Ci, XC90 Exec AWD geartronic
Joined
·
444 Posts
Peter Guenther - 4/24/2004 1:07 PM

tipstas37 - 4/25/2004 10:59 PM

Wow......I'm about a year or so late w/this same problem. Your info is very appreciated and valuable. Pics would be great if you still have them or tell me where I can find them. I need to isolate if I need a new pump or hopefully just the hose inside that I have read postings about. My locks, rear anteneas,rear trunk lift handle, and lumbar are all inoperable. Both sets of headrests ARE working.(I heard they were related to that same pump). Also my drivers front door stop working w/the key inserted. It turns but has no resist or pressure when turning.I have to unlock the passenger door first[xx(] Do you think that is a related problem to the pump failure or just another costly coincidence? Thanks again for your previos posts!!!
All of those are controlled by the same pump, and by fuse. The rear headrests are electric in the 500SEL.
Agreed, Sounds like total pump failure
 
1 - 12 of 30 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top