W124 saloon fuel tank problem

[danthebarber]

I need to change my fuel tank sender but there is an obstruction inside the tank preventing me from fitting the new one; looks like plastic ribbed piping; anyone got any ideas what this may be?

 

[grober]

DIY w/pix -- W124 fuel sender disassembly/cleaning/testing - PeachParts Mercedes ShopForum

and

W124 fuel tank removal tips - PeachParts Mercedes ShopForum

Not sure from your description but could it be the fuel outlet strainer? Have you got the correct sender unit?

 

[danthebarber]

Thank you for your response. Its the correct unit; I had trouble getting the faulty sender out; If you look into the space where the sender is supposed to fit into the tank (centre top) you can see what looks like an internal plastic? part that appears to have dropped down blocking the space needed to insert the sender; no-one appears to have knowledge of this problem; mines a 93 saloon facelift and was wondering if anyone knows if the internal workings of the petrol tank have some sort of plastic liner or fitting

 

[grober]

Might be the fuel tank vent system Fuel tank issues (pinhole leaks, vent question) in 87 300D W124 - PeachParts Mercedes ShopForum

 

[kth286]

seems puzzling.

You could be catching on that central vent pipe system.

Are you getting the sender unit vertical enough when trying to refit into tank?

is the sender sealing ring still fixed to tank and getting in way ?

perhaps an old sealing ring is still there from a previous replacement.

Is the tank starting to collapse from a vacuum fault I wonder, and causing a restricted space.

Do let us know how you get on as it is an interesting problem, and we can all learn.

 

[kth286]

Having another 'think' about your problem, it seems you have omitted to remove the 'sealing flange' which is recessed and screwed into tank.

You need to remove this (by unscrewing) BEFORE you remove the fuel gauge sending unit.

 

[danthebarber]

Thank you for the responses; I cut the plastic plug off the old sender (after removing it by breaking the cylinder part piece by piece to get it out) in order to continue using the car (I replaced the cut plug with an o ring & sealing nut); It may well be the central venting pipes that are obstructing the pathway for the new sender to be inserted; it appears to have dropped over the aperture but have tried in vain to find an internal pic or diagram of this model fuel tank; reluctant to change tank as the tank itself appears to be perfectly fine apart from this problem

 

[kth286]

if you go to the link posted by grober in post 4, then scroll to bottom of first post in that link, there is an attached pdf which shows the internal vent pipe system for the tank of 124 saloon.

The part number of the flange unit that screws into tank (before you insert the sender unit) is: 2014710521.

 

[kth286]

That part number for flange is listed at £13.08 from Merc dealer parts dept. (includes VAT) ask for discount.

Always give VIN to dealer.

 

[Vegi Rich]

I have a w124 M reg saloon diesel. and seem to be running out of fuel at a 1/4 full. if it is the sender where is it located and how to remove please. I have a petrol version in garden for spares, should I use the sender from that or buy a new one? Any help please. Rich. Have just read Grobers piece. very useful. will give it a go. Rich