Mercedes-Benz Parts Catalog Mercedes-Benz Accessories Catalog Mercedes-Benz Technical Articles Mercedes-Benz Tech Forums
 
Follow Pelican Parts on Facebook Follow Pelican Parts on Twitter Follow Pelican Parts on Instagram Follow Pelican Parts on YouTube Follow Pelican Parts on Pinterest Follow Pelican Parts on Tumblr
  Search our site:    
View Recent Cars  |   Cart  | Project List | Order Status | Help    
 >  >
Fuel Filter(s) Replacement
 
Bookmark and Share

Pelican Technical Article:

Fuel Filter(s) Replacement

Steve Vernon

Time:

1 hour1 hr

Tab:

$12 to $25

Talent:

**

Tools:

Philips screwdriver, 24mm socket

Applicable Models:

Mercedes-Benz W123 (1977-85)

Parts Required:

Filters

Hot Tip:

Use the hand pump before attempting to start

Performance Gain:

Better running motor

Complementary Modification:

Change air filter

There are two fuel filters on the W123 300TD; one is on the supply line and is a clear filter, the other attaches to the lines and bracket behind the power steering pump. Changing the filters is easy and should be part of your regularly scheduled maintenance. One tip is to make sure you fill the metal filter with as much diesel as you can when installing and use the hand pump to move air out of the system, this will make start up easier after you have changed the filters.

When you are working with fuel always remember to take safety precautions; wear gloves and eye protection and work in well ventilated areas. Remember never have an open flame, space heaters or open incandescent lights near your project. Always have a fire extinguisher at arm's reach and make sure it is full.

Over the years your car may have been serviced by multiple people including previous owners and this can lead to parts replaced with different size fasteners and hardware. The sizes of the nuts and bolts we give may be different from what you have so be prepared with different size sockets and wrenches.

Our vehicle may vary slightly from yours as Mercedes redesigned systems and sub-system as the models developed over the years. If something is different on your vehicle please let us know and share your info to help other users. If you have any questions or comments or even a different procedure you would like to share please leave it below and please leave your vehicle information.

The two filters are located on the left side of the motor down by the fuel distribution pump (red arrow).
Figure 1

The two filters are located on the left side of the motor down by the fuel distribution pump (red arrow).

This photo illustrates the two filters; the clear filter is attached to the supply line and attaches to the hose where it enters the primer pump (red arrow).
Figure 2

This photo illustrates the two filters; the clear filter is attached to the supply line and attaches to the hose where it enters the primer pump (red arrow). The metal filter is attached to its mount by a 24mm bolt right beside the return fuel line (yellow arrow).

When you are changing the filters make sure to inspect the fuel lines as well.
Figure 3

When you are changing the filters make sure to inspect the fuel lines as well. The supply line on our project car (red arrow) uses a "cigar hose" which, as you can see, is roughly twice the normal size hose--compared to the return line (yellow arrow). This shape is normal, but it's always a good idea to inspect it for cracks. 

Use a Philips head screwdriver and disconnect the supply line (red arrow) and line to pump (yellow arrow) from the filter and remove the filter.
Figure 4

Use a Philips head screwdriver and disconnect the supply line (red arrow) and line to pump (yellow arrow) from the filter and remove the filter.

The clear filter allows for easy visual inspection; do NOT let your filter get to this point before changing it.
Figure 5

The clear filter allows for easy visual inspection; do NOT let your filter get to this point before changing it. Installation is the reverse of removal.

To change out the metal fuel filter use a 24mm socket and loosen the bolt on top of the bracket (red arrow).
Figure 6

To change out the metal fuel filter use a 24mm socket and loosen the bolt on top of the bracket (red arrow). This bolt holds the filter in place so make sure to have a hand under the filter when loosing it or it could drop once the bolt lets go.

The filter will be full of fuel when you remove it so keep it level.
Figure 7

The filter will be full of fuel when you remove it so keep it level. Installation is the reverse of removal and if you can fill up the metal filter with diesel before you install it, it will make the initial start up easier.

There is a small hand pump located by the fuel distribution pump.
Figure 8

There is a small hand pump located by the fuel distribution pump. This pump has been redesigned over the years so check which one you have, but our pump involved unscrewing the plastic top and then pumping the plastic piece. This will allow you to purge the air out from the system and allow for easier start up.

Bookmark and Share
Comments and Suggestions:
Gunay Comments: I think the hose on the Image 3 is intentionally meant to be shaped like that right? I think it is called diesel cigar hose.
August 31, 2016
  Followup from the Pelican Staff: I believe you are correct. The line is larger in the center on this model. I will have the article updated. - Nick at Pelican Parts  

  Search our site:    

View Cart & CheckOut | Project List | Order Status |  Help    

 

[Home] [Customer Service] [Shopping Cart] [Project/Wish List]
  [Privacy Statement]  [Contact Us] [About Us] [Shipping] [Careers]

Copyright © Pelican Parts Inc. -    DMCA Registered Agent Contact Page

Page last updated: Wed 12/7/2016 03:01:48 AM