This is for maclaveau - PeachParts Mercedes-Benz Forum

Diesel911 · #1 06-05-2014, 12:15 AM

Please note that this is only for MW Fuel Injection Pumps if the O-ring at the Bottom of the Element and the Body is leaking.

Also note that this represents the best that you can do under the circumstances in sort of an emergency situation where you want to try this before getting another Fuel Injection Pump or sending the Fuel Injection Pump to a Fuel Injection Shop.

For this to have anychance of working you are better off removing the Fuel Injection pump.

Do one and only one Element at a time. On the Engie Side of the Fuel Injection Pump scribe an accurate and deep line. You may need a Tungstan Carbide Scribe to do that. Scribe the line acrossed the Element Flange, the Shim and the Fuel Injection Pump housing. Pics 1 and 2

On the opposite side of the Fuel Injection Pump use one of the Elements you are not going to remove and measure from that to the Element you are going to remove.
You can use what ever spot you feel is most accurate just remember where you took them and write down the measuerment. See pic 3

Remove the 13mm Nut and washer off of the one you marked to remvove and pull the shims our of each side.
The shims each Shim is supposed to be the same size but to be sure sort the shims so that the go back into the same place and face the same directions.
Use a Screwdriver on each side and gently pry up on the Element. Pry with the Blade pushing against the Steel parts. And, the Plunger should come up and out.

Diesel911 · #2 06-05-2014, 12:31 AM

In My case the Plunger remained inside of the Fuel Injection Pump. I hope that happes with yours so you can leve it tehere. Notice one side of the Plunger has a Notch in it and which way the Notch points.
It was pretty dirty due to the Oil dripped on it and I later hosed it down with WD-40. Do not hose it down with Brake Cleaner or any thing that will leave it dry because if it rusts you will ruin it.

Note Picture of the pulled out Element and where the parts go. In My case the O-ring and Spacer came out with the Element but I guess it is possible for them to remain inside of the Fuel Injection Pump.

Remove the O-ring and Spacer. Take a good look at the Spacer to see if it is rusted through or rusted on the rounded face to the extent that the O-ring would not seal on it. If the Spacer is in bad shape you will need a new Spacer.

The Spacer has 2 sides to it. the rounded portion goes against the O-ring.

Clean everthing and hose it down with WD-40 so it won't rust. Be sure to hose out the bottom inside of the Element with WD-40.

Install the Spacer on the Element in the proper direction and then insall the new O-ring.

Spry WD-40 on the Element Plunger that is still inside of the Fuel Injection Pump and Lube up the Element O-ring (I have a Bottle of Generic STP I use for that sort or thing). Only lube the Oil Ring enough to coat it you don't want any Lube to get inside of the Element or on the Plunger.

Extremely carfully bring the Element down over the Plunger inserting the Plunger into the Element. Turning the Element a tiny bit back and forth may help.
Don't force the Element onto the Plunger or it will get stuck and damaged. You sort of what the Elements weight with a tiny amount of assistance pressure to bring the Element Down.

Install the Shims back where they came from and line up the Scribed Marks. Install the 13mm Washers and nuts.

OK the Torque Spcs on the 13mm Nuts are 20-25 Nm (Newton meters). I would use a good quality Torque Wrench and devide the torque in 1/2. Exampel; Torque one nut to 12 Nm go to the next and do the same. Go back to the first and torque to 25 Nm and do the same to the other Nut.