fuel filter change
 

hello all changing the primary and secondary fuel filters on a 1983 300sd any thing i should do before removing?:confused:

Loosen brass nut on top of primary filter adapter then holding nut unscrew the canister filter. Secondary filter, loosen hose clamps twist and remove filter. Fill the new canister filter with diesel prior to install. It might start then die. Restart it to purge air from secondary filter. Once running you will see a small bubble of air in the secondary filter, normal. Some people for some reason have a hard time restarting because of the air introduced in the fuel line. If thats the case, remove the air cleaner lid and spray WD40 thru the air intake while someone else cranks the engine over. Wash hands open beer!

thanks alot carnut im new to mb and dont have the manual yet just wanted to make sure the germans werent making it to complicated

I would change the secondary filter first as stated. The secondary filter is the one that looks like a spin on oil filter. Get an adjustable wrench and hold the bolt head at top and try to spin the filter off as you try to loosen the top bolt. Once it is loose the secondary will spin off. Try to fill the new one with some diesel and spin it back on loosely (for now). Next grab a screwdriver and loosen the hose clamps on the primary filter. This is the clear one on the driver's side of the engine. Replace it and tighten clamps.
Now, right next to the clear primary filter is your primer pump. Unscrew the plastic wheel until you can pull it out a little and it becomes free. Start pumping! It may take quite a few pumps but after a while you will see fuel start to come out of the top bolt of the SECONDARY filter. When the fuel comes out snug up the bolt. Then push in on the pump and screw it back in.

Your car should start after a few cranks.

That`s the way to do it:).

might want to park over some gravel etc... or place some pans under the
vehicle to catch any spills.
The secondary filter will be full to the brim, so be careful tipping it. place
some rags under the filter helps to catch the spills.

Charlie ☺

(I would get these before you start.) If you central bolt has a metal washer copper or aluminum you will need a new one and a new "O" ring for the central bolt.
Some central bolts do not have this washer and some central bolts have 2 "O" rings.
I changed my primary filter thinking I could do it without changing the "O" ring and It leaked. I was able to find a new one that worked from a "O" ring assortment that I bought long ago from Harbor Freight.

Lots of torque on the secondary (spin on). Way more then you would suspect to be necessary.

Maybe, maybe not, similar to an oil filter on a gasser, there is a rubber seal. SOME engines have a crush washer under that bolt, some don't.

We, as a site, did not warn a new guy that if his tank vent is plugged and he did not relieve the pressure on his tank before starting he could end up taking a diesel bath. He was pissed that we didn't cover everything that could possibly go wrong.

Be safe, before you start take you tank filler cap off and then put it back on. :rolleyes:

-Jim

Filling the secondary filter with transmission fluid is a lot less messier than using diesel fuel.

:D

I know whom you're speaking of. Except he wasn't a new guy.

Transmission fluid
 

If the fuel cops check you tank, transmission fluid will show up as offroad diesel. The red dye is the same type.

MUCH more of a problem for the guys driving F-350 pick up trucks than for guys driving MBs.

-Jim