Do I need to change my fuel tank filter
 

I have been running B100 for about 6 months now in my 82 300TD. Do I need to change the fuel tank filter and is this the right part for this?

The tank filter is a very course screen. Unless it is damaged, it should never need to be replaced.

I was running soy vegetable oil in my main tank for a while. I pulled the tank screen out when I parted the car, and it was completely slimed and mostly clogged. Biodiesel will keep that sucker real nice and clean, there should be no reason to change it.

Disconnect the fuel supply line from the tank to the primary filter. Remove your tank filler cap (where you put in the fuel). Blow back through the fuel line and feel the pressure. After blowing back the fuel into the tank the effort to blow air through the line should be minimal. Get someone to listen at the tank filler pipe to see if they can hear air bubbling easily into the tank. This will tell you if your tank strainer is clean. I cleaned mine in a 30 year old 115/300d and it was spotless even after all those years.

Cleaning or changing the strainer is not technically hard but it is messy unless you are really set up for it. Jack the front of the car and siphon as much fuel out of the tank as possible. Put the front wheels back on the ground and block them. Jack up the rear and set it on jack stands. I think the strainer is about 42mm dia. in which case an 18" pipe wrench will take it off. Mostly these strainers just need to be cleaned, not replaced.

At this point it might be to your advantage to take the tank out and clean it inside. It is not difficult and it will give you a chance to replace the hoses. You don't need a floor jack to do this but it will make it easier esp. if you are doing this job by yourself.

If you do decide to remove the screen, by all means renew the o-ring.

B100 is a powerful solvent and may dislodge any resduals from inside the tank and cause the in-tank sediment screen to clog. Same is true of biodiesel that has not been properly dried and may still contain micro droplets of water which will settle to the bottom and cause a sludge, cloging the screen and eventually starving the fuel flow to the engine.
Running B100 for 6 months though should have demonstrated any problems that were going to show up in this area, if there were any, and it appears that there are not. An option is to strip the screen and then install an in-line filter just outside the tank but as close to the outlet port as possible. This will catch any residuals from the dino but be simpler to swap out than opening the tank to get at the screen filter. If you have not experienced any fuel starvation in the 6 months you have run B100 then don't worry about the screen, unless you homebrew but don't dry properly. If you buy commecial biodiesel be sure of the vendor and that they are selling you spec fuel.