First Time Changing Both Fuel Filters
 

I'm about to change the fuel filters on my 1984 300TD. I wanted to do this before I mess with the linkage. I'm going to follow this video's instructions.

http://www.youtube.com/watch?v=A3iJ5rTBwe4

Do I need to have the fuel drained before I do this? I know he mentions a clamp but are there any surprises I might encounter like spewing/spraying fuel? Is it necessary to fill the secondary filter with fuel or can I install and then prime pump it?

digi

Nope you do not need to drain the fuel tank - this is basic maintenance.

Spewing and spraying fuel? Unlikely. Like in the video cover your car with rags if you are worried. Try not to get too much diesel on your skin or your clothes.

You do not have to fill the large spin on filter with fuel - but it makes the bleeding process with the pump go a bit faster if you do.

Beware of how-to videos from a person who doesn't even know which filter is primary and which is secondary!!!

In my experience, if you fill the secondary filter to the top with something like diesel, atf or purge, you will not have to prime.

Good point.

I've never had a need to prime the primary filter. Fuel runs into it from the tank.

I thought he got that wrong - but I couldn't be bothered to rewind to check...

No you don`t have to drain the tank. he said he was doing some other work, and that is why the tank was empty.

I did notice he used the primer pump, then started the engine. so there might be a time laps between installing the filters, and finishing the other job, before getting back to the priming and starting the engine.

The fuel system is not under pressure from the tank to the filters. so no, you won`t get sprayed with fuel.

If your tank is full when you pull off the little pre-filter, fuel will flow out the hose from the tank. when I change the pre-filter, I loosen both clamps, pull off the the supply line to the filter. quickly shove on the new filter, pull off the old filter. fuel will fill the new filter, then pull off the old one and attach the new filter to the hose on the other end. this way there is nothing to prime, as no air is getting in.

There will always be an air bubble in the pre-filter, that is normal and won`t cause any trouble.

The spin on is like he shows in the video. Just fill it to the top and tighten the bolt. then push the primer to purge out any air until you hear a buzzing or whoosh sound of the fuel flowing.

He mentions changing the one rubber "O" ring on the bolt. I would go ahead and change both. to me doesn`t make since to do just one.

Be sure to apply some Diesel onto the new rubber filter gasket. If not and the rubber is dry, and the filter spins, the gasket could bunch up and create an air leak.

I have read where some members pour the old fuel from the old filter into the new filter. Do not do this, you are just adding contaminates to the new filter and system. Use clean fuel. ATF, Diesel purge, even engine oil in a pinch, can be used to fill the filter w/o any harm.

If after starting the engine, and it kicks, bangs, snorts and makes some nasty noises, don`t be alarmed too much, probably some residual air that was not purged. It should smooth out.

Charlie

Dang, you guys beat me. there were no responces, I thought I got firsties.:D

Must be a slow typer or long winded.:rolleyes:


I didn`t pick up on it the first time he had the filters name switched. Had to rewatch it.
Other wise he is pretty much right on.

Charlie

Man this forum is amazing! So many responses in less an hour!

Well, my local auto parts supplier only had the primary fuel filter. So I'll do that one first. I guess I'll have to order the secondary online. Not sure when the filters were last changed.

Thanks so much! I'll let you guys know if I end killing my car.

digi

Yeah, for those that haven't done so, try removing the clamp on the inline PRIMARY filter closest to the primer pump first. Once removed, lift the filter up and let the fuel drain into the fuel line, THEN swap out the filter. Doing so, you won't spill a drop. You saw how he emptied the contents of the filter into the rags, unnecessary.

Also, try and move that first clamp around so you can access it from the fender side of the fuel line, you see how he has to bend the short line to get a screw driver on it.

The SECONDARY filter can be swapped out with very little spillage as well, he edited out that section.

It doesn't hurt to change the filters when the engines warm and the 'spin on" is full to the top with clean fuel or Moly Purge, your engine will never know its fuel system has been opened:P

Ok I changed the primary fuel filter. Had no idea it was that simple. The old filter had a bunch of black sandy stuff in it. Well I'm going to order the secondary filter in a few minutes.

Thanks so much for all the help!

Digi

you will find that most of the repairs your car needs are easy if you have the right tools. that oil pan replacement is really a piece of cake. trans mount easy too.

Changed both of mine tonight for the first time. Wasn't too bad, but I made quite the mess! :silly: I should do better next time.