Cleaned my tank screen today... - PeachParts Mercedes-Benz Forum

MercFan · #1 11-18-2009, 12:19 AM

I've been trying to avoid this job because it's messy and time consuming, but after syphoning some fuel that looked like black death and seeing not so good signs in the once-clear primary filter I've decided it's time to pull the tank screen out and clean it out.
I knew it wasn't gonna be pretty but what I found was downright shocking... not even sure how that car managed to run as well as it did thus far. And no, I don't think it had the return and supply lines swapped - I checked. There was a lot of tiny air bubbles in the pre-filter and the filter itself had a lot of the black gunk in it too...

The screen was so clogged with junk that when I pulled the fuel hose from the supply line to drain the tank it barely flowed - I mean barely a trickle... when I pulled the return it flowed a LOT better and that's how I drained most of the fuel - took pretty long time. No problem removing the large 46mm nut - it all came out just fine. Once removed from the tank I've filed off the brass fittings around the hoses exposing the barbs - I have Viton lined hoses (7/16th) and good clamps ready for re-install.

I've decided to go for broke and pull the whole tank out and clean it. This is where I have some questions: I've removed 4 nuts and washers inside the trunk securing the tank to the back seat behind it. I've pulled out the gooey tank filler large rubber grommet. Underneath I've removed the vent hose by pulling it off the nipple - so by all appearances I'm ready to pull it out, but it seems stuck in there. Either it's very heavy or something is still holding it. How is it supposed to come out - from left side, and up, or some other way?!

Thx

Ian White · #2 11-18-2009, 12:26 AM

I believe the tanks come out through the passenger cabin.

scrivy00 · #3 11-18-2009, 01:45 AM

http://www.peachparts.com/Wikka/W123FuelTank

post about removing fuel tank

NJ300sdl · #4 11-18-2009, 06:16 AM

It is not heavy. The tank settles in on the mounting pads and studs, holding it in position. Try moving it up and out.

oldsinner111 · #5 11-18-2009, 06:24 AM

I drained tank,filtered fuel and saved it.
Then put 6 gals. gasoline in tank,and my teenage son's stood in trunk ,and shook car for 30 mins.
Drained put my diesel back in,filtered gasoline for truck.

rs899 · #6 11-18-2009, 06:54 AM

Sounds like you have all the fasteners and everything else that could be holding it. I know for a fact that it won't come out without unscrewing the hose from the strainer. Just give it a good up and out pull- you may even need to gently pry up as the bottom grommets really get stuck on the tank after so many years.

It's a great idea to pull the thing out once you have drained it and really not that much more work.

Rick

dieseldan44 · #7 11-18-2009, 12:45 PM

dont forget the filler neck! you need to remove the rubber grommet around the filler neck.

Back the left side of the tank off the studs first, tilting the filler neck to do so. Then remove it off the right side studs. Removal happens to the left rear.

It comes out pretty easy once you have the technique.

Put a towel down in the trunk. diesel is going to spill.

dd

leathermang · #8 11-18-2009, 01:14 PM

That reference is for a 240... a 123..... and my car that I am about to describe is also..
I have posted about this before.... somewhere in the archives..

I took my 1980 124 240d tank out and took it to the car wash in the pickup truck and cleaned it with the power wand...

But I would not do it that way again if I had any access to any pressure washing devices...

Because the holes in the tank... the fuel gauge connection at the top of the package shelf , the fill hole, the tank strainer hole ( is that all ? )

Are all in perfect position to clean out the inside without taking it out of the car.

If you have all of them out and use even a good adjustable nozzle on a water hose you should have no problem getting it cleaned out...
Mine was exceptionally clean before I even started... but my tank filter did need to be cleaned...

So if you take off the fuel lines and cover them with a couple of wraps of aluminum foil and baggies secured by rubber bands, clean the filter with a tooth brush and replace the filters up front before putting fuel back into your 123 you can save some fitting up work taking the tank out and putting it back in... although that is not particularly hard either... a very nice design.... but I do remember that it it is held with some friction by the rubber mounts and I had to push harder than I thought I would to get it back in place. Just real firm...not excessive.

IT would certainly be a great time to replace that section which connects the fuel input shaft to the tank also... and perhaps the rubber seal at the top also.... and perhaps your fuel cap...

rs899 · #9 11-18-2009, 01:23 PM

Are you saying to clean out the inside of the tank with a pressure washer and leave it in the car?

MercFan · #10 11-18-2009, 02:09 PM

I'm going to pull it out tonight and either use gasoline, or home brew biodiesel of which I have plenty. That way I can filter it out at the end and re-use and any residual will not be harmful.

I wont be able to power wash it but I'll give it a good cleaning; maybe even put some in a large sprayer bottle that I can pressurize and squirt it in there as best as I can to get some crud off the walls and especially bottom. Will let you know how it goes.

leathermang · #11 11-18-2009, 03:32 PM

After doing it with it out of the car ...
yes, I would do it in the car the next time myself....
You have to do all the unhooking and rehooking either way...
but the hassle with the moving rubber snubs at the bottom would be avoided...

rs899 · #12 11-18-2009, 03:44 PM

leathermang-

Still not sure what you are saying but if you are suggesting flushing out with water with the tank still in the car you will never get all that water to drain. Bad bad for the bugs and IP.

Rick

leathermang · #13 11-18-2009, 04:06 PM

Quote:

Originally Posted by rs899

leathermang-
Still not sure what you are saying but if you are suggesting flushing out with water with the tank still in the car you will never get all that water to drain. Bad bad for the bugs and IP. Rick

LOL.
You have some big holes to work with...
put the car at a slight angle,
put a long piece of cloth into the tank with the end hanging out the bottom and leave overnight..it will siphon out just fine...
Then ,if you are really worried spray a quart of alcohol into the tank ... and then add your fuel...
but it really is not a problem.... because you get water inside the tank from the pump and condensation regularly anyway...

rs899 · #14 11-19-2009, 06:53 AM

Maybe you can get away with that in Texas, but in Florida I wouldn't want more than a few drops of water left in my tank. I am constantly adding Heet (for diesels) to keep the water and humidity out of my tanks to try to keep the algae under control.

Rick

MercFan · #15 11-19-2009, 01:46 PM

Finally pulled it out last night with my dad's help - turns out it was held by some sort of sticky tape to the back of the seat. I gave it a gentle steady pull out and up and it came right off. Looking inside with a light scope it looked nasty - just like the tank screen did (no wonder), so we took it to a local car wash. Sprayed some engine cleaner in there and let is sit for a while. We then sprayed it out with hot soapy water from the high pressure nozzle. Some Purple Power and some more time, plus another spray and rinse. Looked inside and it looked squeaky clean.

Back at home I hooked up an old hair dryer to the filler neck, securing it with the omnipotent duct tape - I let it run for few hours on low. When I came back few hours later the tank was dry inside. Plan on reassembly soon, though I have to wait for the rubber o-rings for the Fuel Screen on the bottom and the fuel sender on top. Forgot to order those from Phil, so I'll get them from local dealer in next couple of days. Meanwhile, I can carry on with the multitude of other tasks...

Thx for all the advice thus far -

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