Gas Tank Removal-71 280se - PeachParts Mercedes-Benz Forum

mbgingerbread · #1 12-17-2008, 10:19 PM

I am preparing for major fuel system cleaning. I have consulted the manual I have and bolts have to be removed to get the tank out. Any suggestions for this task..............

Thanks...

Todd Miller · #2 12-17-2008, 10:27 PM

This is a good time to be wearing eye protection, and if you tie rags around your wrists it will keep fuel from running down your arms and burning the

out of your armpits.

alabbasi · #3 12-17-2008, 11:13 PM

Drain the tank first, you will need to undo the drain plug at the bottom of the tank. Once the tank is drained, removal is pretty straight forward. I think it's 4 bolts.

Make sure that you remove the plug before trying to flush else the fuel strainer will be blocked up and you wont get very far.

You will be amazed at how much crud will come out of that tank.

mbgingerbread · #4 12-18-2008, 08:03 PM

I intend to follow a procedure which alleviates any pretense at becoming a technomechanical sponge or potential backdraft victim-I have a great respect for gas because I have worked in the industry for so long. At any rate I will minimize the exposure to the gas both liquid and vapor.

On the cleaning side.....Do you recommend a steam cleaning by a professional and, also, I think I remember reading about cleaning the chamber which the discharge and return lines are attached to. Any trickiness here that you might be aware of?
Thanks, again

alabbasi · #5 12-18-2008, 08:12 PM

You can take it to a radiator shop to get it professionally cleaned out. with mine, it didnt look so bad so I Just used a little hydrochloric acid and a lot of water and let it sit for about 20 minutes then drained it.

flacollect · #6 12-18-2008, 08:16 PM

I used that "KREEM" gas tank liner and cleaner...35.00 at jc whitney. GREAT STUFF.....The inside of my tank is white inside now.. Might consider it for you own tank. Takes a week to do tho.

Dave

alabbasi · #7 12-18-2008, 08:19 PM

I was worried about using a tank liner because the W108 tank appears to have a tube that takes the fuel through the fuel strainer to the outlet pipe in the back of the tank.

The liner coating may block the tube and make the tank useless.

flacollect · #8 12-19-2008, 08:19 AM

Yes, it does have a tube, and you block it. Block anything you don't want this stuff in. Further, the tube, and the opening where the gas falls into has a void..you have to dig in there with an ice pic point to get all the crud out. Mine was full of rust, and dirt. I'm surprised gas got through it actually.
The screen wasn't dirty inside the tank, so I reused it, and the sending unit had a little rust on the bottom, but the rest is aluminum, and it works fine.
I bought those rubber stoppers at the auto store, about 2 bucks each, and plugged all the holes. It's a 3 part system. First is like an acid..and cleans it.. I also put in muriatic acid, and the inside of the tank looked like new shiney metal. rinsed good with a hose...and then some drying agent...which soaked up all the water...blew it out good with air......plugged all lthe holes.....taped over the small holes..and poured in the kreem......slosh the stuff iniside the tank for about an hour..make sure it covers everything, and then open it to dry....... I let mine dry for 3 days, and when I shine a light in it now......it is soooooo clean..... I don't see any problems with this stuff at all. That's my tank story.

Dave

Pooka · #9 12-19-2008, 08:53 AM

Removing one of these tanks is really pretty easy. Just drain the gas, let itsit with the cas cap off for a day or so to allow it to vapor off and then just take it out. You will notice that it is heavier than it looks, and can be rather clumsy to handle until it is out from under the car.

Putting it back in is the hard part. This was a two man job at the factory and the car was up in the air when it was done. I suspect you do not have a lift, so plan on finding some help during the install phase.

It is not just lifting it into place; it is also the lining it up like it was. When inserting the bolts just put them in enough to hold it up there, then adjust the tank's position, tighten, adjust... Repeat as necessary.

I would recommend having a radiator shop look at this and maybe let them do any repair job that is necessary. I know some of the popular tank sealers from the 1980's would disolve when gasoline from the 2000's was put into them because the chemical used in the sealer was not compatable with Ethenol.

If your tank is really shot then why not relace it with a used one? These cars are in the wrecking yards here and there and cars from the Southwest normally have tanks that are pretty clean.

Pooka

ja17 · #10 12-19-2008, 06:27 PM

Hello,

It is a bit more complex than you imagine, however it is quite do-able with just some good information. Be sure to read this thread for all the information http://www.sl113.org/forums/index.php?topic=1712.0

Your tank has the same inner workings as these W113 cars.

take care

mbgingerbread · #11 12-19-2008, 10:19 PM

Hi, Ja17;
I have bookmarked the site you have above. This is a comprehensive approach to cleaning the tank!-thank you..

I drained the fuel from the tank today-there was a little more gas in there so it was kind of messy-fortunately the wind picked up and I had the air at my back to help clear the air. I replaced the fuel screen at the tank early on-not much to report; however, it is obvious that the posts here will clear up any issues inside the flower pot and or the return and feed.
I must admit that I went to some trouble figuring out how to get the filter loose the first time. This go round I saw a 13/16 spark plug socket in my tool chest with a 7/8 end-you know when a crescent wrench will fit the end for certain removal tasks. I looked at this spark plug socket and realised that the end would fit into the screen head and then ( drumroll

) I put a short 3/8 extension up into the socket body where it's end seated in the same end as you would put an extension normally. It was a simple matter of attaching a 3/8 ratchet to the extension and putting the 7/8 spark plug socket into the screen filter socket head. Voila!-no welding.
My goal is to have every part of the fuel system checked out, cleaned and free to let the gas go where it is supposed to go.
I did not have any designs on coating the inside of my tank. If the upcomomg work fails to work I will probably take another route.
MBG

Pooka · #12 12-20-2008, 01:05 PM

A poster on this site, MAF, has some questions about a 6.3 part he found in a wrecking yard. You have a question about a gas tank from what might be the same body type. I say that because I think the gas tanks are different. I think the 6.3 tank holds more but might bolt right into your car.

Perhaps he could check out the tank for you and you two could work out something?

It might be that when you take out your tank it will be totally clean inside. I have seen this even from cars that have been sitting for many years.

Just a suggestion.

Pooka

mbgingerbread · #13 12-20-2008, 05:49 PM

Thanks, Pooka..
I have changed the fuel filter at the injection pump a couple of times-I know that there is a fuel system problem because the filter has been dirty each time. As far as the tank goes it looks good from the outside-the original coating is still there although not knowing the PO's to any extent I may have a newer tank or a good used one. I am taking it off to be sure that it is clean. I will take Todd's advice and run a piece of wire thru all the fuel lines to clean them.I will carefully inspect the flower pot and carefully run a wire or maybe a gun cleaning rod to check the feed and return lines in the tank. Once I have flushed everything and I am satisfied that it's all clean then I will put the whole system back together again.
I also intend to replace the rubber hose between the injection pump and the filter as well as the injection pump return hose. I will then change the filter again, bleed the lines and see if I can get the engine to stay alive longer than it has up to now.
If I find any gross violations of the tank I will look for another tank on the MB parts circuit....
By the way when I was draining the tank there was quite alot of frog eyes as we call them in the trade and stuff which just shouldn't be in a gas tank..
Thanks again

el sea · #14 12-20-2008, 09:13 PM

We clean fuel tanks without the removal of the tank. The process is very simply, we agitate what maybe resting on the bottom of the tank with a high velocity flow but being sure not to pressurize the tank. Once the cruddy stuff is subspended we filter your fuel through our filtration unit. Unless we find water or bad fuel you have no loss of fuel. We look for clean fuel and a healthy tank. With the introduction of ethanol we are see more and more problematic issues with the gas and with the bio-diesel blends more issues. My website will give more detail of the practice.

Luther

mbgingerbread · #15 12-20-2008, 10:36 PM

Luther;
I couldn't help but think that the simple way to clean the tank would be to introduce a pressure stream into the tank from the fuel sender opening. I can reach the two lines which are integral to the flower pot as it is called in this gas tank and I should be able to determine the cleanliness of the tank by what comes out of the drain.
When you mention the fact that you do not pressure the tank, am I to assume that your process involves something similar to mine except you use gas instead of water and have a collection system and filter in order to replenish the fuel you pump out?
In the meantime I will visit the site you suggest. How would I access this site?
Thank you...