Removed tank...help!, 1982 300D - PeachParts Mercedes-Benz Forum

300DPETE · #1 01-16-2006, 04:53 AM

1982 300D

Hi, guys.

I removed my tank today and took a good look inside. Looks a lot cleaner than the used tank I picked up last week (looks like I have a spare until I get this all straightened out).

It also occured to me that the big flakes of rust I saw in the prefilter could not have gotten past the fuel strainer, meaning that they couldn't have come from the tank. So, I'm starting to think that I need to replace the hard fuel line if that's the culprit instead of the tank....how hard is this to replace, and is it one line going all the way from the engine compartment to the tank? Is it all metal (sort of looks like hard plastic to me at the ends).

Thanks,

Pete.

biopete · #2 01-16-2006, 06:35 AM

Quote:

Originally Posted by 300DPETE

1982 300D

Hi, guys.

I removed my tank today and took a good look inside. Looks a lot cleaner than the used tank I picked up last week (looks like I have a spare until I get this all straightened out).

It also occured to me that the big flakes of rust I saw in the prefilter could not have gotten past the fuel strainer, meaning that they couldn't have come from the tank.

Thanks,

Pete.

Are you sure it was rust in inline filter ? I thought these fuel lines were alluminum and hard plastic. Is it possible it was just some deposits that got loosened up ?

t walgamuth · #3 01-16-2006, 07:49 AM

are steel! for sure. aluminum is not strong enough. yes, you can buy fuel lines. they come in sections of maybe five feet or so in length. they have to be hand bent like brake lines. this is not difficult. some care is needed to avoid crimping them. i would look for the problem. it will most likeliy be a place where there is a clamp or where they enter the body structure as these places can collect debris and rust will form. once the place is found you can replace the section that is bad.

i havent actually done this but i believe it is a general description that is pretty close.

tom w

sokoloff · #4 01-16-2006, 09:05 AM

Check in the area where the lines disappear under/over the rear trailing arm on the driver's side. That's the area that typically rusts away. Look for any seepage or even a puddle of fluid on the garage floor. You might be able to get away with replacing just a section of the line with a rubber line. Did mine over five years ago and it is holding up just fine. Sure is a lot easier than replacing the entire line too.

Len

300DPETE · #5 01-16-2006, 10:16 AM

Quote:

Originally Posted by sokoloff

Check in the area where the lines disappear under/over the rear trailing arm on the driver's side. That's the area that typically rusts away. Look for any seepage or even a puddle of fluid on the garage floor. You might be able to get away with replacing just a section of the line with a rubber line. Did mine over five years ago and it is holding up just fine. Sure is a lot easier than replacing the entire line too.

Len

I have to interject a dumb question here...

What's the rear trailing arm?

Also, what line is the return line of the two lines coming out of the driver's side of the tank?

TheDon · #6 01-16-2006, 10:19 AM

about 1600$ if you break it... its the very big piece of steel that is holding the suspension and the wheel and that to the body..

kmaysob · #7 01-16-2006, 10:23 AM

Quote:

Originally Posted by 300DPETE

I have to interject a dumb question here...

What's the rear trailing arm?

Also, what line is the return line of the two lines coming out of the driver's side of the tank?

the trailing arms are what the wheels are attached to in this pic. (thanks for the pic whunter)

300DPETE · #8 01-16-2006, 11:53 AM

I checked the hard lines...they look good from the outside...no rust that I can see leading me to a section to replace....bummer.

I also found some rust in the tank...I noticed that there was a line of fungus inside (somehow treatments didn't kill it) going along the weld at the bottom on the side of the tank facing into the trunk on the bottom. I took a paper towel and attached it to a pole and ran it along this line of fungus. I pulled up a layer of slime that had little specks of red in it. I then checked inside the tank and it was clean along the weld line I had just wiped free of fungus.

So, my question is...is a little bit of rust (small enough that I can't see it after wiping it off) a major issue? The reason I ask is that I called a radiator shop, and they said it would cost $60 to clean the tank (which is already pretty clean) and "you don't want to know" to have it acid dipped to get rid of any rust.

What do you guys think?

dieseldiehard · #9 01-16-2006, 12:04 PM

You could probably find a used tank somewhere at less than the cost for cleaning the old tank.
If its only a line around the tank, not a wide band, I'd live with it and change filters until its diminished. If the bottom of the tank is rusty that's a different matter.
I had a tank from a 115 chassis (gasser) coated and it has held up fine, it cost $75 for that job here on the Left Coast.

300DPETE · #10 01-16-2006, 12:09 PM

Quote:

Originally Posted by dieseldiehard

You could probably find a used tank somewhere at less than the cost for cleaning the old tank.
If its only a line around the tank, not a wide band, I'd live with it and change filters until its diminished. If the bottom of the tank is rusty that's a different matter.
I had a tank from a 115 chassis (gasser) coated and it has held up fine, it cost $75 for that job here on the Left Coast.

I did get a used tank....and it has signs of rust to!!! (not much, but still, ugh). Someone stop poking my vodoo doll. I'm going to stick with my original tank as it looks a lot cleaner inside.

300DPETE · #11 01-16-2006, 12:41 PM

I just spoke with an indy who said that he doubts it's the hard lines. I asked him about how it would be possible for large flakes of rust to get past the tank strainer and he mentioned something about a slot at the base of the strainer that the larger pieces of rust (maybe half the size of lincoln's head on a penny) could get through.

Any thoughts?

Pete.

dieseldiehard · #12 01-16-2006, 12:57 PM

Ah, yes it's possible that the area after the strainer is indeed rusting, its about a penny in size and certainly at the bottom of the tank, that's where any water will settle out.
I'd just change the prefilter and run with it to see if it comes back, but you already have the tank out I don't know if its possible to remove the large strainer holder fitting or not, I've never seen one removed but it should be possible, it was put on the tank somehow. The TD (wagon) tank is relatively shallow and its easy to see down into from the hole where the level sensor goes. The sedan tank is not so easy because its a taller tank. A borescope would be nice, huh?

I doubt that rusting inside the fuel lines woud provide flaking either. A rusty fuel line usually results in a leak where fuel is able to pass thru the wall.

You can also have the problem on a rusty supply line where tiny bubbles of air will be pulled in when the level in the tank drops below approx. one quarter full, and then engine loses power. When filling the tank the problem goes away because the gravity fed pressure overcomes the vacuum from the lift pump, it's an odd problem that a few people have seen, myself included.

300DPETE · #13 01-16-2006, 01:10 PM

Quote:

Originally Posted by dieseldiehard

You can also have the problem on a rusty supply line where tiny bubbles of air will be pulled in when the level in the tank drops below approx. one quarter full, and then engine loses power. When filling the tank the problem goes away because the gravity fed pressure overcomes the vacuum from the lift pump, it's an odd problem that a few people have seen, myself included.

Can you explain this one to me a little more...that's what's happening to me...if I don't have more than a quarter of a tank of fuel it stalls out....but I don't see any evidence of rust (at least on the outside) or leaks with the hard lines.

Wouldn't I notice this by seeing air bubbles in the pre-filter...

t walgamuth · #14 01-16-2006, 01:29 PM

yes

tom w

dieseldiehard · #15 01-16-2006, 01:36 PM

Quote:

Originally Posted by 300DPETE

Can you explain this one to me a little more...that's what's happening to me...if I don't have more than a quarter of a tank of fuel it stalls out....but I don't see any evidence of rust (at least on the outside) or leaks with the hard lines.

Wouldn't I notice this by seeing air bubbles in the pre-filter...

Stalls out? I have never heard of that happening, and yes I would think you will see a huge air bubble in the pre-filter if it stalls out.
Incidentally to check for this place a rubber glove over the neck in the fuel tank as a gasket, and apply a few psi air thru it. Use no more than that! While someone looks for dripping fuel on the supply line.