evaporative fuel canister lines

[Ferrolanoman]

This morning after a short drive I discovered that one of the two small plastic lines connecting the evaporative fuel canister to the gas tank in my '70 280SL was leaking gas onto the trunk floor, enough so that gas was dripping onto the pavement while the engine was idling as I was ready to put the car back in the garage. So what can I do to cure the problem:
Buy a replacement canister with the lines attached just because one of the lines has leak where it connects to the canister for $265 (BUDS)? Seems like an excessive and wasteful answer.
Repair the small crack in the line, but how?
By-pass the whole evaporative canister system, but how?
Finally, do I have to lower/remove the gas tank in order to access the two gas tank outlets where the two lines connect?
From what I've read this is not an uncommon problem but I have very little inkling as to what to do about it. Any and all advice from those of you who've experienced this issue and how you solved will be very much appreciated.
Ricardo

[Pawel66]

if the crack is small, I would try to fix it with epoxy. Just sand down with fine sand paper the crack area and use some degreaser. If that does not work, second stage is to glue in a piece of pipe of appropriate diameter in the expansion tank and use the intermediate piece of hose (take a look at various pictures in the Technical manual and numerous threads you can find on this topic). The appropriate diameter pipe a lot of people here used was a piece of metal ballpen refill (the thicker one).

Removing the expansion tank is not difficult. If you have to remove it with lines, you just need to unscrew the fuel filler cover in the trunk. The expansion canister is fixed to the side panel with two clips. You may have the third clip holding the lines.

[Kevkeller]

I have new line I can sell at cost if you need.  PM me.

Kevin

[Ferrolanoman]

Thanks for the replies.
No problem removing the canister, it's already detached from the clips, I was referring to worst case scenario--what if I have to replace the lines at the top of the gas tank? Does the gas tank have to be lowered or removed?
Main problem is that the one broken/perforated line is damaged next to the nipple attaching point (flexible rubber I'd guess) to the canister so that the suggested sleeve repair is somewhat more difficult than if the break were further along the line. By the same token, can I cut the line where it's leaking and reattach it? I'd only be losing about 1/4".
Any particular epoxy? JB WELD is my favorite but will it last if in frequent contact with fuel? Is silicone paste out of a tube better?
I will peruse the tech manual and tips to further reassure myself before diving in.
PS: All of this is a result of my enthusiasm at finding a local gas station selling ethanol-free gas last fall and subsequently (over)filling the tank. I suppose the break in the line was there but no leak was detected since I never bothered to keep more than 1/2 tank of fuel to keep it fresh.
Hopefully I can repair rather than replace, although I'm glad someone can supply me with a new line.

[Pawel66]

No, you do not need to do anything with the gas tank. Just unscrew the filler cover (some 12 or 14 small screws) and you will see the nipples and the lines underneath.

I am not sure which type of expansion tank you have. I thought you had the newest one, where the lines are coming out directly from the tank. The older type had nipple in the expansion tank, connecting short hose and then metal line to gas tank.

And I am not sure which line is broken - I assumed the line in the newest type of expantion tank.

In the newest type of expansion tank breaking of lines happens very often. If you cannot glue a small crack, you can cut the nipple flat, drill appropriate hole and fit in a new nipple (a short small pipe). Or if the broken nipple is long enough, you can slide connecting hose on it or slide a small pipe on it. You certainly need to use small clamps on the connecting hose.

Take a look at Technical Manual.

But maybe I misunderstood what is broken and in which type of tank. Picture would help.

[Ferrolanoman]

I have the newest (car is 1970) vapor canister, flat rectangular, located on driver's side, one rubber line with round valve coming out of the top of canister, two hard plastic lines coming out of bottom of canister. It is one of these small diameter plastic lines that is broken, very near or at the rubber nipple which connects it to the canister.

[Pawel66]

Ok, sorry, you have the enclosed system then with the pipes going through the trunk floor.

I think the ideas on repair main remain similar, but I cannot help with what is required on the gas tank to fix it as I am not sure how it is connected there. Sorry.

[Ferrolanoman]

Can I bypass the canister by 1) capping the two plastic lines and 2) simply using a vented gas cap and thus preventing a vacuum (vapor) lock or--worse case scenario--the collapse of the fuel tank? I drive the car only a couple of hundred miles per year. It would simplify matters for me considerably.

[kampala]

This type of rectangular expansion tank seems to be available from Mercedes for less than $120 US$ from the online Mercedes dealers (list price is higher).   This obviously only works if you know for sure the leak is at the tank.

Part number: 115-471-16-68

Sometimes the leak is in the line running under the car towards the front - that's a different matter.   Maybe others can comment on just adding a vented cap.

[Ferrolanoman]

I've gone ahead and sleeved the damaged two plastic lines running from the canister to the gas tank with 1/8" fuel line securing them with small screw clamps. All's well--for now. I'm not sure what I will do for a long term solution all the while keeping an eye on the repair. Frankly, I am very disappointed in how M-B chose to deal with this emissions issue (the recovery of fumes) since it seems to me a poorly executed afterthought not meant to be either durable, reliable or even safe. My trunk floor was flooded with gasoline and only by sheer circumstance did I discover it. As might be expected, with the top down there was no smell of gas. It was only because I saw drops of gas on my driveway after returning from my short trip that I opened the trunk and found the scary source. Equally disappointing is the method used to secure (?) the flat rectangular canister to the left side of the trunk--a cheap, brittle, unattached piece of CARDBOARD--that disintegrated as I tried to carefully tuck it away into position. Truly unworthy of German quality standards and the engineering we expect from M-B as I'm sure others have already found out.

[Shvegel]

You can access the lines at the tank by removing the cover over the gas tank filler neck inside the trunk.

Here is the new tubing:
https://www.amazon.com/gp/aw/d/B0092KVJEK?psc=1&ref=yo_pop_mb_pd_title

[Mike K]

I had a number of similar issues on my '71 280SL. There was a blockage on one of the small fuel lines that runs from the filler neck to the venting tank. There was also an issue of pressure build up in the tank, every time I opened the filler cap. I think this was related to the blocked venting tank lines.

Also picked up a leak in one of the lines near the venting tank.
I removed the venting tank, cut the lines which are plastic-welded to the venting tank, cleared everything out with an air compressor and spliced in new fuel lines. I also replaced the grommet which is under the car. No issues since.

Best,
Mike

[Ferrolanoman]

Is the cardboard backing to which the canister attaches available at any of our vendors? I can't seem to find it. As I said above, mine literally disintegrated into smaller pieces every time I touched it--age, fumes, dryness, I assume.
Also, I still think that as little as we drive these cars, eliminating such an add-on system by installing a vented cap would be a reasonable answer unless it interferes with the fuel injection system.
Any constructive thoughts?

[mrfatboy]

The trunk panels are available through several vendors.  Look around. Here is one example.

http://www.authenticclassics.com/Mercedes-230SL-250SL-280SL-Left-Trunk-Liner-p/auth-003072.htm

Alternatively,  you can make your own.  The patterns are in the tech manual.

https://www.sl113.org/wiki/Restricted/UnderdashAndTrunkPanelTemplates

[Pawel66]

Ferrolanoman, I would drop the thinking of vented cup. Understanding that you may be a bit frustrated now, I would stay as much as possible with what the factory manufactured (due to the US law, by the way, on enclosing the evaporation system).

I would not be surprised that plastic or cardboard parts cracked a bit or fell apart after 50 years of being used. I am over 50 and I crack and fall apart here and there too...

I have replaced both of my trunk covers with MB original spares. They were ca $200 per piece in my geography. I decided to use MB spares whenever possible/available and visible. The new cardboard parts you get are very durable and fit nicely.

I see two part numbers for the trunk cover for US cars, depending on the VIN number (change as of chassis 11948) - perhaps because of slots pre-cut for holding the expansion tank on the left. I would call your US Classic Center (which I hear is just great in the US) and ask the gentleman there to check the part number, price and availability for you. You may also need some new clips or grommets.

I checked the availability of the one for later cars - it is available (at least here).

Fitting this trunk side cover is a physical exercise - do not be surprised you need to really push it in.

[Ferrolanoman]

Thank you for the latest suggestions. Now that I've been made aware of the piece's availability, as well as the pattern of same, I can rest easy and proceed accordingly.

[TEJOLX47]

Hi there,

Did you succeed on replacing the cover board for your fuel canister?
I think the templates provided are a little different from the one in my car. And I would like to replace it.
Cheers
Francisco

[Chris Long]

FYI my line snapped off close to the tank but found a solution that worked perfectly.

https://www.amazon.com/gp/aw/d/B07KLYB43N

[Pawel66]

I think this happens quite often, happened to me. There is a certain type of ball pen refills that can act nicely as a fixture to be glued into the evaporation tank - those thick metal ones.

[MikeSimon]

My car, a 1971 (model) , German spec does not have that tank. Wasn't that a California requirement only?

[Pawel66]

Does it have an evaporation tank on the left of the trunk? A bigger one.

I think nothing to do with California. Early cars - venting through the filler cup. Later cars (majority) small expansion tank. Late cars, I thought mainly US, but maybe not, larger tank on the left of the trunk, venting to the engine.

[Shvegel]

70-71 all US spec cars.  I had the same problem but fashioned a pair of special pliers to crimp new lines on to the tank.  I heat them up and squeeze them on to the tank nipple which melts the new lines on.  I don't recommend it as it is untested as of yet.

[MikeSimon]

No evaporation tank in mine. Late 71 model, as I said German car. California, for some time, has outlawed the ventilation of gasoline fumes from the tank into the atmosphere. Many manufacturers use a carbon can.