collapsed tank/charcoal canister failure

[bbarcher]

86 190E 2.3L

Hello, I was wondering about your experiences with the charcoal canister. I replaced the tank after a leak that failed to stay fixed. Then the replacement fuel tank did the same thing, and I realized that it was collapsing. I had tested the vent line with a vacuum pump, and it was not clogged. I blew through the vent valve in both directions. The vent valve seemed to work properly, building a bit of pressure then popping open.

So I thought the venting system was good, but it is not. So I decided that my vacuum pump test was inadequate. The only thing I could think was that the line was damaged or the charcoal canister was bad. I did not see any damage to the line. I looked for a used charcoal canister at the Pick-n-Pull, but found that it was leaking the charcoal pellets out pretty badly. They look like little pieces of mechanical pencil lead. So I didn't get that one. I took apart my car, and found a few grains of the charcoal in one of the ports.

Is it common for the charcoal bits to escape the canister? The one in the junkyard was a 1990, and had bits all up in the line going to the engine. I have heard of moisture causing residue to build up and clog the canisters, but I am just curious, should I go ahead and get a new vent valve as well as a new canister?

Both used tanks that I have bought so far were $100 each, so I wanted to check in and let you know of my travails. The car has been laid up more than I can afford, and my truck is crying out for some attention that I haven't been able to give it.

Since the only canister I could find at the junkyard was no good, I did some quick checks and found one from a BMW 3-series that I think will work nicely. It is a 2 port design with the open bottom for taking in vent air, unlike the Mercedes that takes in fresh air through a tube. And it is small enough to fit. I blew air into both canisters, and the BMW one flows much easier. The one on my car flows, but I believe it is partially clogged.

Let me know what you think. Thanks!