Gas separator (Evaporation Emission System)

[G B.]

A small black plastic canister is mounted high on the driver's end of a 1972 gas tank. The 1983 GM parts book calls it a "separator" in the Evaporation Emission System for all 1970 - '74 Corvettes. I assume its function is to route liquid gasoline back into the tank after it has sloshed into the EES vent tube. I have a customer with a cracked separator that leaks gas onto one muffler when he drives with a full tank. This is not an acceptable situation, but I can't find a replacement separator.

I believe the GM service part, (#7028035), was discontinued in 1986. I haven't found any aftermarket source. Can anyone recommend an available replacement that will bolt up? I've checked Dr. Rebuild, Paragon, and eBay. None of these sources list anything that will work.

[Joe L.]

Re: Gas separator (Evaporation Emission System)

Jerry----

The piece to which you are referring was GM #7028035. It was discontinued in October, 1986 without supercession. As far as I know there is no replacement available for this part, either as a "reproduction" or in the world of aftermarket replacement parts. This particular piece was Corvette-only which limits the interest in the aftermarket supplying a replacement. I might suggest trying to adapt a passenger car seperator if one were still available. However, none are; they're all discontinued, too. So, that option is foreclosed.

These seperators are going to get to be a real problem as I've said on numerous previous occasions. They're made of plastic and they're constantly exposed to gasoline. That means that they WILL degrade over time. No common plastic material is 100% impervious to gasoline. I believe that these seperators were made of polyethylene or polypropylene which is very resistent to gasoline, but it is deteriorated eventually.

In a way I'm surprised that GM discontinued this piece. It is an important safety component as well as an emissions control component. However, it may be its safety implications that got it discontinued. If GM sold you one of these and soon thereafter a 16 wheel dumptruck rear-ended you causing a fire and explosion, perhaps GM would be exposed to the world of "vicarious liability". So, maybe they decided they don't want that liability so they don't sell the part anymore.

By the way, I don't even have any of these in the collection. Since I don't own a 70-74, I never took an interest in collecting it while they were still available. By the time I took an avid interest in collecting parts not applicable to 69s, these were long-gone. I've never seen an NOS example for sale, either, since then.

[Joe L.]

Re: Gas separator (Evaporation Emission System)

Jerry----

The piece to which you are referring was GM #7028035. It was discontinued in October, 1986 without supercession. As far as I know there is no replacement available for this part, either as a "reproduction" or in the world of aftermarket replacement parts. This particular piece was Corvette-only which limits the interest in the aftermarket supplying a replacement. I might suggest trying to adapt a passenger car seperator if one were still available. However, none are; they're all discontinued, too. So, that option is foreclosed.

These seperators are going to get to be a real problem as I've said on numerous previous occasions. They're made of plastic and they're constantly exposed to gasoline. That means that they WILL degrade over time. No common plastic material is 100% impervious to gasoline. I believe that these seperators were made of polyethylene or polypropylene which is very resistent to gasoline, but it is deteriorated eventually.

In a way I'm surprised that GM discontinued this piece. It is an important safety component as well as an emissions control component. However, it may be its safety implications that got it discontinued. If GM sold you one of these and soon thereafter a 16 wheel dumptruck rear-ended you causing a fire and explosion, perhaps GM would be exposed to the world of "vicarious liability". So, maybe they decided they don't want that liability so they don't sell the part anymore.

By the way, I don't even have any of these in the collection. Since I don't own a 70-74, I never took an interest in collecting it while they were still available. By the time I took an avid interest in collecting parts not applicable to 69s, these were long-gone. I've never seen an NOS example for sale, either, since then.

[G B.]

Just shoot me

Thanks for the info, Joe. I guess I'll have to fabricate a replacement out of aluminum or stainless. It seems kinda pointless to buy and install a used separator from another old Corvette.

[G B.]

Just shoot me

Thanks for the info, Joe. I guess I'll have to fabricate a replacement out of aluminum or stainless. It seems kinda pointless to buy and install a used separator from another old Corvette.

[Joe L.]

Re: Just shoot me

Jerry-----

Yes, that's what I've always thought, too. A used example of one of these seperators might be just a little better than the one replaced and likely has only a little life left in it. This is a piece that "cries out" for a restoration source. Unfortunately, product libaility concerns might just be the "fly-in-the-ointment" as far as reproductions go.

I believe that there is a "check valve" in this part that prevents fuel spillage in the event of a "roll over" or certain other types of accidents.

[Joe L.]

Re: Just shoot me

Jerry-----

Yes, that's what I've always thought, too. A used example of one of these seperators might be just a little better than the one replaced and likely has only a little life left in it. This is a piece that "cries out" for a restoration source. Unfortunately, product libaility concerns might just be the "fly-in-the-ointment" as far as reproductions go.

I believe that there is a "check valve" in this part that prevents fuel spillage in the event of a "roll over" or certain other types of accidents.