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MG MGB Technical - charcoal canisters

dont now when they were replaced or if they were ever replaced on my 79b. dont have any pollution controls on it except canisters and thats it. I have a weber dgv carb. I do smell some gas on the trunk sometimes? I guess I am wondering if I should spend 180 bucks to replace them. Thanks , Doug
dd doug46chief

There are several stories on the web about replacing the charcoal - get from aquarium supply place, not hard.

Fuel vapour in boot is more likely a bad hose to the separator. Can saw the ferrules off and replace hose with regular fuel hose while saving fittings.

Or filler hose loose or bad.

Or, rusted out tank top is also common.
Look for signs of gas trickling down the sides when full - leaves marks but usually not wet.

FR Millmore

thanks for the info, didnt know the canisters came apart to add the charcoal. Doug
dd doug46chief

I removed the canisters and found rotted springs in bottom of both. I also found in the secondary canister a metal screen at the top. I have tried to find screen but no one seems to have it. Is the screen needed or can i just fill it up and put the bottom plastic screen in and leave it at that? I did buy a mesh from the pet store used in the filters for fish, but I think it might get clogged from the venting .any thoughts? thanks , doug
dd doug46chief

I have not seen the inside of one of those for a very long time, don't recall what the screen is or does. If it is retaining the charcoal, you need it or a functional substitute. Window screen in fibreglass or metal, colanders/strainers from the cookware section of the local cheap crap store, hardware cloth from huilder's supply, toys for sandbox & beach, plastic mesh for sewing projects from cheap crap or Joann's Sewing * Craft Supply etc.
"Stuff with holes in"

FR Millmore

thanks, I didnt think of the cheap crap store stuff, but sounds like a good start. Doug
dd doug46chief


I have been using the aquarium charcoal in our B/GT canister for many years. Be sure to only buy the pure charcoal (small black stone) granule type. I also cut a (small) galvanized steel mesh screen to replace the original screens. Purolator make a circular (gauze type) filter/breather material that you can fit in the base that works well.

The link below may help.


Larry C. '74 B/GT & '69 midget
Larry C '69 Midget

Doug. A great deal of information on this subject in the archives. It was covered, in great depth, several years ago.

Les Bengtson

This thread was discussed between 10/07/2012 and 12/07/2012

MG MGB Technical index

This thread is from the archive. The Live MG MGB Technical BBS is active now.