| Charcoal canister filter maintenance write up/reminder [message #278017] |
Mon, 18 May 2015 21:15  |
Tilerpep
Messages: 404
Registered: June 2013
Location: Raleigh, NC
Karma: 7
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Still had some gas odors. Got a new gas cap. And it proved that pressure was building in the tank with a good blow when I took it off.
I had checked the fuel vapor separator (above driver rear tires) when I first got the coach, it checked ok and other things took precedence.
After new cap, decided to check lines to the front. The vent line blew clear to the gas filler neck, good.
Nothing through the line forward from fuel vapor separator. Unhooked it from hard line at driver front tire. Blew rubber line out, full of water (not gas). On to the hard line that crosses behind engine. Nothing passing. Unhooked canister side, used a coat hanger and compressed air and got it free flowing. Getting the canister out of the mounting bracket was a bear - the canister was so grimed in it was royally stuck. You can't remove the bracket unless the canister is out. Hours of tedium to not break anything and all was disassembled.
I think this filter from the bottom was way past service life! Maybe original, who knows.
If you haven't checked your system, move some air through the lines and visually inspect the filter underneath. You can see it without removing anything, but to change it, you have to get the canister out of the holder. I didn't use a Fram BA357 filter, but Oreillys cross listed it for less than $3.
1975 Glenbrook, 1978 Royale rear bath
Raleigh, NC
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| Re: Charcoal canister filter maintenance write up/reminder [message #278063 is a reply to message #278017] |
Tue, 19 May 2015 22:22  |
Tilerpep
Messages: 404
Registered: June 2013
Location: Raleigh, NC
Karma: 7
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You could definitely pull out the old with a pair of needle nose pliers, but putting it back in through the flared metal air hole would be tough. My canister had a plastic bar across the width of the open end to retain the filter. Getting the filter positioned under that bar would be tricky. This is one of those jobs that if everything was new and worked as designed it would take five minutes. Hopefully your canister will just pull out of the metal bracket after releasing the one tension screw. If so, easy. If not, you have to decide if you will break the canister (time and money for new one) or go slow and work it out (time and effort for old one). I have taken two local trips and partial fill up since getting the lines open and new filter. No gas smell so far.
1975 Glenbrook, 1978 Royale rear bath
Raleigh, NC
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| Re: Charcoal canister filter maintenance write up/reminder [message #278077 is a reply to message #278017] |
Wed, 20 May 2015 08:37 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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This post sent me looking at mine. I suspect I've found a LOT of the stumbling trouble. Mine has two, so I suppose it was set to CA spec. Anyway, the hoses came apart in my hands. So, today both of the canisters come out, get cleaned, and new hoses fitted and the crossover pi[pr gets cleaned out.
--johnny
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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| Re: [GMCnet] Charcoal canister filter maintenance write up/reminder [message #278078 is a reply to message #278077] |
Wed, 20 May 2015 09:19 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Johnny, if you have two canisters, Only one handles the fuel tank vent.
The other handles carb float bowl venting. The canisters differ a bit from
the 49 states ones in that they have vacuum controlled inlet valves that
depend upon vacuum from the engine before they can breathe. So if you check
them for flow, apply vacuum before you test or you will think that they are
restricted or plugged when they are not. Just a tip from one who has been
there/done that, and studied and learned a bit about canisters.
Jim Hupy
Salem, Or
78 GMC 403 49 states optioned.
On May 20, 2015 6:38 AM, "Johnny Bridges" wrote:
> This post sent me looking at mine. I suspect I've found a LOT of the
> stumbling trouble. Mine has two, so I suppose it was set to CA spec.
> Anyway,
> the hoses came apart in my hands. So, today both of the canisters come
> out, get cleaned, and new hoses fitted and the crossover pi[pr gets cleaned
> out.
>
> --johnny
>
> --
> '76 23' transmode Norris upfit
> Braselton, Ga.
>
> "Sometimes I wonder what tomorrow's gonna bring when I think about my
> dirty life and times" --Warren Zevon
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
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| Re: [GMCnet] Charcoal canister filter maintenance write up/reminder [message #278080 is a reply to message #278078] |
Wed, 20 May 2015 10:43 |
midlf
Messages: 2212
Registered: July 2007
Location: SE Wisc. (Palmyra)
Karma: 1
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James Hupy wrote on Wed, 20 May 2015 09:19Johnny, if you have two canisters, Only one handles the fuel tank vent.
The other handles carb float bowl venting. The canisters differ a bit from
the 49 states ones in that they have vacuum controlled inlet valves that
depend upon vacuum from the engine before they can breathe.
This is one of those items where the year of your GMC makes a BIG difference. On 73-74 coaches the CA emissions option uses two canisters but they are connected in series for double the capacity. There are no vacuum valves and no carb float bowl venting. I'm not sure what year this change for the CA emissions but the parts book can tell you.
Steve Southworth
1974 Glacier TZE064V100150 (for workin on)
1975 Transmode TZE365V100394 (parts & spares)
Palmyra WI
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| Re: Charcoal canister filter maintenance write up/reminder [message #278087 is a reply to message #278017] |
Wed, 20 May 2015 15:38 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Senior Member |
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This pair are meant to hook in series. The upper has a hose fitting on the bottom, the lower has the bottom opening of the single version. The upper looks like it was made from a lower by putting a solid plastic bottom with one hose nipple on. They're hooked in series. I can chase out the ends of the broken lines. Both canisters have CARB and TANK inlets on top. I have the maintenance manual and the '76 supplement. Merely time consuming.
--johnny
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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