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How does one replace the filter in the evap canister on a '72 Supreme? The CSM and the ASM don't go into detail about the procedure. Here are pics of my canister and the replacement filter. From what I can tell, the canister doesn't come apart.
Also, what's the port on the filter used for? That's not shown in the CSM or the ASM either.
First filter like that I've seen. The ones I've used came as filter element only.
The opening in the new piece is the canister's outside air intake. You notice the original's filter is pretty much open to atmosphere.
Pry the fiberglass elements out of both pieces, then work the new filter into the original canister thru the bottom opening. Problem solved.
Newer production OE filters are made of open-cell foam instead of fiberglass. I don't like them as well as the fiberglass but the glass ones aren't as easy to find now, even aftermarket.
Does the cap assembly fit into the bottom of the canister? It should just snap in. If that’s the case, just pull the yellow filter out of the canister. Easier than replacing the canister… it should look like this on the bottom:
and from underneath the car, the cone should line up with the hole in the inner fender liner.
Hi Dave - The bottom of my '71 CS canister looks same as your 1st image. I simply remove the canister, turn it upside down (charcoal settles to top), remove the filter from the bottom of canister by pulling out, it's about 1/2" thick (the filter is more or less like a 3M abrasive scratch pad), then insert a new filter. You can buy absorbent pads at any of the big box stores - most are a square shape. Just cut a circle and insert the new absorbent pad in the bottom, turn canister right-side up and done. You could change charcoal as well if you want.
Does the cap assembly fit into the bottom of the canister? It should just snap in. If that’s the case, just pull the yellow filter out of the canister. Easier than replacing the canister… it should look like this on the bottom:
and from underneath the car, the cone should line up with the hole in the inner fender liner.
Here are a couple images of a different type of filter material which may or may not have been the OEM type material - who knows. At any rate....good luck!
Does the cap assembly fit into the bottom of the canister? It should just snap in. If that’s the case, just pull the yellow filter out of the canister. Easier than replacing the canister… it should look like this on the bottom:
and from underneath the car, the cone should line up with the hole in the inner fender liner.
Does the port on the bottom just vent into the air?
So I just did some checking and it seems the new one is a bit smaller in diameter than the one that's in the car, because when I put the new one in, I tightened the clamp as far as it would go, and the canister was still a little loose. Could it be that the filter cap adds some height and thus not allowing the canister to fully seat and that's why it's not fully tight?
The bottom of YOUR canister is the 1st image in this post - correct? Why are you attempting to install part #7021739 into your canister? It is not the correct filter.
I was able to snap the housing onto the canister with no issues. I'm just not sure why the new canister doesn't fit as tigjt as the old one.
Possibly because you have the incorrect fuel canister retainer?
NOTE: Chevrolet manufactured two different sizes of fuel canister retainers. You certain you have an Oldsmobile fuel canister retainer?
I have no idea what fuel canister retainer you have installed, but note the following two different part numbers for two different fuel canister retainers and the applications for the part #7021739 filter w/ drain cap.
Here's a nice new GM# 7026014 Filter NOS (the one designed for your canister). Unfortunately, it's for a Corvette - just kidding! At least they have the years of application listed correctly (as I identified in the Oldsmobile Parts Catalog above).
The bottom of YOUR canister is the 1st image in this post - correct? Why are you attempting to install part #7021739 into your canister? It is not the correct filter.
Norm, I wasn't trying to put that filter onto my canister. I bought another canister that came with that filter under the assumption that all canisters were created equal, but apparently that's not the case. And yes, the first pic above showing the bottom of the canister is actually mine. RocketRaider's response in #2 above pretty much sums it up in my caae..."the bottom of the filter is open to the atmosphere." This tells me that mine is correct, so I'm leaving it alone, besides, as you can see, my filter is still in pretty decent shape.
Possibly because you have the incorrect fuel canister retainer?
NOTE: Chevrolet manufactured two different sizes of fuel canister retainers. You certain you have an Oldsmobile fuel canister retainer?
I have no idea what fuel canister retainer you have installed, but note the following two different part numbers for two different fuel canister retainers and the applications for the part #7021739 filter w/ drain cap.
Norm, I have no reason to suspect my bracket is not original, but your pic clearly shows that there were different brackets for different canisters. This would explain why the one I purchased didn't fit as tight as the one that was in the car. Who knew? As the saying goes, you learn something new every day.
Norm, I have no reason to suspect my bracket is not original, but your pic clearly shows that there were different brackets for different canisters. This would explain why the one I purchased didn't fit as tight as the one that was in the car. Who knew? As the saying goes, you learn something new every day.
I'm not trying to confuse you but note the parts I referenced above in that image is from a Chevrolet parts book. As noted in the Oldsmobile parts book i only looked up the filters for you NOT the canister bracket, but I did provide you a CO link of the type bracket you should have in your car - Post #17
Last edited by Vintage Chief; Mar 10, 2023 at 07:55 PM.
I'm not trying to confuse you but note the parts I referenced above in that image is from a Chevrolet parts book. As noted in the Oldsmobile parts book i only looked up the filters for you NOT the canister bracket, but I did provide you a CO link of the type bracket you should have in your car - Post #17
It's kinda hard to tell from that pic what it should actually look like, but I'm gonna take a pic of mine tomorrow and post it here. In the meantime, is it agreed that the canister and filter I bought are not correct for my car?
The canister (7028131) is the correct canister. The filter (7021739) is NOT the correct filter for that canister. It is correct for select Chevrolets and a 1973 Oldsmobile 6 cyl. engine. Part #7026014 (called an element pkg) is the correct filter for the (7028131) canister. The correct bracket for the canister is listed in Post #17 - part #408174.
