Snapped bolt, how to remove?

Ok. I wasn’t certain. I just don’t understand how dirt entered the charcoal canister on GM trucks if the charcoal canister is sealed. They even had a tsb to relocate the canister where it wouldn’t come into contact with as much dust.

The only way I can see to fix this involves a piece called a doubler. Basically you will need a piece of sheet metal or plastic, sheet metal will be better. You will have to remove the canister because it is unlikely you will have room to do this in the vehicle.

Cut out the area around the vent valve. The cut a piece of sheet metal a little larger than the cut out, about a 1/2" all the way around. It is important that the cut out is not perfectly round, square or rectangular would be best. The sheet metal is the doubler. Cut or drill out the mounting holes and the hole for the valve.

Line up the doubler with the cutout and drill a small hole that is the major size (outside thread dimension) of the bolts that you will use to mate these together, or the size of the pop rivet you will use. Pop rivet would be better if you have the equipment. Drill through both the doubler and the canister body. Put something the size of the hole you drilled through the hole to maintain alignment. Drill the opposite side and repeat. The drill all the rest of the holes (at least two more).

Remove the doubler, mount the vent valve to it. Then RTV the back side of the doubler and put it in position on the canister and pop rivet in place.

Alternative would be to drill all the holes in the doubler first to the major size of sheet metal screws, then use the doubler as a guide to drill pilot holes in the canister and follow abouve but using sheet metal screws instead of pop rivets.

Second alternative if the plastic body of the canister is not thick enough or too brittle for sheet metal screws would be to align the doubler to the canister body, drill pilot hole through the doubler and the canister body. Then drill out the holes on the canister body to the major size of the sheet metal screws. Mount the doubler first on the canister from the inside with a good layer of RTV for a sealant and fasten with the sheet metal screws. Then mount the valve. Instead of captive nuts, drill pilot holes and sheet metal screws to mount the valve.

You may want to use some RTV to seal the valve to the sheet metal if it is not flat enough for the gasket to seal by itself.

How about one of those fasteners that expands in a hole as you tighten the bolt - kind of like those rubber freeze plugs?

Or even those metal ones with the “spidery legs” in the center that expand outward … or the plastic ones used in drywall.

There’s gotta be a fastener for this case, but you gotta cut that one off first … and not damage the canister housing in the process. That sounds like a Dremel or cheaper Harbor Freight equivalent to me (maybe with a quality cutting wheel to avoid too much struggling)

Yeah like I said, Harbor Freight threaded insert tool. Or fashion a T nut with JB like I said. Something to get threads. Since it doesn’t appear the second bolt is crazy mandatory for the seal.

The doubler sounds like a lot of effort and drilling a larger hole in sheet metal might be an issue. When I was a kid, my neighbor’s dad fixed a hole in the block of my small engine like that. This was before aluminum welding was common or maybe it was cast iron back then. But he used a brass plate with a gasket and threaded small bolts to hold it in place. Worked fine to keep the oil in.

I’d completely remove the captive nut & broken bolt, cut both pieces off w/a hacksaw or dremmel w/cutoff disc. If the captive nut spins and prevents you from cutting it off, first curse a little, then JB Weld it so it won’t spin, wait 24 hours, then you should be able to cut it off. At this point you’d be left with an unthreaded hole to deal with. So JB Weld a new captive nut over that hole. Use enough JB weld so there will be no air leaks. Figure out a way clamp the nut on tight for the entire 24 hours it takes for the glue to set up. Now you should be able to attach the replacement solenoid, as if the problem never occurred. You could put a little gasket sealer on the bolt threads that go through that nut if you worry about it leaking.

This process will be easier if you remove the charcoal canister from the engine compartment and fix the captive nut problem on the bench.

I’m about to quit this conversation but just can’t help myself. Maybe I got the picture wrong but if you JB a nut on the outside of the canister, the solenoid flange will fit on top of the nut and not be against the canister. You’d have to get access to the inside of the canister, then you might as well use a Tee nut with a glob of JB or the thread insert. Won’t know till you cut the thing off and pull the solenoid to be able to feel inside but I gotta feeling though they have a big plastic molded gate that they pressed one of those brass thread inserts into. Then that would be a little tougher to deal with.

The existing captive nut is on the outside surface, right? Or are you saying it might be difficult to find a nut with the same thickness dimension as is on there now?

Thanks for the comments.
Keith: it is hard to follow the instructions since I have never seen this method before. Can you point me to an YouTube video that shows this process.
Bing: The canister must remain air tight. I cannot cut it to access inside. I cannot even remove the canister from the car, its fasteners are weak. The threaded insert tool may not be the best solution as it flares up and creates an uneven bulge. The whole is too small.
Rubber freeze plugs wont work.
There are 2 captive nuts. One you can see on the photos still attached to the stem of the head-broken bolt and there is another one inside the canister which has lost its anchor\moorings. Now the stem along with 2 captive nuts rotates freely but wont come out of the canister, something is holding them in the canister.

I think if I just really wanted to attach that thing to the charcoal canister, I’d sand the plastic parts where they mate, buy some epoxy for plastic applications, apply it where the pieces mate, mount it, install the one good bolt, and pray I never had to fool with it again.

I’d make sure that solenoid was functioning properly and that it wasn’t already sealing as it is before I did that, though.

why is buying a new canister not an option . . . ?

Surely you can buy an aftermarket canister on rockauto.com for a reasonable price . . .

That’s a very unusual arrangement. I don’t think I’ve ever seen a situation where there’s two captive nuts, one on the outside, and the other on the inside surface. You’d think that would prevent the bolt from threading properly, unless the two nut threads were somehow aligned. Perhaps only the inside nut is the captive, and the other one on the outside is some kind of space-filler to prevent leaks.

[George_San_Jose1]: You are correct. The round piece of metal that is on the stem/shaft of the broken bolt that you see on the photo is the round metal space filler. A photo is attached with explanation. I was able to use a dremmel tool and a screw driver to cut the plastic around it.

1 Like

$400.00 may be reasonable to some.

How do you know it’s $400 on rockauto . . . ?

He didn’t even mention the make, model and model year . . . not in the beginning of this discussion, in any case

With very little investigating he has a 1997 Nissan Sentra
https://www.rockauto.com/en/catalog/nissan,1997,sentra,1.6l+l4,1213175,exhaust+&+emission,vapor+canister,5180

Have you removed the vent valve from the canister yet? If you haven’t yet, look at the link @It_s_Me provided. Click on the little picture and then on the arrowhead in the upper right corner until you get the view of the side of the canister that the vent valve is mounted too.

The captive nuts, at least on this replacement piece are square nuts molded into the plastic. If you take the good bolt off and the captive nut on the bad side is loose, you should be able to pull the vent valve off. If you can’t, then the captive nut is still captive and you just need to put your vice grips on the remaining bolt and turn until it comes out.

If it does pull out, get a new square nut the same size from a hardware store and JB weld it back in place.

$400 for THAT? Hey, instead of typing on our keyboards here we should go into the business of making vent valves canisters… lol …

The canister is $403. You ought to see what one costs for a Subaru.

I appreciate all of your comments.
Keith: I already used a Dremmel tool and took the old solenoid off from the canister.
I am thinking about JB Welding a captive nut and using RTV around the mating surface. However, I want the best advise from the good people of this forum before making my decision.
It is a 1997 Nissan Sentra. Shelling out several hundred dollars for new a canister is not an option for me. Furthermore, the old canister’s fasteners are very weak. I don’t have a welding machine to weld back the fasteners if they snap.

I said I was done but there are just so many ways of dealing with this. Maybe you could find a square nut but I haven’t seen one for a long time. At any rate depending on what you find inside, you could just stick a bolt through from the inside. An internal lock washer and a glob of JB weld to hold it in place. Then you just use the original bolt on the one and a nut on the other.