This subject has been discussed many times and I was in the process of rebuilding the valve on the '63 4000D so I decided to photograph it.
1) Use a hammer to drive the blade of an old pocketknife under the head of the rivet. Wiggle the blade and the rivet will start coming out. Use a screwdriver to pry it on out.
2) The lower stem is the only one I've ever seen until I worked on this valve which has the upper stem. Regardless of which style you have you need to replace the o-ring.
3) Drill the rivet hole with a #29 bit and then tap it with 8-32 tap.
4) The tip of the screw drops into the groove to keep the stem from backing all the way out. If the screw is too long it will dig into the stem as you tighten it down. I grind the threads on the tip of the screw so as to form a small blunt pointed tip.
5) Lube the new 0-ring with plenty of Vaseline, reassemble the stem into the body and tighten down the screw. The next time the valve starts leaking you can use a 90* bent Phillips screwdriver to remove the screw and replace the o-ring with the valve still installed on the tank.
1) Use a hammer to drive the blade of an old pocketknife under the head of the rivet. Wiggle the blade and the rivet will start coming out. Use a screwdriver to pry it on out.
2) The lower stem is the only one I've ever seen until I worked on this valve which has the upper stem. Regardless of which style you have you need to replace the o-ring.
3) Drill the rivet hole with a #29 bit and then tap it with 8-32 tap.
4) The tip of the screw drops into the groove to keep the stem from backing all the way out. If the screw is too long it will dig into the stem as you tighten it down. I grind the threads on the tip of the screw so as to form a small blunt pointed tip.
5) Lube the new 0-ring with plenty of Vaseline, reassemble the stem into the body and tighten down the screw. The next time the valve starts leaking you can use a 90* bent Phillips screwdriver to remove the screw and replace the o-ring with the valve still installed on the tank.
