mail man came yesterday and delivered a top lever tension spring and screw. I spent all night playing around trying to get it to work.
No, silly goose, the spring does not go down the hole with the screw behind it! Here is the correct sequence for installing the top lever on a lewis.
1. place spring horizontally across the groove in the cam. Insert the came and spring into the hole in the frame from the top. I found it easiest to have the groove facing toward the rear, and the rear of the frame pointing up. Use a pair of tweezers to lightly compress the ends if you need to. Also, one end of the spring was wound to a point. make sure the point is on the right side. The set screw won't grab the pointy end of the spring, and will slip off, jamming the top lever.
2) using a pair of pliers, rotate the cam clockwise until you see the top of the spring through the hole. Insert the set screw, and screw down until it stops, and then back off half a turn. Verify spring tension by either carefully rotating the cam with pliers from the top (don't bugger it up!) or using a flat screwdriver against the nub on the bottom. It should spring back If not, try again.
3) gently push the cam slightly below flush so you can slide the top lever into position. If it doesn't go, back the set screw out 1/4 turn so the cam will move a bit further down. Don't back out too much or you will lose the spring and have to start all over!
4) use a flat screwdriver against the nub on the bottom of the cam to align the cam head to the top lever. press the cam up into the toplever as you rotate.
5) insert the top lever screw, finger tight, and verify by pushing the top lever over to the middle that it springs back to the open position. The top lever screw and set screw get adjusted to tandem. In addition to holding the spring, the cone-shaped end of the set screw also controls the final depth of the cam in its hole. Backing off the set screw allows the cam to ride higher, which allows you to tighten the top lever screw a bit further. If you back off the set screw too much, it will lose the spring and you have to start all over.
6) with the top lever screw aligned, you can play with the set screw half a turn or so in either direction to adjust the top lever's closed position. Loosen the setscrew to send it further left. again, too much and you will slip the cam spring, jamb everything, and have to start all over.
Very frustrating...my original set screw that came in the shotgun wasn't pointy at all. of course it failed. The replacement wasn't only slightly pointy, and kept failing. Then I discovered the threads of the set screw are the same as those on the set screw in the bolt guide block, and the same as the ejector's retaining screw. The former was dome-shaped, and the latter was very pointy. I swapped and ....perfection. Except there is a little play/backlash in the top lever. This is due to wear. I made a 0.001" shim from some stainless shim stock to go between the top lever and cam. No play anymore, screw aligns with the handle, all is right in the world.
Mailman today brought a new firing pin...here was what was in the gun originally.
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half the head was sheered off!
The firing pins for the Crass (or at least one of the Crass variants) are the same as the lewis. The firing pin return spring was slightly different. Same with the top lever spring and set screws. My pin and spring came from eBay Crass listings, and with ancillary parts I don't need. I have a Crass top lever (the kind with cam fixed to the lever and no screw), two left V-main springs, a Crass firing pin spring, and a sear spring which is the same on the Lewis. If anyone needs these, this forum has dibs before I list them for sale.