CVA Lock Sear Replacement Instructions

[Muskeg Stomper]

I picked up a used CVA Squirrel Rifle for my daughter to shoot. The sear is chipped and the set trigger adjustment screws were real loose so I ordered replacement parts from Deer Creek. What I'm hoping is that some of you folks on the forum can provide me with step by step instructions for disassembling a CVA lock and replacing the sear. It sure ain't a Siler lock and has a wire sear spring. I'm at a loss. :idunno:

Pictures are worth a thousand words.

Thanks in advance.

 

[Muskeg Stomper]

Correction, this lock has some kind of funky looking sear spring but not a type that I'm familiar with.

 

[paulvallandigham]

1. Remove the mainspring. This takes the tension off the tumbler.

2. Remove the sear spring. Its held on with one screw, and then some kind of notch or hole in the lock plate.

3. Replace the sear spring with the new sear spring.

4. Replace the mainspring.

You are done.

Check Bob Spenser's Black Powder Notebook for Percussion lock terminology and pictures of the backside of most percussion locks. Some have coil springs instead of flat, or "V" springs.

Coil spring will usually have a strut running up the middle of them, and, when the hammer is cocked, a hole in the strut large enough to put a small nail, or paper clip is exposed. You put the wire or clip through the hole, and lower the hammer.

This compresses and holds the coil spring to the strut so that the entire unit( spring and strut) are lifted out of the lock. You want to use the lock's own leverage to compress any spring, before removing it, as that takes that spring's tension off the parts it affects. Depending on how its constructed, you may receive simply a new coil spring, which will require you to remove the existing spring from the strut. Clamp the strut in a bench vise, or even vise grips, and pull the pin from the hole. Then slowly release the strut from the vise, holding onto the spring and strut. ( Put a rag over the palm of your hand so you don't stab yourself.)

To compress the new spring on to the strut, hold the strut in your vise, leaving room for access to that hole. Now use needle-nose pliers, or some other form of tool( you can drill a hole in a piece of steel or aluminum, or thick brass, and run that down on the strut, to use to compress the spring. When its compressed, slip your wire into the hole to hold it. Now you can replace the strut and coil spring in the lock.

I don't know what your particular CVA lock spring look like. There were several different designs used by the company. I have two of them. One uses a coil spring for the mainspring, but the other doesn't. I didn't find a coil spring being use as a sear spring in either gun I have. But, that doesn't mean its an impossible problem to solve.

Locks are fairly straight forward machines. The pictures in Spenser's site should give you an idea of the relationships of the various parts to each other.Working the lock while watching the backside of the lock to see what moves, where, and when will quickly teach you how the lock is designed to work. :hmm: :thumbsup:

 

[Muskeg Stomper]

I need to replace the sear, not the sear spring. It's just that I'm not familiar with a sear spring setup such as this one. See each of the four linked photos.
1 2 3 4

 

[Rogue River]

In picture # 2 it shows 3 screws. Remove the LOWER of the 3 screws and the sear will slide out. Replace sear and tighten screw. You will have slight pressure from the sear spring so you will have to squeeze the sear up to line up the screw hole.

 

[Muskeg Stomper]

Thanks Paul & Ron. Between the information that both of you provided, I think that it'll work. It appeared to me that if I removed all three bridle screws, I'd have a heckava mess on my hands.

 

[paulvallandigham]

YOu will not have a " Mess on your hands", if you first remove the mainspring. For simply replacing the sear, just remove the bottom screw of the three. You will feel the resistance cause by the sear spring on the sear as you try to remove the screw from the lockplate. Push forward on the sear BAR, and upward at a 180 degree angle to that sear spring, and removing the screw without damaging either the threads in the lockplate, or on the screw will be straight forward. The tension on the frizzen spring should not be very hard- as its only job is to return the sear to its position IN the notch- either half cock or full cock, when the hammer is cock.

I like to remove the mainspring, and then remove the entire bridle, by removing all three screws, so that I can "dry fit" the nose of the sear to the notches in the tumbler.

To do this, put the screw that holds the sear thru the sear, and into the lockplate. The sear spring should be remove or deactivated, and there should be no mainspring in place. Now move the tumbler while putting pressure down on the sear bar. Check to see that the nose of the sear enters the notches in the tumbler properly, and completely. Check to make sure that the nose doesn't stick into the half cock notch when the hammer is rotated forward from the full cock notch.

Sometimes, I find that new parts need casting burrs removed, with a fine file, to fit properly and work properly. The side of the new sear that rubs against the lock plate should be as smooth as a baby's bottom, and free of burrs. You don't want added friction on the sear. I have even filed a bit of clearance ( .001-.003"), on some sears, to make sure that the only friction is right where the pivot point of the sear is held to the lockplate by that bottom screw. If the nose of the new sear has not been ground to shape, use the existing sear, damaged and all, as a model to guide you in shaping the nose. And, you never know if a replacement sear has been hardened or not. Test it in a non-critical area with a file, If you can cut steel with a file, it probably needs to be hardened and tempered after the fitting is done. :thumbsup: :thumbsup: