For those of you who haven't had the LCP apart, the reason that a previous post may have advised to raise the front of the FRAME INSERT (12), is that this method "may" prevent releasing the spring pressure on the HAMMER CATCH (27). If you can do it that way, well OK then, but be aware that you'll be dealing with the spring compression from the HAMMER SPRING (25) when you do it this way, and if you hear and feel something go “pop,” that’s probably the HAMMER CATCH (27) releasing and it will need to be “reset.”
Here's a more complete and detailed method. It’s not too complicated really, but if you’re not mechanically inclined it’s better to find a friend who is or send your LCP to Ruger and have them do it.
1. Unload and remove the SLIDE (1) assembly. Set the slide assembly aside. Degrease the frame to prepare to work. Don't fight the lube; wipe it off as you go.
2. Work in a well lit area where you will not lose small parts, especially springs which could go flying if you lose your grip on them. A small bench vise with protective jaws or inserts is VERY helpful while doing this and HIGHLY recommended as you’ll need 3 hands if you’re anything like me.
3. Remove the HAMMER SPRING SEAT (34) by inserting a punch or jewelers screwdriver into the catch hole on the lower rear of the frame. Don't force it. Once you release the catch, it'll come out with simple hand force.
4. Make a loop of a small strong wire (a straightened paper clip works very well) about 1.5” in diameter and twist the ends. Catch the bottom hook of the HAMMER SPRING (25) with this wire and insert a punch or screwdriver shaft through your wire loop. Unseat the HAMMER SPRING (25) by pulling up and remove it from the HAMMER SPRING SEAT PIN (33). Allow the spring it to retract into the frame. Remove the HAMMER SPRING PIN (33).
5. Using a 1/8” punch, drift both FRAME INSERT PINS (29) out. They will drift in either direction.
6. Lift out the FRAME INSERT (12) assembly. You will hear and feel the “pop” of the HAMMER CATCH (27) releasing when it unseats from the HAMMER (23) as you lift.
WARNING: DO NOT PULL THE TRIGGER while it is out of the frame as this will unseat the TRIGGER BAR (1 and HAMMER CATCH SPRING (26).
CAUTION: The HAMMER SPRING RETAINER PIN (22), which holds the HAMMER (23) in the frame may have a loose fit and fall out.
7. Hold your finger over the body of the HOLD OPEN DETENT (21) spring to retain it in its housing and unseat the spring from the HOLD OPEN (19) using a pair of sharp nose tweezers or tiny jewelers screwdriver. Remove the HOLD OPEN DETENT (21) spring from its housing being careful so it won’t go flying and be lost.
8. Slide the HOLD OPEN (19) out of its channel toward the top of the FRAME INSERT (12) and insert the new one. Be patient and don’t force it.
9. Insert the body of the HOLD OPEN DETENT (21) spring into its housing and using a pair of sharp nose tweezers or tiny jewelers screwdriver insert the spring arm into the HOLD OPEN(19) groove. Check the operation of the HOLD OPEN (21).
10. Using a small diameter punch or flat bladed jewelers screwdriver, move the HAMMER CATCH (27) forward and hold it there against spring pressure. Place the FRAME INSERT (12) assembly into the frame, trigger end first, and lower into place until the HAMMER (23) engages with the HAMMER CATCH (27). Remove the punch or screwdriver and fully seat the FRAME INSERT (12) assembly into the frame.
CAUTION: Hold the FRAME INSERT (12) assembly in place until you get the FRAME INSERT PINS (29) started as the spring pressure on the HAMMER CATCH (27) may cause it to unseat.
11. Install the two FRAME INSERT PINS (29) into the frame and lightly tap back into their holes.
12. Install the HAMMER SPRING SEAT PIN (33) into its housing grooves on the frame. Catch the bottom hook of the HAMMER SPRING (25) with your wire loop that you made for this. Insert a punch or screwdriver shaft into this loop and pull the HAMMER SPRING (25) up and onto the HAMMER SPRING SEAT PIN (33).
NOTE: There are two detent grooves on the HAMMER SPRING SEAT PIN (33) - use the rearward groove which will properly align the HAMMER SPRING (25) in its channel in the grip of the frame so as not to interfere with the magazine.
13. Reinstall the HAMMER SPRING SEAT (34) and reinstall the SLIDE (1) assembly.
14. Perform a complete operational check of the weapon. Recommend that you also test fire the weapon prior to carrying it as your carry gun, just to be sure.