K98 makes that rifle 60+ years old and through multiple owners. How many of them maintained it properly? Btw, the firing pin spring is properly called a striker pin for the Mauser.
http://www.gunsprings.com/Rifles%20%...2/mID40/dID424
When I first acquired my Mauser, I bought the Wolff Service Pack and then learned how to strip and clean the bolt.