look, not trying to discourage you or anything but those wheels have a tendency to lock themselves to work, pull that out and you will find it veeery hard to re mount them properly, if you do id mark the teeth where they align now or you'll be in a lot of pain sanding down teeth to get it working again and good luck not wrecking them. and from previous posts you don't seem to have many parts for that model unlike the k7 models
Did you try first changing the needle like someone said before? did you try pulling out foot presser clean it proper? how did you remove all the old oil? how long was the machine sitting idle before you picked it up? you say you cant produce stitch, you dont pick up bottom thread? are you breaking needles is the material not dragging at all? it looks like a timing issue like a user said true,can you not regulate the timing on a k3? He pointed out how your pressure foot is grinding on something and not going down right. it could be bent to hell by now, and not a wrong assembly. id focus on getting that motion (pressure foot going down to needle plate) smooth and making sure its the RIGHT NEEDLE before starting to open it up.
took me 4 days to get the foot pressure just right on that machine, and its pretty much set up to press the material so hard imma scratch the leather to hell and it still has crappy feed. perhaps there is a reason machines these days got triple feed?
if you do want tips on getting those pins out well, get something with the same size width of said pin, and make sure you wack it the right way!!! he comes out 1 way NOT the other.