My Pfaff 4.0 breaks needles and shreds thread when free motion quilting

A sewing machine I work on last week, I put a new needle in the needle clamp & thought I had it correctly inserted,, but it wouldn't work,, so I went back & checked the needle again & found I had to unscrew the needle clamp screw even more than normal to insert the needle then it work perfectly.

some needles & thread don't work togeather--here's a tip
Cut 6-8 inch piece of thread of the spool you are going to use for your project
Take the needle you are going to use for the project
& insert the thread thru the eye of the needle
& lift one end of the thread to a 45 degree angle
& if the needle is the right size for the thread it will slide down the thread
But if the needle hangs on the thread you need one size larger needle for the thread

also clean under the needle plate where the feed dogs are for lint
& also in the bobbin area for lint & loose threads