Well the springs your talking about if you got it from Case IH it should be right though both of mine are like your old one, about 18" long. The fraying could be a bad knife, knives are easy to sharpen or cheap if you wish to replace, one screw is all that holds the knife on. First though to get to the knife you need to take off the drive bar that makes the knives cut, this is on the back of the knotters(chute side/rear side of baler) this has two bolts and a spring. Then on the front side of the knotter toward the arm that pulls hay into the plunger remove the bolt that holds the knotter forward, just follow the knotter to the frame. All these bolts use a 5/8" wrench unless they've been replaces with something non original. Once removed pull the knotter back and it will turn up, it will get to a point and not move, pull out on the bill hook tensioner and you will be able to turn the knotter up higher. Now that you can see the bottom you will see the knife and the 1 screw that holds it on, you can sharpen or replace the knife whichever suits you best. As far as the fraying and stuff it depends on what type of fraying and stuff is going on. There are only two things adjustable the bill hook tension and the knotter tension, you will see the bolts with springs on them when you turn the knotter(s) up. If there is fraying going on I would guess one has too much tension, is rusted or too much dirt and debris packed in it making it act as it is adjusted too much. If you go on ebay you can buy a operator's manual that will give you pictures of twine, you find the one that looks most like yours and it will tell you how to adjust. The manuals usually go for around $20 last time I checked. After you adjust it a couple of times and get it tuned right you'll be like man that's so easy, just remember you want just enough tension to make it work, most knotter problems are over tensioning. If you need more help give me a call (517)643-4479 my names Rob. If I don't answer leave a message I farm and don't have any cabs on my tractors and work construction so I don't always hear my phone but I'll get back to you.