The hole where the circlip goes in when on the shaft is tapered. That forces the clip to shrink in diameter as it goes in. Once in all the way, the hole will have its own groove where that ring can expand to hold the shaft in place.
There are two problems I've run into with this design. The first is the new ring is made from larger-diameter wire than the original one was. It is possible to get them to work, but it is much easier to reuse the old ring, when you still have it. (Also consider your old ring might have been one of those larger replacements already, and it broke when the last person forced it to go in). The second problem is the ring has to be expanded to slide in onto the shaft, and that can stretch it so it is larger than the tapered area of the shaft it is going into. If it does not start going into the tapered area, it cannot be compressed to go the rest of the way in. To solve that, I use a pair of pliers to bend the ring to a much smaller diameter, but be careful that it remains round. Now when it gets stretched to be placed on the shaft, it will have enough "memory" to shrink down tighter on the shaft. When you go to slide the shaft in, wiggle it up and down and sideways as you push it in. That will help to start the ring going into the tapered part of the hole. If any part of it hangs up outside the tapered area, the shaft will not go in, and pounding on it will just deform the ring and destroy it.
As a last resort, find an old shaft at a salvage yard, hope the ring is original, and use that one. It is likely you will find it is made of smaller diameter wire than the one you have been trying to use. I have never done this, but I suspect auto parts stores will have replacement rings too, and they may have an assortment that includes one closer to your original ring.
Friday, June 23rd, 2017 AT 2:40 PM