QUESTION: How does a pendulum hook to the suspension leader?
ANSWER: The answer is in your question. They just hook on. Without seeing your leader and pendulum I can't help. If it doesn't just hook on then you might be missing something, but again would need to see a picture.
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QUESTION: Here is a picture ,i can take more if needed
The pendulum hooks into the square hole on the leader. You did not show the top of the pendulum, so there might be something missing there. But from the picture of the movement everything is there . I just looked at the picture again and it looks like your suspension spring is broken. It hooks you leader to the suspension post. If you have a local clock repair shop they should have a new suspension spring. Otherwise you can order one from Merritts antiques out of douglassville, Pa. It's where I buy all my parts from. You can buy from them also. Shipping will cost you more than the part, thats why if you have a local shop it might be cheaper. Below is a link to merritts suspension spring. You need P21.2, or one like it.