The lead to a zipper on chaps has separated from the rest and the

if your are meaning the pull tab on the zipper for chaps has come off,,in a pinch you can use a paper clip as a pull. if the zipper has separated the full length of the leg- line up the zipper teeth and see how it goes. the zip might need replacing.

you might have to take them to someone who can handle the heavy fabric, if the zipper is broken, maybe ask a dry cleaner?

Agree with Elizabeth.

The zipper might have to be replaced. An industrial sewing machine will have to be used to replace/repair it. Your local cleaners might not have such. Best to take it to an establishment that deals specifically with leather cleaning and repair, an alternative possibility might be a shoe and/or purse repair shop.

Take them to a cobbler. They work with leather and would be able to tell you what needs to be done to repair it.

hum... I'm not familiar with those products nor am I certain of the 1/4" fabric you are referring to (I'm guessing the fabric the teeth of the zipper is connected to), but on any account, perhaps a mixture of the fibers and a dap of resin might work. It might help solve your challenge if you could post a photo, good luck nontheless.

Paule, have you had any luck yet with the zipper on your chaps?

I think I understand what the problem is. Could you post a picture of the damaged area? That way we could see exactly what you have to work with.