It's an old boat. It probably needs some work. You bought it, take ownership of the problem and fix it until you trust it. Either that, or sell it and buy a new or refurbished boat that is "sail ready", that you feel you can trust out of the box.
I get the impression that you're not mechanically inclined. Now is a great time to learn. Bristols are good boats, give her a little love and you'll be able to trust her.
S/V Old Shoes
1973 Pearson 30 #255