Will I be able to access my Time Machine backups after changing Hard Drive
Yes, you can access the backups after changing the drives out. If you control-click or right-click on the Time Machine app icon, one of the items is "Browse other TIme Machine Disks..." from where you can select your Time Capsule backups. You can also re-associate your new drive to the old backups in Terminal with tmutil so that your backups will continue as if the drive change never happened. There's a good set of instructions here on how to use tmutil to accomplish that.

One of the other options you have is to do your clean install and then use Migration Assistant with your Time Machine backups to restore all your files and settings.