Does anyone have experience swapping hard drives in the Pioneer recorders?

My DVR-640H decided to say "no space left on the hard disk" even though I've tried deleting (small) things, letting it do the hard disk repair, and I've also tried optimizing the hard disk (not enough space to...).

So, here are my questions:

1. It appears that if I put in a blank 160GB hard disk, I will probably get the option "Format Hard Disk" instead of optimize hard disk in the disk setup menu, so I'll be able to run with a new hard disk, but...

2. Will it still let me put the old hard disk back in and read from it, or will it try to reject my old hard disk (and if so is there a work-around to this)?

Or does anyone know a way to force a "better hard disk repair algorithm" which might fix the free space?

thank you,
--Gary
P.s. any tips on the mechanics of changing the hard disk in this model?

At PioneerFAQ (http://www.pioneerfaq.info/english/dvr630.php?player=DVR-630H&question=replace_hdd) you will find information on how tp swap the hard disk in your DVR-640H, scroll down to: 2006 models and above and download the PDF file: DVR-440/540/541/543/545/640/645H(X)

Thanks ! But once I prepare a new hard drive, will it still let me swap the original drive back in?
--Gary

I'm not really sure what you mean, but, yes you can put the old HDD back in and it will read whats on it.

I want to confirm something here, so basically I can install a larger drive in the 640 recorder in place of the 160GB drive that is in there now and the recorder will function as normal with the new larger drive w/o any problems at all? thanks