685B Monopod need a replacement rubber foot for 685B monopod

Sorry this site doesn't have any parts or anyway to look them up for you.

You could try your local friendly camera store, or look on Ebay for a similar item. Alternatively, try contacting the manufacturer. If all else fails, cut a correctly sized piece from a classroom eraser and attach it with gaffer tape.

You should not need to change the thread size on your monopod. All tripods, monopods, cameras and other accessories have standard fittings. Check that you haven't accidentally crossed the threads on your Panasonic which would make it difficult to locate the threads to tighten it.

Also, check that you are not trying to screw the monopod into the hole. Some cameras have a smaller hole beside the tripod thread.

You may be able to contact your monopod manufacturer in case they supply an adapter that wasn't supplied with your monopod.

You can find parts at www.ManfrottoTripodParts.com
Depending on how much work it needs you will need leg locks and a foot and possibly a head.

I had the same problem with the Manfrotto 685B, and it was due to the grease from the middle section leaking into its locking mechanism. I fixed the problem by: 1. Detach the middle from the bottom section by twisting the metal hub between them counterclockwise. 2. Wipe the grease off from the middle section's locking mechanism, especially from the three gray protrusions. 3. Use a bit of dish detergent to degrease the inside shaft of the bottom section. 4. Dry thoroughly. 5. Reassemble the section back, pressing the monopod release lever to facilitate the insertion. Reclose the metal hub. Ha! Fixed!!1!1!!eleven1!!

If it was second-hand or pre-owned, the previous owner may have applied some form of lubricant to it. From a look at the images on the Net, it appears that the upper sections are adjusted by twist grips. If this is so, just unscrew them and separate the leg sections carefully, after which they can be cleaned. There may be a bevelled collar within, to grip the section - be careful with it.
The bottom section seems to have a standard lever lock. There should be a couple of screws holding this to the middle section - loosen these, then slide the leg portion out and clean it as well. When re-assembling this part DO NOT over tighten the screws - just enough to prevent the locking collar from moving.

Tighten the lower half of the leg locks with, I believe, an 8mm socket. Only turn 1/4 turn and try, if not, try another 1/4 turn. Continue until leg stays in place/

You can order parts from:
www.bogentripodparts.com

Practice with the monopod before you start. If you haven't bought the monopod, get one with a snap lever like the Manfrotto 685B it has one button release, and a foot step so you can stand on the base and raise it quickly. But there is no trick to using, just lots of practice.

Contact Sunpak direct, they are required to sell parts.