Need parts,Where can I buy a ear hook and rubber

No, finding spares for Headphones is difficult since they are all different, it's not the same as cabinets or speakers. You are better off buying a new pair and keeping your old ones as a spare.

you need a part number or need to know where to buy the part

Hi,to complete the look of a tech-savvy, iPhone-using individual, you must have a Bluetooth headset to accompany it. You can pair any Bluetooth headset with an iPhone. The Motorola HS850 is no exception to this. Both Motorola and Apple's Bluetooth set-up process is fast, so you'll be talking with people through your new Bluetooth on your iPhone in a matter of minutes.

Instructions

Charge the Motorola HS850 headset fully before attempting to pair. Usually, it takes two to three hours to charge the headset.

Press and hold the "Call" button (has a phone icon on it) on the headset for six to 10 seconds. The outside LED light will turn on indicating that the phone is in pairing mode.

Choose "Settings" on the iPhone homescreen.

Select "General," then "Bluetooth."

Select to turn Bluetooth on.

Wait for the phone to search for in-range devices.

Select theMotorola HS850 from the list of devices.

Enter the headset passkey to complete the pairing. By default this is "0000."

Have a nice day..

Hi this is quite a common problem, you have a couple of options you can either go out and buy a new door rubber seal or if it one of those seals where you can get you hand in between two parts of the seal then what you can do is get some thick string and run this in the middle of the seal doing this will pack the seal out a bit and then when the door is shut this will make a lot better seal and it will then stop the water getting in.

let me know if you need further assistance ok

ps the rubber seal isnt to expensive to buy but even a new rubber may still have the same problem as its more to do with the way the door is fitted and it seems it dont push the seal hard enough to prevent water getting in so i have found packing it out with some thick string or twine will push the seal out more and will seal it properly when you shut the door to

plz rate this solution as i have a whole page of unrated posts, thanks

Your headset may also be called a HS850 (may look different) but the instructions would be the same. Instruction manual is here:
http://www.motorola.com/mdirect/manuals/HS850_%209489A97O.pdf

any radio shack, or a local cell phone dealer

You can find the replacement ear hook for this bluetooth on EBAY.COM. The one I found was going for $.39, Buy it now price $1.00.

I bought a new HS850 and guess what, I got this hearing problem on the very first day ...phew ! I did the pairing with my Motorola A1200 phone and it worked for once, even the sound was coming in the earpiece and then I put it to charge for the first time and once done, I again started it up and it got connected with the phone and after that there was no sound in the ear piece. I was going nuts....about what could be the problem.

So i decided to delete the earlier paired profile from my phone and do the pairing again and guess what...It Worked....:) So you can try that out too....

You can't buy a replacement ear piece but you can buy a new H500 for $19.99 US. Not including shipping.
http://www.tigerdirect.com/applications/SearchTools/search.asp?keywords=h500+bluetooth&image12.x=17&image12.y=18
I use the H700 and a few others. Seems most die before they break so why pay more for less.