For the headset, it's the top cover, normall on low end headsets its cheaper to replace the whole unit than find spares. you can see a parts breakdoen here, look at the 100 classic threadless instructions http://www.canecreek.com/tech-headsets?view=manual You could always ask at a bike shop to see if they have this part in a spares bin.
For the brakes, it's just a dust cover, in your case, would cut it off, as replacing would require the hoses to be removed from the caliper / lever and when re-installed would most likely require a bleed.
Hey man, thanks for the quick reply. What info do I need to find something that fits? Are there different sizes? Thanks.
Originally Posted by jimc101
With headsets, there are so many different designs and sizes around, that unless you have a high end one, like a Chris King, where parts can be obtained, it is normally easier & cheaper to replace the whole unit. I mentioned asking in a bike shop, as you may find they have the part yours has broke in their spares bins, if they keep salvagable parts from previous work they have done.
Unless you have the correct tools, headset replacement is a job normally better left to a bike shop.