hotpoint dryer problems

hpt CTD85A
with loads of problems.

1)
there are 3 button stats above the heater assembly on this model.
2 black stats , one with a white spot on it, these look like a regular set of 1703200 sats.
the centre stat is a white one, is this supposed to be normally open or normally closed?

2)
the plastic strip seperating the metal band that goes round the drum that the brass brush sits on has come out .can this be replaced?or do you have to replace the drum?

3)
the machine is making the most terrible noise. thought it was the fan at first but that seems fine, it seems to be the plastic wheels the drum runs on, is there a convertion kit to do away with them for this model?

thanks.
john