How the hell do i get these things off to put on new ones? admittedly they are quite rusty from the previous owner. Ive done the front ones with relative ease but the back ones are just confusing me. Any help with getting the rotor off will be excellent. Also in the back left wheel i get a clunky noise when driving. ive been told this is an arm?? whatever that is too ill get it done at the same time.
Cheers!

 

Assuming you have released the handbrake, to remove the rear rotors you will need to back off the parking brake shoes first either by tapping the rotor with a mallet or if this fails, putting a tool through the hole to manually wind back the adjuster.

The clunking noise you hear in the rear is most likely the top of the shock sleeve wearing through the top spring mount. This happens as a result of badly worn upper shock mount bushes. If it's not too bad then you can obtain a new spacer sleeve and bushes and get the spring pan welded as a fix. If it's bad then you may need to also replace the shock(s) and upper spring pan. The whole rear spring/shock assembly can be removed from the car in one unit so you can work on it on a bench.

To tackle these it is best to get yourself a haynes manual to guide you through the procedure. It's not complicated, just dangerous if you get it wrong and a spring smacks you in the face.

 

as pointed out, normally, they are pretty simple to remove. you do off course need to remove the caliper and pads. on the disc, there is sometimes, unless its been removed previously, a retaining screw that was fitted at manufacture, to hold the disc in place for the fitters. these can be a bit rusted and tight, but nothing an impact driver won`t move.
again, as mentioned, make sure the hand/park brake is `off`. if the disc/rotor wont just pull off, with a hammer, just give it a few hits all round the rotor and this should slacken the brake shoes off. then the rotor should just slide off!
couple of important things to remember as well. always replace pads when changing rotors/discs and always avoid heavy braking for around 100 miles, to allow the pads and rotors/discs, to `bed` in.