Volvo Repair: Volvo 760 grinding noise on driver side when braking, volvo 760 gle, car novice

Question
Hi,

I own a Volvo 760 GLE (89) - Left Hand Drive.  

For a while now I have been experiencing a grinding noise on the left hand front while braking at low speed. The other day my spring above the right hand side wheel went and I attributed the grinding noise to that. But since I got this fixed today, the opposite side noise still persists.

I've tried to look at the silver disc behind the wheel and i can see a 1.5 to 2 cm thick ring around the edge as if it has been worn away.

My question is (and I'm a complete car novice) - what causes this and what needs to be done to repair it. Can I expect I hefty bill or is it relatively easy to fix myself?

Thanks,
Adam  

Answer
sounds like thge pads are worn down to the metal and needs to be replaced.if the rotor thickness is ok this is the silver disc then you mAY BE ABLE TO REPLACE JUST PADS.IT SHOULD BE LOOKED AT TO HAVE THE ROTOR THICNESS MEASURED TO SEE IF THE ROTORS ARE OK.