If a vehicle has disc brakes fitted on all four wheels....

[Craftypig]

when you press the brake does it operate all four brakes or just the front two?

[chas2008]

it operates all 4 with different degrees of pressure (front to back) depending on circumstances & type of vehicle.
I take it you think the foot brake works the front and the handbrake works the rear ?

[Craftypig]

No, but when I press the brake there is a griding noise, I have checked the brakes all round and the rear near side pads look like it could be the problem, the disc is badly scored there is a great deal of rust residue on the tyre. So im thinking it's either ceased onto the disc and the grinding noise could be coming from one of the other brakes or that particular pad is the problem. wanted some up front advice before I go to the garage. to be forewarned is to be forearmed etc etc...

[ChuckFickens]

The scoring in the disc is a bit of a give away, the pads sound like they've worn out totally and you have the metal back plate scraping on the disc.

You'll need a new set of pads and discs by the sounds of it.

[deggers316]

sound like an accident waiting to happen,expect a large bill

[RATTER15]

As Chuck said^^^

[chas2008]

just out of interest which vehicle is this ?

[gingejbee]

If the car is used mostly lightly-laden and the driver drives it "gently", the rear brake discs can become corroded through under-use because most of the braking effort goes to the front brakes. Some cars are much worse than others in this respect.