i have been trying to change the front discs but i just can't seem to get them off!

is this a common problem and can anyone offer any advice on how to get them off.

many thanks

 

it all depends how long they have been on there, but they can seize on the hub you'll have to hit it with a mallit working around the disc and it will eventually come off,
You have removed the retaining screw i assume.

 

As said after screw is out, hit the CENTRE of the disc, as I have found this to be a LOT more effective than clouting around the outside, they don't get very tight on sierra's compared with say a mondeo.
On some cars I have even had to saw through the disc splitting it in two, as this releives a lot of tension making it a lot easier, good luck.
I always use copper grease between hub disc to prevent a repeat performance, after thoroughly cleaning the hub face.
tabetha

 

i will be honest i don't know nothing about a retaining screw can someone tell me where it is!

any pictures!

it doesn't say anything about a retaining screw in the manual.

just to confirm, it is a 1987 sierra rs cosworth 3 door.

many thanks

 

The screw is on the flat section of the disc onto which the wheel centre sits, it will be halfway between two of the studs sticking out if fitted.
tabetha