Brake Pad Change - Grinding?

[Cunning Plan]

Hi guys, Just swapped the pads over on the Ford and it was pretty much like every other pad change Ive done, no real tricky bits at all..

Heres the problem, normally a few compressions of the brake peddle will 'self-adjust' the new pad against the disk once you have pushed the piston back to get the new pads in..  

This never happened with the Ford, but I figured it would sort it self out when I took it for a run but it hasnt.  It makes a grinding noise with the brake off, if you touch the brakes slightly the noise stops.  The brakes arent that great at all but thats normally always the case when you swap the pads as the new pads need time to bed in..  Its almost like the pads are vibrating around in the caliper because the piston isnt holding them against the disk..  Is there something on newer fords I dont know about?

Any ideas?

[art b]

is the disc worn, is there a ridge on the edge..?

[55starchief]

Isnt there a screw you have to wind back to bring the piston to its original placment. If you have compressed the piston back you mighr have bent the return screw

[Cunning Plan]

Quoting: art b

is the disc worn, is there a ridge on the edge..?

Yes it is the old disk which has a slight lip of rust.  

Spoke to a mate of a mate of a mate who is a mechanic last night..  He said that a new pad will be bigger than the old one and will not of 'shapped' itself to the disk so will be grinding on the rust lip.  He explained that normally they clean up the edge of the disk to stop this happening at a garage if they arent replacing the disk.  

This makes sence, he just said take it easy.  Most other pads ive change have been 'soft' for a bit but soon bedded in with the brake peddle nice and firm.  For some reason the ford is taking a while, the peddle is still quite spungy, but on the way to work this morning it was better than yesterday...  

Quoting: 55starchief

Isnt there a screw you have to wind back to bring the piston to its original placment. If you have compressed the piston back you mighr have bent the return screw

I had a quick look on the caliper to see if theres anything extra on it but couldnt see one..

So there ya go, if replacing your pads and you are leaving the disk, clean up the rusty edge first or its very noisey for the first couple of hundered miles!!  

[55starchief]

Quoting: Cunning Plan

So there ya go, if replacing your pads and you are leaving the disk, clean up the rusty edge first or its very noisey for the first couple of hundered miles!!

Yup i always file the edge of the new pad

[Rocky]

We always clean the disc anyway. As Greame says some calipers do screw back something you have to watch for,

If it does  continue it could be a sticking caliper.

[Cunning Plan]

Quoting: Rocky

We always clean the disc anyway. As Greame says some calipers do screw back something you have to watch for,

If it does continue it could be a sticking caliper.

[art b]

the old disc edge is a favorite,
i take the ragged edges of the discs with a flap wheel thingy, on a grinder....

[Cunning Plan]

Ok, ride home its still grinding, figure ive just got to wait for it to grind down..

Heres a question I thought about on the way home..  How come that new cars with 0 miles on dont need to be treated any differently from cars with their pads worn in?  New cars have new disks, pads and fluid right?  How come they just 'work'?

[55starchief]

Quoting: Cunning Plan

How come they just 'work'?

They dont, we had a rover vitesse on loan from a dealership a few years back with delivery mileage, after all of us ragging the titsy off of it pulling up to stop at a roundabout a bit quick we see a cloud of smoke from the discs

[Roadkill]

Quoting: 55starchief

They dont

You'll get a list of "do's and don'ts" with a new car . . .