Front pads rubbing on rotors

**parraeel** · 22-11-2008, 10:28 AM

I just installed new front brake discs, and have noticed that the pads are rubbing on them as I am driving. The pads were not changed as they are not that old. Is this normal until the discs bed in, or should it be checked out?

**h100vw** · 22-11-2008, 10:36 AM

It would be normal to change the pads and discs together.

In Australia there seems to be a habit of skimming discs which I am not a fan of. In the UK chucking new pads in without replacing or machining discs is the norm.

I think you'll find that the pads will bed in to the discs in time. If I were doing that job. I would have flatted the pads off with some sandpaper before fitting them

Gavin

**Ben_GTI** · 22-11-2008, 10:50 AM

From my conversations with various brake fitters and mechanics the pads should touch the discs very lightly. The reasons for this I've been given are;

1. Keep the pads / discs warm because brakes do need a little heat to keep dry and work effectively.

2. Stop dirt/dust/rocks getting between the pad and the disc. If dust and dirt were good for braking, they'd make the pads out of it.

Keep in mind the brakes on a car do a hell of a lot more work than brakes on a bicycle or go kart where often the pads won't touch the braking surface. In these applications it prob makes 2/5ths of bugger all difference, but in a car it would matter.

**Grant** · 22-11-2008, 02:02 PM

Can't you slightly retract the piston on the caliper when changing the rotor? As the new rotor will be slightly thicker than the old one.

**h100vw** · 22-11-2008, 03:00 PM

Originally Posted by Grant

Can't you slightly retract the piston on the caliper when changing the rotor? As the new rotor will be slightly thicker than the old one.

You would do that anyway. Thing is the first time you put your foot on the brakes it pumps the piston back out.

Once the pads surface wears to match that of the disc, all will be good.

Gavin

**Midnightmods** · 22-11-2008, 05:05 PM

Brake pads are always in contact with the rotor face.

If it wasn't you would get a delayed brake, bad pedal feel and poor braking,

**parraeel** · 22-11-2008, 09:40 PM

Originally Posted by h100vw

You would do that anyway. Thing is the first time you put your foot on the brakes it pumps the piston back out.

Once the pads surface wears to match that of the disc, all will be good.

Gavin

I thought I'd ask here, but that's what I was thinking, that after time the pads and discs would be bedded in. The discs have only been on the car for 4days, so it will probably be a bit longer until all is good
Thanks everyone for your answers

**Oneofthegreats** · 22-11-2008, 10:59 PM

Brake pad's are only in contact with the brake disc's surface when the brake pedal is applyed or when the handbrake is.

When these two thing's are not operated, the brake pad's are not in contact with the disc surfaces!

I bet half of you don't even know how the brake pads are retracted away from the disc surface when you take your foot off the brake!

**Blitzen** · 23-11-2008, 10:44 AM

Originally Posted by golfworx

I bet half of you don't even know how the brake pads are retracted away from the disc surface when you take your foot off the brake!

Oh, oh, I do , I do!!! (sticks hand in air with a sloppy grin on his face)...

The seal that seals between the piston and caliper distorts a small amount under braking and allows piston travel as well...When brake pressure is released(ie: When you take your foot off the brake), the distortion of the seal allows the piston to move back into the caliper, plus the rotation of the Brake Disk on the pads allows for a small amount of 'push' on the caliper too.