S60 Brakes: Scraping noise when spinning rear disc/wheel

[ilmiont]

This seems like something basic which I can't reason through to my satisfaction.

I fitted new rear discs to lightly greased hub spigots, ensured they're flush, and installed the locating screw. When rotating the discs (or when rotating the finished assembly, wheels on, handbrake released, as shown below) there is a scraping sound for part of the motion, some of it is free though.

This shows up in a few of the how-to videos but with no explanation. Nobody addresses it or tries to resolve it so I have to assume it's acceptable but I want to know if it's something that could/should be alleviated. And I didn't think to spin the wheels before starting so I've not got a comparison.

+ YouTube Video

Is it the handbrake shoes dragging? I thought it was this, but backing off the nut didn't seem to change it; plus as you see in the video, with the handbrake released the wheel seems to keep rotating reasonably well once started by hand.

Feels like I've successfully changed the brakes and not been able to convince myself of something basic.

other cars


https://youtu.be/1t62t5vY_bA?t=721

https://youtu.be/LJc9rzj4hAo?t=2517

[stuart bowes]

Isn't that just the pads in the caliper rubbing on the disc slightly, they always do that a bit, there's no way for them to spring back away from the disc

I suppose you could always take the caliper off and try again with it removed and see if the noise goes away but I wouldn't be worrying about it if it was me

[Darlo 1]

Take it for a drive, apply the brakes a few times but not too hard, there is an anti rust coating on the discs, this will wear off quickly and things will quieten down.

[Roy V70 850]

I always get that sound when I've changed the disc brakes. It disappears after driving the car for a few days. The main thing is that the wheel is spinning quite freely.

[ilmiont]

Originally Posted by stuart bowes

Isn't that just the pads in the caliper rubbing on the disc slightly, they always do that a bit, there's no way for them to spring back away from the disc

I suppose you could always take the caliper off and try again with it removed and see if the noise goes away but I wouldn't be worrying about it if it was me

It was doing it straight after fitting the disc too, without the pads or calipers. Like in the linked videos.

I was just curious what makes the noise as spinning the hub was silent but with the discs on it's like something's touching.

All seems good though. That said I might be pulling the offside apart again as the centre of the disc gained a single score mark in the first 25 miles so I'm wondering if some dust/grit got trapped on the pad surface during installation.

[barrybritcher]

totally normal - dont worry about it

[barrybritcher]

worst case make sure the piston is fully flush back in the caliper

[wynnj]

Check that you haven't bent the back plate such that it's just touching the disk - easily done.