Questions about changing rotors

[Brad123]

Hi Guys,

I've replaced my front rotors and was able to do it all with no major drama... or so I thought.

Everything went in fine and worked well, however when the car is jacked up, the front wheels do not spin freely. I am assuming this is not normal, right?

They spin a little but then stop. When turning them by hand, I can hear a soft scraping noise.

It appears that the pads are grabbing the rotors even when the brake is not depressed. What can I do to fix this?

I have taken them apart again, made sure the pads are definitely in the right positions, and regreased the slider pins. The wheel will spin freely until I hit the brakes for the first time, after which the pads seem to remain slightly touching the rotor. The car drives and does not make a squeal or squeaking while driving, however the brakes do smell burnt when I stop.

The pads are also making a banded pattern on the rotors, telling me that they are hitting the rotor unevenly? The odd thing is, they hit the top and bottom, but leave the centre untouched.

Any help or thoughts are appreciated.

 

[Brad123]

My main question is: is it normal for a wheel to not spin freely after new rotors have been put on? and if so, does this go away after the pads and rotors get better acquainted?

 

[greenacc]

There should be no reason for the rotor to stop turning if they are sitting face to face against the bearing hubs.
If you want to test if the pads are rubbing on the rotor you can take the pads out and turn the rotor again, see if it turns freely.
Did you replace the pads when you did the rotors? If they are old pads and the surface are not flat that could cause the problem.

 

[Brad123]

There should be no reason for the rotor to stop turning if they are sitting face to face against the bearing hubs.
If you want to test if the pads are rubbing on the rotor you can take the pads out and turn the rotor again, see if it turns freely.
Did you replace the pads when you did the rotors? If they are old pads and the surface are not flat that could cause the problem.

I did not replace the pads, as they are less than a year old. They are flat though.

The rotor turns freely without the pads in place. It's only after I hot the brake and the calipers close that the wheel stops spinning freely. As in, after releasing the brake the wheel still won't spin freely.

What could it be?

 

[greenacc]

Depends how much it's actually dragging, the calliper piston could be rusty or the seals old and stiff. But that doesn't explain why the pads aren't touching in the middle. They could have worn unevenly on the old rotors. Some people rub pads on rough concrete before reusing them to make sure they are flat.

 

[Brad123]

Depends how much it's actually dragging, the calliper piston could be rusty or the seals old and stiff. But that doesn't explain why the pads aren't touching in the middle. They could have worn unevenly on the old rotors. Some people rub pads on rough concrete before reusing them to make sure they are flat.

Thanks. I'm taking it into the mechanic tomorrow anyway, since I need it done quickly and havent been able to find any answers on the forums. I thought i could just take the old rotors off and put new ones on, but it seems like that has brought on more difficulties

 

[greenacc]

You can, there's not much more to it than that if the pads are ok and the rotors are reasonable quality. Did you squeeze the piston in a bit to make some clearance for the new thicker rotors?

 

[Voodoo_SV6]

If old pads are touching a brand new rotor at the inner and outer edge ands not in the middle, tells me the old pads are not flat.

But also, the fact you start to grab after one application of the brakes means the piston is not sliding back smoothly. BUT a little scrape is normal. If, by hand, you can roll the rotor past the high spot, I wouldn't be worried about that part of your problem. The inner and outer touching is an issue as you don't have 100% of the facr of the pads in contact with your rotor and you'll get less than ideal braking and hot spots on the rotors.

Your mechanic is your frien on this one. Me ... I'd be machining the pads or replacing them

 

[losh1971]

Did you bed them in?

 

[losh1971]

The pads are also making a banded pattern on the rotors, telling me that they are hitting the rotor unevenly?

It almost sounds like hotspots. If that is the case the pads may not have been bedded in properly. If this is it, chances are the rotors have been fried and will need replacing, as eventually they will crack.