Excessive brake drag on front rotors? (searched)

[Hype]

Just thought of this today while the front of the car was raised while working on the clutch slave cylinder -

I understand that disc brake pads ride very close to, if not very slightly on the surface of the rotor, but how much is normal? I can turn the wheel with the grip from just my thumb and pointer finger, but it wont spin after I let go.

92 240SX, stock brakes btw.

[MaximA32]

It's not supposed to spin freely. If it did spin freely then you would have a problem.

[Hype]

Thanks for the reply. I know it's not supposed to go round and round all on its own, but I wasnt sure if it was TOO tight.

[ianh]

Yes this drag is normal.The pads are knocked back by the rotor moving on the bearings a few thou.So you have to drive the car to get some clearance, and stop without using the brakes !! then check it.Only exception to this that I know off is the double cylinder Dunlop brakes on the 60's Jaguars, they have a pull back mechanism, this pulls the pads off the rotor by 5 thou or so.

[Hype]

I redid all four corners with Hawk HPS and Brembo blanks last summer along with brakestop ss lines from pdm-racing. I'm still not entirely satisfied with the brakes, so I'm thinking the fronts should be rebuilt. The rears are remans but I'm not happy with those either The systems been bled well (I just replied to your post in my other thread about speedbleeders), I think its time to put some new seals on the calipers. I suspect them dragging slightly too much while clamping just too little... heh

[ianh]

Well if the piston moves when you replace the pads the forces are so great when being actuated i don't think its an issue, if the piston is frozen you will not be able to move it.Re your comment about not stopping well enough. I put the bigger disks and calipers on my Sentra, and purchased Raybestos loaded calipers. No idea what the p[ads were other than Raybestos.When the pads wore out I purchased "in stock" semi metallics from Autozone. ( Ok I can hear the groans from here!!) Well the damm car went from over sensitive and stopping super well to nearly running lights when it was cold and or wet.Apparently this is an issue with the new compounds with high ceramic content.So I was recommended different pads to try that bite better. Put the rears on, fronts still to go.So i suggest a change of pads, worth a try anyway.

[Hype]

I was more referring to pedal feel then stopping power. I had OEM pads before with tired, rotting old rubber lines. This setup is certainly way better and I couldnt be happier with the pads. Hawk HPS pads are quiet, arent tempramental in cold stops and resist fade really well. I'm just a perfectionist, but I dont think a big brake swap is warranted on this car... yet Just trying to get all I can out of the current setup.

Well the damm car went from over sensitive and stopping super well to nearly running lights when it was cold and or wet.Apparently this is an issue with the new compounds with high ceramic content.

Brake pads (especially performance pads) bed into the rotor so if a different pad is used, the rotor should be scrubbed and rebed. It's as if the pads make a chemical imprint on the rotor. The mating of the pad to the rotor has a lot to do with the quality of bite your brakes will have. There's a recommended procedure that basically involves heating up the pads with a few brisk stops followed by a cooling period and finally another few stops. There is a good article on Stoptech's website about it.