Brake Caliper tapping

[Robbo]

So, I've developed a constant tapping of the brake shoes against the caliper while I'm driving. It's interesting because the pads are fairly new, they are not complicated and they all function properly to stop the vehicle. Anyone have experience with this? Almost like either the driver's side rotor is warped or the pads are a little small. Open to ideas.

 

[puff4]

Pad rattling is not unusual in the Alpines.

To minimize it, make sure you have the proper pad shims (anti-squeal kit) installed and that your pad pins fit tightly in the caliper and pads. It's harmless but annoying.

 

[Robbo]

Spent some time on this. Replaced the shims and tightened down the bearing nut that was a little lose per Al's suggestion. Sure enough, that was the trick. Thanks as always gang for the suggestions. I am a "rattle chaser" which on these Alpine beauties could drive a man crazy!

 

[sunbby]

I have a similar symptom on one side. Which bearing nut, assuming you mean the castellated nut for the front hub? How loose was it was there noticeable play in the front hub?

 

[puff4]

The nut being discussed is the front wheel hub bearing castellated nut. Making it tighter takes up any bearing 'slop' in the front hub bearing and thereby prevents the brake disk 'wobbling' and knocking back the brake pads.

It is *very* important not to overtighten this bearing, however, as it can be damaged by being too tight. It is critically important to have a small amount of play in the bearing.

To properly adjust it, put a dial indicator against the top or bottom edge of the bearing flange and wiggle the brake disk top-to-bottom, watching the indicator. You're looking for no more than .007" and no less than .002" in total play. Tighten the castellated nut until you get the minimum play.

If you don't have a dial indicator you should tighten the castellated nut until you can just barely feel a very small bit of play in the bearing. The way I do it is to tighten the hub until very snug... rotate it a couple of times... snug it down again... rotate again... snug it down again... rotate again... and then very slowly back it off until you can feel that slight bit of play. (Note that by 'snugging down' the nut I do NOT mean 'crank it down'... I mean just make it tight without applying much torque.)

In either case, be sure to rotate the hub several times, checking for play several times a long the way to be sure it stays consistent.

Don't forget to re-pin the castellated nut with a new cotter (split) pin. If you have to move the nut to insert it, it's always better to back off than tighten.