Groaning / constant hum from brakes

[CSLManual]

Hello All,

Wondering if anyone has experienced this... I seem to have a constant groaning/humming noise when I'm driving around, varying with speed. When I touch the brakes it goes away, and when I brake REALLY hard a few times it goes away for a while and then eventually comes back. What could this be?

I'm fairly sure it's the brakes but I don't know why it would suddenly start doing this.

I have the AP BBK, it also seems my rear pads don't sit tight because they rattle around at low speed. Has anyone had this either?

Thanks

[Mike RT4]

Yes, turned out to be a cracked rear disc for me.

[CSLManual]

Thanks, could you see the crack from a visual inspection (wheels on) or was it trickier than that? I had a look yesterday, it's still humming but I definitely can't see any cracks on the outer faces.

I'll get it up on a ramp this week.

[Mike RT4]

Thanks, could you see the crack from a visual inspection (wheels on) or was it trickier than that? I had a look yesterday, it's still humming but I definitely can't see any cracks on the outer faces.

I'll get it up on a ramp this week.

No, was on the inside face of the rear nearside. It took a while to find as typically the caliper covered it when first inspected as well :bigcry:. Finally revealed itself though after much head scratching and then rotating the wheels.

[CSLManual]

ok thanks... I was hoping these discs would last a while, but (and it's ok, I'm sitting down) what are the prices of replacements for the AP BBK?

[Mike RT4]

ok thanks... I was hoping these discs would last a while, but (and it's ok, I'm sitting down) what are the prices of replacements for the AP BBK?

I was at the Nurburgring at the time, so I just went with standard OE replacements, as I didn't have much choice. The only difference is that the AP's obviously match the fronts (being grooved instead of drilled), but I'm not sure if the APs are as good quality material as the OE discs anyway, as they weren't badly worn, so no real reason for then to crack.

From memory I got charged 900 Euros by Raeder Racing, but that was supply and fit and they also replaced the handbrake shoes, which were shot when they took everything apart.