TRW brake pads

[zedeezd]

I recently replaced the front discs and pads on my 99 Corolla 4afe.Bosch discs and TRW pads were fitted.Lately(after about 3000kms) I've noticed a slight grinding noise each time I brake at low speeds.I inspected the slide pins and caliper pistons and they seem fine.I also checked for any stones or other hard debris but there was nothing present on the pad surface or on the other components.The only issue I could think of are the pads having a harder compound  or something similar which is causing the grinding noise.

Are TRW pads known for making a grinding noise or are the pads fitted defective?

 

[AisinW]

I suggest just to drive it more. Probavly in few thousands miles it will go away.  Bosch and TRW are known brands and they must be certified within OEM spec. Grinding noise on low speed is perfectly normal, that's how the friction should be at the maximum grip. 

I used Zimmermann coated disc and Aisin pads GG rating (highest grip in hot and cold). The coating are gone at the surface where pads meet the disc (as designed). Eventually some pads materials are also embeded on the disc and then the brake finish beaking in.  We get the maximum grip at that point. Consequently, i also hear mild grinding noise at low speeds. Sometimes it squealing in split of second before stop in rainy days when some surface rust built up on the disc.  

What need fixing if: it squeal loudly everytime we brake for long period (bad backing plate/pads) or grabby grinding noise when we are not braking (stuck caliper/pads). 

From MOT measurement, the braking force was up from 390 (old disc/pads) to 570 (fully brake in pads/disc).