rumbling sound when braking?

I was curious as to what the rubling sound is when i'm trying to break... i mean it breaks fine, just makes this grumbling / rubling sound... The breaks were at 40% last time i had my oil changed (2 months ago)

Well Well Well If it isn't the disk that were cut uneven or they don't have thickens anymore
or break pads are put wrong

same problem...

it was the rear brake pads...

problem solved.

I was curious as to what the rubling sound is when i'm trying to break... i mean it breaks fine, just makes this grumbling / rubling sound... The breaks were at 40% last time i had my oil changed (2 months ago)

-dirt loose
-sticking caliper, fast worn pad
- "abs like" sound: voltage level down to abs computer.

.

But also check whats the min. thickness it can have
also check that the claiper (the one that pushes the brakes) at a time go all the way out and to see if the brakes you put are the same like the ones before