Knocking sound when braking had new disks installed no change. Can feel the the brake caliper is a bit loose so I don't know if it must be like that or what.

Any help would be appreciated.

  • Welcome to the site. Please edit your question to include details about the year/make/model of vehicle. Is this driven daily or infrequently? What was changed when the brakes were done? How long ago was that?
    – CharlieRB
    Commented Mar 1, 2018 at 14:10
  • Does it happen when you start braking? Does it continue while you are braking? Does it only happen when you brake going forward after you just backed the car up?
    – jwernerny
    Commented Mar 1, 2018 at 14:32

3 Answers 3


Worn suspension parts can also be a cause of a knocking sound when braking. The "lower control arm" bushings can wear to the point of actually tearing apart, and then the whole front wheel assembly can move back and forth when you brake and accelerate. This will cause knocking when you brake and go over certain bumps. Sometimes the sound can be hard to pinpoint because it will seem to happen at different, unrelated times.

  • How dangerous is it to continue to drive with the said problem with lower control arm bushings?
    – DS R
    Commented Jan 24, 2020 at 14:19
  • @DSR Dalily driving won’t be much of an issue but tires will wear out much faster. The problem comes when you need to stop quick or make a fast maneuver. You will loose some braking and steering precision. For that reason, it is “somewhat dangerous”, and should be addressed as soon as possible. Just drive extra defensively since you know you don’t have full performance.
    – JPhi1618
    Commented Jan 24, 2020 at 14:30

It does depend on the type of caliper (there are calipers that slide on pins that, of course, should move as the pads wear, other calipers are fixed and have two, or more, pistons on each side which move to accommodate the wear of the pads), but the caliper fixing or mounting points should not be loose - do check the fixings usually two large bolts 17mm head or so.

If the pads are excessively loose that can cause knocking as well.


Two causes of brake noise I've experienced and corrected. These could apply to any vehicle with disk brakes:

1) Metallic click one time when applying the brakes. Loud enough to be annoying. Only when moving and going forward; not reverse or standing still. Happens with transmission in neutral, and wheels turned or straight ahead. Cause: Small spring clips that push the brake pad end tabs against the brackets were installed on the wrong end of the pads. The springs should hold the pad ends against the bracket in the direction of rotation when the vehicle is moving forward. Installed wrong, there is a small gap between the pad ends and brackets that closes and makes noise during each forward stop. To diagnose this, inspect the pad / bracket assembly and how the pad ends are being held against the bracket. This was '15 RAV4.

2) Very load clunking when going over rough roads, especially strips on the highway. Cause: Holes in caliper brackets worn, so the caliper sliding pins are slightly sloppy and allow the caliper to bang around. I replaced the pins first, greased them, paid attention to which end got the smooth pin and which got the one with the rubber damper - all without affecting the clunking. Replacement caliper brackets fixed the clanking completely and for years. The original brackets and pins felt OK together, but were not. To diagnose this, lift a wheel off the ground, then use both hands and shake the wheel - if this is the problem, you'll hear it. This was '07 CRV.

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