Knock in front end when applying brakes

[pdr01]

Okay guys...at a loss here. I recently upgraded from 16 inch rims to 18 inch rims and replaced front brake pads. Since the upgrade, this noise, a knock, has been getting louder. When I put the car in reverse and start moving, then I apply the brakes, I hear a couple of knocks. Then it no longer knocks if I keep it in reverse and apply the brakes. However, I put it in drive, start moving, apply brakes, then the knock comes again. Its only on the first application of the brakes after switching from drive to reverse or vice-versa. Any comments? I'm thinking it might be the motor mounts? Thanks.

[maurolin]

check torque on the caliper bolts, as well as the lug nuts.

[L84THSKY]

Did you add the plastic center spacers that keep the rims from shifting around?

Originally Posted by pdr01

Okay guys...at a loss here. I recently upgraded from 16 inch rims to 18 inch rims and replaced front brake pads. Since the upgrade, this noise, a knock, has been getting louder. When I put the car in reverse and start moving, then I apply the brakes, I hear a couple of knocks. Then it no longer knocks if I keep it in reverse and apply the brakes. However, I put it in drive, start moving, apply brakes, then the knock comes again. Its only on the first application of the brakes after switching from drive to reverse or vice-versa. Any comments? I'm thinking it might be the motor mounts? Thanks.