Knock when applying brakes

[gtdragon980]

Yesterday as I was driving home from the dealership, I noticed when I apply my brakes a knock would occur up-front. It would only knock once as I begin applying brakes, but the car would still brake fine. I was beginning to think maybe the master cylinder is going, but before I buy anything to replace, I would like some other ideas as to what could cause this. To me it sounds more like a knock or a clunk, no grinding or metallic noises. It literally sounds like someone tapped a hammer on the other side of the firewall. Any idea's are welcomed! Thanks!

[immajackuup]

strut bearing is bad,does it knock when you only apply brake???

[jlevie]

Loose caliper or carrier bolts, a bad strut bearing, bad control arm, or bad control arm bushing/mount all all possible causes. Don't drive the car until the cause is identified and fixed.

[gtdragon980]

It only knocks once when first applying the brakes, and each time I apply them. I don't notice it when the car is parked, but if i'm on the move or have been driving for a while and come to a stop, i can tap the brakes at a standstill and still hear the knock. So, from what I recollect from driving it yesterday, it doesn't only knock while moving, it can be at a stop and still knock. Maybe air in the system?

[jlevie]

Since you can cause the noise with the car not moving I'd look to the caliper or carrier (or maybe wheel bearings). I don't see how air in the system could cause noise.

[gtdragon980]

Okay, when I get off work I'll take a look. Will report back.

[gtdragon980]

Well, after driving it yesterday I found out that it is in fact either the ball joint or the CAB. The knock only occurs while the car is moving, and not when it's at a standstill unlike my previous description. Not only that, but the same knock occurs when hitting bumps and it is centered right around the driver wheel.

[oxymoron]

this happened to me, found out my brake pads and sliders were bone dry i hit them with nice brake paste and it stopped

[Northern]

Happened to me a week ago as my wheel was about to fall off. Only difference was I also experienced a vibration at 60kph+

[lambo]

Shock mounts, maybe?

[KenC]

So your caliper and carrier bolts are all tight?

[acolella76]

don't brake?