Knocking sound only in wet conditions

[Jameskixg]

Hey all I’ve got a 2016 np300 & every time when it’s wet it has a knocking sound when I take off & that’s it. It only ever happens when it’s wet & it’s fairly loud. The sound is coming from the front right, thinking maybe the ball joint? Any ideas/ suggestions are appreciated

 

[Old.Tony]

I really can't see how your ball joints would act differently on a wet road (under light or mild acceleration). Under hard acceleration I could see the safety systems (anti wheel spin stuff) doing something. Loose ball joints can easily be felt by shaking the tie rods - give that a shot.

 

[KevinE]

I've just been through something similar with my wife's Pajero; it's a process of illimination. My first thought was a shocker was failing, but nope (although that may or may not be your problem though)

Took it to a mechanic, who diagnosed worn LCA bushes. His advice was to replace the entire LCA assemblies (Edit - including ball joints). We did, it was expensive & it didn't work (once again though, it may or may not be your problem)

I was sctratching my head & thinking of replacing the UCA's next, then I took it to another mechanic to see what he thought before I did.

He came for a drive in it & heard the knock, then said to try replacing the brake pads, as they were old (but still had plenty on them) & according to him, old pads sometimes wear & move a tiny amount in the caliper when taking off/stopping, causing a knock. It was cheap, so why not!

Bingo! That fixed our knock. Good luck with yours.

 

[KevinE]

I really can't see how your ball joints would act differently on a wet road (under light or mild acceleration). Under hard acceleration I could see the safety systems (anti wheel spin stuff) doing something. Loose ball joints can easily be felt by shaking the tie rods - give that a shot.

It could be traction control causing the brakes to grab during tyre slippage on a wet road. In turn, making any worn parts knock?

 

[Old.Tony]

It could be traction control causing the brakes to grab during tyre slippage on a wet road. In turn, making any worn parts knock?

Yes, for sure. Wheel slip can do weird things when the car's trying to fight it.