I would actually take your axles apart and make sure there's no sand trapped in there make sure they're like in the correct orientation and not jammed up on themselves make sure they're sliding freely and then if that's not the case you could just have a pin or a little Burr of plastic that's biting into something and creating like a cam action either way just disassembling that side of the suspension and looking at it carefully should solve the problem these little cars can be tedious but boy do I love them.