If the "knocking" sound is a heavy clicking sound when turning, and if the vehicle is front-wheel-drive, you probably have a worn CV joint, often referred to as a half-shaft.
This problem can sometimes be temporarily corrected by repacking the joint with grease and replacing the rubber CV boot which is probably torn. Usually, however, it is best to replace the shaft since it is necessary to remove it to replace the boot anyway, and this constitutes most of the labor.
On the other hand you can do a bit of a cheat by cutting off the old boot, repacking the joint with grease, and re-covering it with a special split boot that does not require removal of the shaft.
A CV joint (Constant Velocity Joint) is the equivalent of a Universal Joint in the drive shaft of a rear-wheel-drive vehicle.
a dog
possibly your wheel bearing is on its way out
Many causes and different for front wheel drive and rear wheel drive cars. It's hard to say without more detailed information.
Probably you have a bad tie rod (maybe both). You can find it on eBay (around $50.00 L&R). Knocking when turning on front wheel drive is most likely the knuckle on the axle. Look at the rubber boot on the end and I will bet it is split.
Clunking/knocking sound felt though steering wheel and floor when turning and going over bumps at low speeds.
Its Your CV Joint Or Your Wheel Bearing ........... if it is your cv joint you will hear the knocking or clicking sound especially whilst turning corners.xxxx
The cause of the squealing sound is because you are turning the steering wheel completely to the right or left
Make sure the Rack & Pinion assembly bolts have not come loose. Also check the linkage from the steering column to the rack.
A loose or worn belt. Also check the power steering fluid.
u joint
wheel bearings?
many many things, Loose lug nuts which lets wheel make knocking noise. Engine will make a knocking noise if it is really low on oil. Some timing belts make a knocking, slapping noise just before they break.These are just a few examples . Have someone ride in car with you as you duplcate the noise and see if they can determine which part of the vehicle it is coming from.