During the normal operation of your vehicle your car is going to make some sounds that you should be used to hearing. When your car is working the way it's supposed to you should hear a hum from the engine but little else should be happening as you drive. If you're noticing various grinding sounds, squealing sounds, clunking, banging and knocking noises then those are all indications that something has gone wrong with your vehicle and you're going to need to have it checked out to figure out what's going on. In particular if you notice a knocking sound from the front wheel when you're driving there are a handful of reasons that you can look into for why this might be the case. Let's take a look at the most common reasons and what you can do to get your car running silently again.
1.Problem with the Struts
Your vehicle's suspension relies on struts that are attached to your vehicle by something called the strut mount. The purpose of this strut mount is to reduce the sound and vibration that the tires create as your vehicle is in motion as well as reducing how the vibrations transfer from the wheels through the entire frame of your vehicle. This in turn helps stabilize your ride so that you don't really feel every single bump and variation in the road under you as you travel.
If your struts or your strut mounts begin to wear out or sustain enough damage, then their ability to both eliminate noise and reduce that vibration is going to suffer greatly. Broken struts can create a knocking sound that will be most noticeable when you are on rough roads. If you're hitting potholes or bumps, you will definitely notice a loud knocking or clunking sound as a result.
Replacing the struts on your vehicle can be a rather expensive repair job overall. New struts typically cost somewhere between $600 and $750 to get done.
2.Ball Joint Problems
The wheels on your car are attached to the suspension system by some ball joints. The ball joints are necessary for your wheels to have a proper range of motion which allows you to turn left or right when you turn the steering wheel. When these joints begin to wear out then you're going to hear a grinding or knocking sound as you make adjustments to how you're driving with the steering wheel. The noise will be especially prominent anytime you make a full turn either to the left or to the right. If it is bad enough you will still notice it even when you're just making slight adjustments as you're driving in a straight line.
If you need to replace the lower ball joint on your car you will probably be facing a repair bill somewhere between $300 and $350.
3.Bad Wheel Bearings
Wheel bearings are what allow your tires to spin freely and smoothly while the vehicle is in motion. If the bearings begin to seize up or they get dirty and that prevents them from doing their job properly then you're going to be experiencing grinding and knocking sounds while you're driving. If the situation gets bad enough your wheels can actually lock up on you and not work at all.
If you need to replace the front wheel bearings in your vehicle then you're looking at a repair job it's going to cost you probably between $250 and $500 depending on the make and model of your vehicle.
Part of keeping your entire driving experience smooth and even is making sure that your tires are balanced and properly aligned. If you have severely misaligned tires or something in one of your tires has actually broken, then every time it rotates and hits the road it's going to create a noticeable bump or a knocking sound. If the tires are still in good condition, then a proper alignment should be able to eliminate this for you.
Getting your wheels aligned is one of the cheaper maintenance jobs you can have done in your vehicle. Typically, you can expect to pay anywhere between $65 and $100 to get your wheels aligned these days. Front end alignment is actually the cheaper option which will fall in this price range. A rear alignment would cost a little bit more.
5. Bad Bushings
The bushings are in place in your suspension system to help keep your vehicle properly aligned. They stabilize parts of your suspension and wheels to keep them in check. Bushings are typically just made of rubber so they will wear down over a long enough timeline, especially if they're under a lot of stress. When your bushings wear down far enough or they actually break you're going to hear a knocking sound caused by metal parts hitting against one another without the bushings there to buffer them any longer.
If you need to replace your lower control arm bushings, you're probably going to have to pay somewhere between $450 and $500 to get the job done.
6. Axle Problems
The axle at the front of your car is what both of your front tires are attached to and it handles the weight of the entire front end of your vehicle. Typically, your axle will last the life of your vehicle and should be sturdy enough to maintain itself without you needing to worry about maintaining or repairing it in any way. However, the axle is susceptible to damage sometimes especially if you hit a bad pothole or some kind of junk in the road that gets caught on the axle. Additionally, it's not unheard of that an axle can be the victim of a mechanical failure caused by an issue during manufacturing. There have been a number of vehicles recalled for just this reason over the years. When that happens the axle is not able to handle the stress that's on it and it will eventually bend or break as a result.
Unlike some parts of your vehicle, a broken axle absolutely cannot be repaired. If it's bent as well it is essentially useless because you can never bend it back into place again. It will always be weak and when that happens your tires will not be able to hit the road evenly any longer. This can lead to uneven tire wear, problems turning, knocking sounds, and potentially the axle breaking completely, leaving your car undriveable.
If you need to get a new axle shaft installed in your vehicle because yours has been bent or broken, then the price can fall in quite a wide range between $500 and nearly $1,000. It's possible you can find a front axle for a bit cheaper than that as rear axles tend to be the more expensive ones to get fixed. Front axles may only cost you somewhere between $500 and $600. Still quite pricey but not nearly as expensive as the rear axle.
7. Loose Lug Nuts
The lug nuts are what keeps your tire on the wheel of your vehicle and what you need to remove if you're changing out a flat tire. If you've recently swapped out your tire, either because it was flat or even just because you had your tires rotated, then perhaps the lug nuts were not properly retightened. If your tire isn't properly secured to the wheel then it's going to wobble when you drive, a situation that will get worse the longer it's allowed to remain loose or the faster you go. When it gets bad enough it can produce that knocking sound that you hear when you're driving. If you're not careful you could potentially cause some serious damage if you drive your car for too long in this condition. It's possible the entire wheel itself could come loose and fly off while you're driving. That could be a danger to you as well as anyone else on the road. If you notice that your lug nuts are loose you need to get them tightened right away before trying to drive your car again.
If you actually lose a tire while driving the cost of replacing it is hard to gauge because the nature of why the tire came off in the first place needs to be taken into consideration. If it was just a matter of the lugs coming off and the wheel itself is still in good condition then all you have to do is replace the tire which would be the cost of a new tire. However, the odds of your tire coming off while you're driving and no damage being done to your vehicle are slim to none and the entire situation would need to be assessed before an estimate of the repair cost could be made. It's possible that this kind of accident could cause damage to not just the wheel itself but your brakes, your suspension, the axle, and even the body of your vehicle as the tire flies off.
8. Bad Control Arm
The control arms on your car move up and down with your wheels as you go over uneven roads. They are integral for keeping your vehicle steady as you drive. Basically, they keep the tires on the road by compensating for the variance in road whether that be potholes or bumps so that your drive can be as even and smooth as a possibly can be. If you have bad control arms your ride is going to be extremely rough and bumpy, and your tires may actually bounce off the road as they go over uneven terrain. This is definitely going to lead to not just an uneven ride but some knocking sounds as well.
Broken or damaged control arms are not a cheap repair job by any means. You are looking at a repair bill that's going to be somewhere between $500 and $700 on average to replace the lower control arms of your vehicle. In some cases, depending on the make and model of your vehicle, the repair bills could get up over $1,000 for this kind of job.
9. Broken Sway Bar
Sway bars are part of your vehicle's suspension that prevent rolling when you take corners. If you didn't have a functioning sway bar it possible you could actually flip your car over if you took a corner too fast. Because they're under a lot of stress when it comes to balancing the weight of your vehicle from one side to the other they're prone to breaking. When the sway bar does break it could lead to a knocking sound that you hear at the front of your vehicle.
If you need to get the sway bar in your vehicle replaced either because it's worn out or it's been damaged it will likely cost you somewhere between $125 and $175 to get the job done at a mechanic.
The Bottom Line
The sounds your car makes are one of the first and most noticeable signs that you're going to get when there's a problem with your vehicle. You need to be aware of how your car sounds when it's operating under normal conditions so that you could also be aware of the sounds that it makes when something has gone wrong. In many cases when you first start noticing the sound coming from the front of your vehicle when you're driving, you'll have time to do something about it before it goes from bad to worse. But you do need to pay attention to when these sounds arise and you do need to make sure you're getting into a mechanic as soon as you can so that you can have the problem addressed and you don't need to worry about an inconvenience turning into something much more serious down the road.
As you can see there are a host of reasons why you might be experiencing a knocking sound from your front wheels while you're driving. Very few of these are the sorts of things you want to ignore for too long. If you're experiencing these kinds of sounds right now do yourself a favour and get it looked at before you end up in an accident and hurting yourself or others on the road.