loud hum coming from the front tires when driving on highway

ANSWER : Hello. The brake caliper hanging up can cause the noise you are hearing. If the caliper is causing the brake pads to drag, this will occur. It can also be caused by a bearing failing, which will cause the noise and the caliper to hang up. Most commonly though, it is caused by a tire that is wearing unevenly. If the tire has some odd wear from lack of rotation or from a worn out strut, then this noise can happen. I usually check the tires first and even cross rotate them to see if the noise changes. If it remains the same, then the tires are not the issue. If the shop does not fix it correctly, consider YourMechanic, as a certified mechanic can come to your home or office to diagnose the noise and let you know exactly what’s going on.

ANSWER : Hello, thank you for writing in. Chances are there was an existing issue that was amplified by the tire rotation. There are several parts that will cause similar symptoms. You will want to consider the parts that are under load in 4wd, that are free when in 2wd. This would include the axle and sveral joints. There are a couple of tests that can be done. More damage was likely done driving on dry pavement in 4wd. It was a good step in diagnostics, but should be avoided. For more help with diagnosing the sounds, contact our service department to schedule an appointment.

ANSWER : Anything is possible with enough engineering. The changes you are looking at would take major structural changes and would definitely not be an easy job. You could possibly consult a manufacturing engineer to get more details on how this could actually be carried out and whether it would be feasible.

ANSWER : A clicking noise on turning is very characteristic of a failed outboard CV axle joint. Sometimes, in such a circumstance, you can see that the rubber outboard boot is actually torn and leaking grease. If you see that (look behind the wheel toward the axle end), the axle for sure will have to be serviced. If you change the axle, be sure to install a new rubber seal on the transmission output side so that you do not have transmission fluid leaks with the new axle (a common mistake is to overlook that seal; if an old, left-in-place seal leaks after the axle is put in the job has to be done all over again). Vibration without actual shaking of the steering wheel "might" be related to the axle issue. On the other hand, such vibration could also be due to a failed wheel bearing, especially with over 200,000 miles on the vehicle and if those are the original bearings. If you were to need both an axle and a wheel bearing at the same time, and on the same side, that’s actually not that bad because the steering knuckle that holds the wheel bearing has to come off anyway to replace the axle. But, backing up here, the very first thing to do is get the issue properly diagnosed so you spend the minimum possible. If you want to obtain a diagnostic, please request a vehicle CV/wheel bearing noise inspection and the responding certified mechanic will get this taken care of for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

ANSWER : The wheel hub bearing could be getting noisy or the scraping noise could be caused by the brake pad material. The most common cause of such noise is when the metallic material in the brake pad makes a scraping noise when brakes are not being applied and then it becomes noisier when the brakes are applied.

Bad or faulty lower control arm bushings will cause the noise to resonate through the frame and body of the car when compared to good rubber bushings that would normally isolate most of the noise.

First, get a certified technician, such as one from YourMechanic, to replace the control arm bushings and check the brakes for any cracks in the brake pad material and excessive metal material in the pads that can cause the noise. At the same time, get the wheel hub bearings checked for noise and replaced, if necessary.

ANSWER : Unfortunately, many sports cars will experience some inner edge wear on the front and sometimes back tires as well. This means that the vehicle has positive camber designed into the suspension. When a vehicle has positive camber designed into the suspension, this will enable the vehicle to take corners better and will provide some more stability during harsh manuvers. If you are very concerned with the tire wear, I would recommend having your vehicle aligned out of specification to make the wheels more towards the zero mark on the front camber. This may however affect the way the vehicle handles and is not recommended under normal circumstances.

ANSWER : Hello. There are a few things that this can be. Most of the time it is due to a failing front bearing. When a bearing fails this noise will occur. I typically get the vehicle in the air and spin the wheel while listening for the noise and then disassemble the bearing and inspect it. If it is fine then the noise may be a brake caliper or pad that is coming loose or a failure in the front differential. If you need to have this looked at, consider YourMechanic, as a certified mechanic can come to your home or office to diagnose this.

ANSWER : Hello there, many different faults will cause a humming noise from the front tire of your 2008 Kia Optima. The most common would be a failing tire, wheel balance, wheel bearing, dragging brake pad, sticking caliper, or a CV axle issue. A qualified technician, such as one from YourMechanic, will be able to diagnose your humming noise and perform any repairs required to get the car back to normal.