What Is Hub Assembly?
The steering wheel hub assembly is essentially the mounting assembly for the wheel of a vehicle. It is interchangeably also known as a hub assembly, wheel hub unit, wheel hub bearing etc. It includes the wheel bearing as well, as the support lugs.
In most of the newer vehicle models, you may also find a speed sensor, and ABS sensor attached to the unit via an electrical connector. The job of the wheel hub is to keep the wheel spinning freely on the wheel bearing. The wheel hub is the main component that holds the wheels to the car, and hence is very crucial to the vehicle. In this article you will learn more about its location, functionality, and even how to install one on your own.
Where Hub Assembly Is Located?
You can find the wheel hub assembly located between the brake drums/discs, and the drive axle. A wheel is basically bolted to it. A roller bearing is present between the axle hub and the axle shaft, which ensures easy rotation of the non-drive wheels. On the axle side, it will be mounted to the holding bracket from the chassis on the disc side the wheel is mounted to the bolts of the wheel hub assembly.
On the axle side, it is mounted to the holding bracket from the chassis; on the disc side, the wheel is mounted to the bolts of the Wheel Hub Assembly.
How Do Hub Assembly Work?
One has to know that the hubs of the driven wheels are different to the undriven ones, even though they look similar. They are constructed in a different manner because the drive hubs incorporate drive shafts too.
In the case of a front-wheel-drive car, the hub has to perform two functions, one is to drive the wheels and the second is to swivel so that the car can be steered. In order for this to be possible the hub rotates in or next to a huge casting which is known as the hub carrier. This carrier itself is mounted to the suspension via ball joints which allow it to swivel, as well as move up and down as per need to move on the road smoothly.
The cars with MacPherson struts have a different scenario. In these cars, the hub carries has a ball joint present at the bottom, which is either bolted to or is a part of the strut at the top. The upper swivel is formed by the struts top mount where it joins the inner wing. How much the hub carrier can swivel will be controlled by the steering gear. Which has the steering arm attached to it via another joint.
Symptoms Of Bad Hub Assembly
Following are some of the symptoms that show that the wheel hub assembly is not in its proper condition:
- Roaring sound coming from the tire / wheel area - A poor wheel hub assembly can be caused due to the wheel bearing inside theassembly getting damaged. You can pick roaring, or metal to metal grinding sounds too. This is because of poor lubrication inside the bearing. It can be rather difficult to determine by sound which bearing has gone bad and which one is fine. But if the side wheel hub assembly is broken, then both sides on the same axle will have to be replaced at the same time.
- Steering wheel vibrates or feels loose - Damaged wheel hub assembly can cause the steering wheel to feel loose, this can be especially noted in low speeds and when accelerating from a low speed. The steering wheel in turn will vibrate, you can be observant about when this would happen more, as it increases when making turns or maneuvering through dips in roads.
- Tire / wheel combination has a lot of play when in the air - This can be picked up only by a certified tire mechanic. When the vehicle is on a hydraulic lift or jack stands and the tire/wheel combo is firmly attached to the wheel hub assembly. In such a case if the tire wiggles from left to right or even up and down when pulled, it will indicate a broken wheel hub assembly and will warrant replacement.
- Clicking sound from the wheels - During acceleration if the clicking sound comes, it could be due to a problem with the wheel hub assembly. A broken wheel hub assembly will cause the brake caliper to move up and down and in doing so hit the top of the wheels, when the vehicle moves.
Tools Needed For Hub Assembly
Are you thinking of repairing your Hub Assembly on your own? Then there is one thing which you must have, that is the right tools needed for repairing your Hub Assembly. It is essential to make sure that you are outfitted with the right tools to get the work done properly. Have a look at some tools which you might need to get started with your repair work:
- ⅜ drive ratchet
- ⅜ drive socket set - metricand standard
- ⅜ or ½ drive torque wrench
- ½ Inch drive breaker bar
- ½ Inch drive wheel socket set
- ½ Inch drive metric andstandard socket set
- Disposable gloves
- Floor jack and jack stands
- Pry bar
- Allen set metric and standard sockets
- Axle nut socket set
- Brass hammer
- Combination wrench set, metric and standard
Top Brands For Hub Assembly
When it comes to vehicle owner’s choice, the brands really matter a lot. You might pay a premium for a specific car part brand, over time, as it has created a perception of quality, stability as well as trust. There are some leading car parts brands which are more than just products or services as they give rise to memories and emotions related with the quality. So have a look at some top brands for Hub Assembly.
Total System Costs & Repair Times, Effort Of Hub Assembly
I bet that you’re thinking as to how much does a Hub Assembly replacement cost. Just keep in mind that it is not as easy as putting a fast and hard number on it. This is because the replacement/repair cost would be different for every Hub Assembly and it would also vary depending on how in-depth the repair needs to be. If you are thinking about the exact cost, then you might take help of an expert mechanic. The average cost for a wheel hub assembly replacement can be approximately between $905 and $1001. Labor costs can be roughly estimated to lie between $143 and $181 while parts can range anywhere between $762 and $820 approximately.
How To Change Hub Assembly?
You can find the steps for replacing the wheel hub assembly here:
Step 1 - Work area preparation
Ensure that the vehicle is on a leveled safe surface, and is set in parking brake. Gather all your tools and manual if needed for reference. Make sure the manual is for your exact vehicle make and model.
Step 2 - Loosening the lug nuts
Using the ½ inch drive breaker bar and a lug nut socket set, loosen all the lug nuts and axle nuts (if applicable). This has to be done before you jack the vehicle up in the air.
Step 3 - Jack up the vehicle
Use jack stands to do this and place the wheel off to the other side, away from the work area.
Step 4 - Removal of the old wheel hub assembly
Start by removing the axle nut (if present) and then disassemble the brakes by removing the caliper and bracket bolts. Now you can remove the rotor. Check if the vehicle has anti-lock brakes, if it does, then disconnect any wiring harness plugs. You can now loosen all the bolts which are holding the assembly onto the knuckle. You should be able to remove the whole wheel hub assembly as a unit once this is done.
Step 5 - Install new wheel hub assembly and brake parts
You can now trace back from steps, start by bolting the new wheel hub assembly to the knuckle. Be careful and connect the ABS sensor connector if it was present. Torque the bolts as per vehicle specifications. Install the roto back, and start reassembling the brakes. Now you are ready to install the brake bracket back to the knuckle. Torque it and then install the pads and the caliper back onto the bracket. Reinstall the axle nut (if needed).
Step 6 - Reinstalling of the wheels
Using the lug nuts place the wheel back onto the hubs. Carefully snug them down using a ratchet and socket.
Step 7 - Jack the vehicle off the jack stands
Using the same jack, place it in the correct spot under the vehicle. Jack up with car till you are able to remove the jack stands. You can now carefully lower your vehicle onto the ground.
Step 8 - Torque the wheels
Use a ½ inch torque wrench and torque the lug nuts to the proper specification. A lot of the cars use a torque from 80 ft lbs. to 100 ft lbs., the SUB and trucks will be higher. So, it’s important to refer your specific vehicles manual for the information.
Step 9 - Test drive
Pump the brake pedal a few times, this will help the brake pads to reseat to the rotor. This is important as you took apart the brakes for replacement. Pay attention to any noises that may come from the hub bearing. If you hear no sounds, this will be a sign of a successful replacement.