Earlier near the end of April my daughter brought to my attention some problems with the car. Aside from the cracked windshield and the failing power lift gate, the car started making a clunking noise when turning. The noise wasn’t very noticeable at speed but it was obvious at low speed turning. I ended up giving my daughter the loaner car so I could get the Santa Fe up on the lift for repairs.
Investigation
As with any project I do, I usually need to educate myself on the mechanics of the car. The following diagram illustrates the components of the car’s wheel and axle system.
The moving parts involved that typically fail are the bearings on spinning parts, ball joints, struts and bushings.
- Ball Joints – these connect the wheel to the control arms. There are usually an upper and lower control arm. There are 3 ball joints that could be compromised. Usually you can tell a bad ball joint through visual inspections. If the rubber boot is ripped, the joint needs to be replaced. If the joint is easy to move around, it needs to be replaced.
- Sway Link – this part connects the sway bar to the bottom of the strut assembly. The joints on the sway link are similar to the ball joints and the same troubleshooting options.
- Sway Bar Bushing – this is a part made of rubber that insulates the sway bar. Sometimes older cars have degraded rubber or none at all. If the rubber looks good and solid the bushing does not need to be replaced.
- Wheel Hub Assembly – This part connects the wheel to the control arms and CV Axle. It is a spinning part and when the bearing begins to break down the car will make noise which grows louder with speed.
- CV Axle – The Constant Velocity axle transfers power from the transmission to the wheel. This part is designed to flex with the steering angle and up and down motions from the road. Visual inspection can usually be enough to determine if this part has failed. If the boot is ripped or grease is all over the area, the cv axle needs to be repaired. Another sign of a bad cv axle is noise that is produced when turning the car.
- Steering Knuckle – This is the part that connects the wheel’s left-right swing action to the steering wheel assembly.
After viewing several videos and inspecting the wheel I believe the problem is likely the CV axle.
Removal
To get to the CV axle part I will need to remove the wheel & tire, remove the brake caliper, remove the wheel hub assembly from the CV axle via the wheel spindle nut and remove the wheel hub from the strut.
I’ve had experience replacing brakes and suspension but I’ve never had to actually remove the wheel hub assembly or a CV axle. What I didn’t know is that the spindle nut, which is responsible for holding the wheel to the CV axle, has a safety feature where the spindle nut is pined or secured via cotter pin.
This must be removed using a tool like a chisel punch. The nut cannot be removed without bending the outer wall back into it’s original form. Trying to remove the nut as is will result in damage to your CV axle spindle.
I spent about an hour working on removing the spindle nut but I did so without causing any damage to the original CV axle. Interestingly I learned that sometimes the CV axle is called a half shaft and mine was a short CV axle assembly that plugs into an extension called the bearing bracket shaft. I visually inspected this part and there weren’t any obvious problems with the original.
I removed the CV axle using a crow bar and gently separated the black bottom part shown in the image from the bearing bracket assembly. It was quite easy to pull out. There are specialty tools designed for removing axles. These tools are called a CV joint fork and a slide hammer.
With the part out of the car, I inspected the unit. There were no cracks in the rubber boots and there were no sounds made when I manually manipulated the angle of the joints. It’s not a smoking gun but it is the most likely problem given the physical sounds I experienced when riding in the car before starting this repair job.
I ended up ordering the CV axle assembly and a new wheel hub hoping that replacing these parts will solve the noise. As I mentioned earlier, there was no obvious damage to these parts. The most common failures involve a tear in the rubber boot allowing access to the inter bearings. These boots both look fine. In addition I manually manipulated the CV axle but was unable to replace a noise. The only thing I couldn’t replicate manually is the weight of the car on those bearings. The wheel hub doesn’t have any flexing parts so it’s also unlikely to be the problem but as a $50 part, I figured why not just replace the part.
Note: Ordering parts online is not necessarily an easy process. There are many options and not every parts website had all the parts I needed. I ended up buying from Parts Geek and I unfortunately selected the wrong wheel hub assembly. The part was off by just a few millimeters but might as well have been a country mile.
Before I move onto the installation process I want to touch on the other components and what I did to review their condition. I ended up removing the strut assembly to check on the condition of the top of the unit that is bolted in under the engine compartment. These units can fail and wear out. I have changed out the front suspension on other vehicles and I didn’t think this car had an issue but I just wanted to make sure there wasn’t anything going on where I couldn’t see. While taking this part out I also looked at the sway link. These ball joints can fail but these didn’t have any visual wear and there wasn’t any in/out movement or very easy movement. That suggests the part is ok. I also tugged on the steering knuckle for excessive movement, there was no movement at all. The other ball joints on the control arms all look okay. I think I’ve looked at these parts in debt 4 times now. I’m satisfied that these parts are not the problem.
Installation
The installation process requires the CV axle to be installed before attaching the wheel hub assembly to the control arms. The reason is there are splines on the ends that insert into the bearing bracket shaft and the wheel hub assembly. I was unable to install the wheel hub assembly due to the sizing mismatch between the bolt holes on the part I bought and the bolt holes on the control arms. After calling Partsgeek and working with one of their advisors I went ahead an ordered a second wheel hub assembly. As it turned out that part also didn’t quite fit. It was so close but again, no cigar. I decided to reinstall the old wheel hub because it didn’t demonstrate any of the traditional signs of damage.
It seems the proper term for the receiving part of the bolts is called a knuckle. As you can see in the diagram the four bolts will need to be torqued 78.5 – 98.1 NM. Secondly the brake disc has two screws that insert into the wheel hub. These screws require a torque of 4.9 – 5.9 NM. These screw by themselves do not hold the brake disc to the car. The bolts protruding from the wheel hub are actually the lug nut bolts that the tire mounts onto.
These are additional torque specs for the front suspension. Since I didn’t remove the actual strut the only specs I need is for the ABS sensor. It’s interesting how that sensor works. Just outside of the wheel hub assembly there is about 3/8in wheel with teeth, like a cog wheel. There are 52 teeth on the wheel. The ABS sensor scans the teeth passing by and when the brakes lock the wheel, the teeth stop moving too and that is how the sensor knows to trigger the ABS feature which releases the brake pressure allowing the wheel to spin freely again.
After applying the proper torque to the various bolts mentioned above, the final step to assembly was to replace the tire onto the wheel. At this point I believed I had solved the problem. I took the car off the lift and drove it around in my parking lot in circles. The sound that I remembered was gone. There was still a periodic clunking sound that I couldn’t really identify. I was a little worried there was more work to do. It wasn’t until I took the car onto the road for a drive that I realized I had not fixed the problem. The difference though is the sound appeared to be coming from up higher, perhaps the top of the strut assembly? Back to the drawing board.
Struts and Shocks
After doing some more research I ran across a youtube video that demonstrated the same sounds I was hearing. The video labeled “Worn-out Strut Noise (LIVE)” triggered me to think I need to replace those struts. The car is a 2017 so it’s about the time for a new suspension anyways. The front of the car uses a combination of a shock absorber placed inside of the spring coil that is contained within the strut. These parts can be replace individually but it is dangerous work because the spring is under compression. If not managed correctly the compressed spring can suddenly release causing major harm or even death. The alternative is to buy the entire assembly. Plus since I would be working on the car, I might as well replace the back shock absorbers and sway links. I ordered my parts from Rock Auto this time, hoping to avoid the crappy experience I had with Partsgeek.
Removal of the strut assembly is similar to the process I used for the wheel hub assembly, except instead of taking apart the wheel we simply remove the two bolts that connect the strut(#3) to the knuckle (#2).
There is a small bolt that secures the brake line and ABS sensor wires in place that also should be removed to allow the knuckle to drop out of the way.
Lastly there are three bolts that connect the top of the strut (#10) to the frame of the car. Those bolts are accessed via the engine compartment.
After removing the passenger strut and comparing that to the new one, I noticed a problem. This is my smoking gun. The picture on the left is the new strut. The picture on the right is the old strut that was removed. Notice the slight angle at the bottom of the old strut. That is not normal. That is a bent strut. The force required to bend a strut must be intense. Something happened, perhaps a pothole has hit at high speed?
Installing the new strut is pretty easy. The most difficult thing for me was holding the part in place while I tried to fish the mounting bolts up through their tiny holes while simultaneously trying to reach my hand into the small space to screw on the nut. I ended up using a rachet strap to hold the strut in place while I screwed in the first bolt. The second and third nuts are much easier to install because gravity is no longer working against you. The torque specs for the strut assembly we mentioned earlier.
Moving on to the back of the car, I decided to go ahead and replace the shocks so that the full suspension would be new. Shocks wear out over time. These were all in pretty good shape but like I said, since the car was on the lift, I might as well do the work. Later I would regret that decision.
The back shocks work a bit differently. There is no strut involved on this car. Just a shock absorber (#1) that bolts into the frame of the car using a non-standard bolt (#2) and inserts into a pin at the rear wheel knuckle (#3). This procedure is a bit easier than the front strut but there is danger here.
There is an old saying that I’ve heard, “If it ain’t broke, don’t fix it”. I understand the phrase now. I’ve replaced suspension on cars before and I’ve always thought that the rear shock replacement was a lot easier than the front strut assembly. Perhaps my confidence was partly to blame for the mistake I made. During the installation process I damaged the Shock Upper bolt and its mount hole. Somewhere along the lines I cross threaded the bolt. I learned from my research that this is not an isolated issue. Many people have had issues with the treading on the mount hole.
The first image shows the Shock Upper bolt and the cross threading is evident at the tip. The threads are no longer sharp but appear rounded. The mount hole is the image on the right. It’s hard so see it but you can just make out the damaged threads. The big problem here is the mount nut is welded to the frame. It’s built in. There is no easy replacement of that part.
What do I do about that? Again I hit the drawing board and did some more research. It turns out there is a tool for this problem. It’s a Tap and Die kit. Basically the tool recuts the threads. The Tap is the long component int he image which connects to a handle and allows the operator to screw in the new threads. This is the tool that I used to fix the mount hole. The Die is the round component and it is used with the different handle to cut the threads on the post of the bolt.
The process seems pretty easy until you realize that all the videos showing how the tap works are done on a work surface that is suitable for taking a video. Obviously inside of the wheel well is not an ideal surface. It was quite cramped and didn’t offer a lot of room to turn the handle. In fact, after only about a 1/2 inch of tapping it was impossible to use the 2nd handle as there was no space for it. Without a second handle it was very difficult to get the torque necessary to move the die. After all I’m cutting into hardened steel. Thanks to high school science I remembered what Archimedes discovered, the lever. I ended up using the handle of my bottle jack to extend my leverage point. That made the job way easier. Sadly that was not to be my final challenge.
The final challenge to this story happened with the tap inserted about 1/2 into the mount hole. The force needed to move the tap deeper was becoming so great that the tap handle began to slip. The tap handle is adjustable. Turning the handle left of right creates a bigger or smaller space for the various taps. If you’ve ever worked with an adjustable crescent wrench you probably already know what happened. It is very difficult to get a proper seat on a bolt or nut with an adjustable wrench. They are handy but they are also sloppy. Being sloppy means that eventually the corners of the bolt will slip as the force of using the tool pushes back against the adjusted setting of the tool. This is why fixed open end wrenches are always a better choice over an adjustable crescent wrench. The same principal applies to adjustable tap handles. As the force to move the tap increased the corners of the tap began to slip out. I needed something more decisive. That’s where a tap socket set comes into play.
The tap fits into the square hole on the socket which in turns fits onto my 1/2 inch rachet. The rachet is ideal here because of it’s range of motion. When the handle of the rachet reaches it max movement arc, it can be reset without having to remove the socket from the head of whatever your driving. In this case there was already limited movement in the wheel well. The rachet is designed to move freely in the opposite direction essentially resetting the ability to drive the tap deeper. The design of the rachet also allowed me to continue using my lever for a force multiplier.
I was eventually able to drive the tap all the way into the mounting hole. Each time I was able to drive a little deeper I would remove the tap and brush out the metal filings that were created as the tap cut its way into the mounting hole. I forgot to mention that the tap process requires lubrication. I used a dark cutting oil for the job. I reapplied the oil each time the tap exited the mounting hole. After driving the tap deep enough for the mounting bolt it was time to install the shock absorber with the actual bolt. I used brake cleaner and a tooth brush to clean up the oil inside the mount hole along with any remaining metal filings. I gave it about 15 minutes of dry time before applying the thread lock onto the bolt and going for broke.
A side note about bolts. That number displayed on the head of a bolt refers to it’s strength. While I don’t have the actual specifications of the OEM bolt I used Copilot AI to learn everything I needed to know about bolts. There are many grades of bolts and the 10 grade corresponds with 10.9 which have higher tensile and yield strength. More than the 8.8 grade which are used in structures. Auto builders use both 8.8 and 10.9 grade bolts in suspensions. Since I am taping an existing hole I was worried about the strength of the bolt but learned that general guidance is that you should have at lease 1x the bolt diameter worth of threads for maximum strength. This is because the width of the bolt then becomes the failure point as the bolt would resist shearing off up to the strength of the material contained in it’s diameter.
Conclusion
Copilot’s AI was a huge help to me on this project. It was like I had a master mechanic with me. The information about bolts was just one of many sessions I took with AI to increase my knowledge. It would be an understatement to say I learned a lot from the project. It almost kicked my butt but patience and perseverance and Copilot AI got me through it. Being remote didn’t help because each time I rose to the level of my tools and learned I needed something else, I couldn’t just run to the store and pick up the next tool. Instead I had to order the tools and let’s not forget the parts themselves. Each setback resulted in several lost days of productivity just waiting for packages to arrive.
After I put everything back together it was a huge satisfaction to be able to drive the car around without any front end noise and know that I did that. Yes, it took some time but it only cost me about $300 for the parts. Tools were probably another $100 but one can never have too many tools. That isn’t a cost, it’s an investment.