I am planning to deliver Gail and Daniel’s Miata to them in Cambridge in early April. Daniel first said he would come to Washington to pick it up, but 
we agreed his opportunity cost is much higher than mine. We decided that I would drive it for an already-planned visit.
After the new timing belt and water pump, I installed new radiator hoses, belts, and a valve cover gasket. All of these parts need to be removed for a timing belt service. On disassembly, the alternator belt was frayed, and it and the power steering belt were cracked. The lower heater hose had a few soft spots, and there was a small oil leak on the corner of the valve cover. The heater hoses seemed to be in good shape, and did not need to be touched for the timing belt work. I left these for another day.
Because the Miata would be heading North, I made sure that the coolant contained enough antifreeze for their cold climate.
The engine fired up on the second crank, and much to my surprise I found no oil or coolant leaks. I am assuming that this is a testament to 
On the drive home in the Miata, I noticed a low hum from the front of the car. I was concerned that a wheel bearing might have failed. To test this suspicion, I jacked up the car and tugged at wheels looking for excessive wiggling. Finding none, I took the next step I attached “chassis ears,” small microphones that connect to headphones. I purchased this tool to diagnose a similar noise in my Subaru years ago. I went for a test drive around the pond and, sure enough, heard the distinctive low grumble of a bearing gone bad.
Miata wheel bearings are easy to repair. In the
picture above, I have removed the brake caliper (hanging on spring in the upper right and the brake rotor (in the lower left corner). This exposed the hub in the center of the picture. The bearings are sealed into the hub, and one simply removes the entire hub and bearing assembly. The new hub slides onto the axle spindle, shown on the right. I have already applied grease to the spindle, although it is not clear to me why this is needed since the bearings are pre lubricated and sealed.
It turns out that there are many price levels for
replacement hubs. On the internet, no name parts are available for around $25, and parts stores such as NAPA and Auto Zone sell them starting at around $70. These groups come with one year guarantees, and I assume they are roughly the same quality. The Mazda dealer sells hubs for $280; I decided to look for name brand parts, hoping that they would be equivalent to the dealer stock in quality. The internet indicates that this is true, and several reviewers said that dealers were supplying Timken hubs as Mazda parts. I opted for a pair of Timken assemblies from Rock Auto.
While I had the wheels off, I decided to tackle a broken fastener on the inside left fender. From the factory, a bolt held the plastic lower engine c
over and the inner fender to the frame. But the bolt was snapped off, leaving these parts a bit loose. The easiest solution was to drill a new hole, tap new threads into it, and then use a new bolt to hold the parts together. Removing the broken bolt would have been possible but not worth the extra effort since a precision fit was not necessary. A new bolt hole next to the old one would work well enough.
To the right is a tap tool inserted in the new hole. Taps are made of hard steel and have teeth that cut new threads when turned clockwise. Below is the new bolt holding everything together.
Back on the ground, the Miata runs well and
is ready for delivery. The brakes are in excellent condition, the tires are near new, and routine services will not be needed for a year. Working on a modern Mazda was fun and reminded me of the WRX engine in the 818 kit car. I am glad I was able to help Gail and Daniel.
Sunbeam 