20 Nov

The rear suspension rod-ends were upgraded and like the front, the job took all day. Before starting in and with the car on blocks, the tires were pulled back and forth, side-to-side to see how much play there was… there was a lot, maybe 5 mm* or so. Due to how the toe-control links tie into the uprights, any amount of play gets mechanically magnified out to the surface of the tires. This is the prime reason they were replaced, them loosening up so fast. I can’t blame anyone but myself for having used such poor quality parts in the first place. The first picture below shows the enormous difference; not only does the part on the left have specifications, its wider housing is about twice as strong, but also, the wider housing allows a wider Teflon bearing surface which has higher ratings and will also last longer. The difference in price is substantial, but given their task, I no longer trust the cheap ones. For background, the cheap ones were about $3, mid-range U.S.-made parts are about $11, and the good ones are around $26. The highest-quality parts were used selectively in the highest-loaded positions, and the mid-range parts used everywhere else.

I briefly considered selling the used joints to someone who would use them in non-critical applications, but thought better of it and into the trash they went. I don’t need that on my mind.

A few readers pointed out that since I twisted the steering arms, it shortened the steering rack to upright distance – that’s correct – and they wondered whether bumpsteer might now be an issue. I pointed out that bumpsteer, while a quantifiable and measurable value, is subjective to the driver. If the driver can’t tell the difference between “X” and “Y” amount of bumpsteer, it doesn’t matter. (I should have driven the car with the Miata tie-rod ends, but when I saw that there was some bumpsteer, I set out to eliminate it. In hindsight, even though there was some, it may have been fine as it was.)

The car was taken out for a test drive and I couldn’t detect any bumpsteer, but than again, it was Friday traffic and impossible to do any handling tests. During the drive I was heading downhill toward a traffic light… well, let me back up a bit and explain something. When driving, especially sports cars, we program ourselves to be hypersensitive to certain things. Just getting a glimpse of a black-and-white car is enough to make people back off the gas. There are other things as well, like smelling melting plastic, or coolant, or brakes that gets immediate attention. Such was the case slowing down toward the traffic light at the bottom of the hill, a definitely strong smell of really hot brakes. When I pulled the calipers off the rotors, a tiny bit of the brake pad broke off along the bottom edge; apparently the brake kit I used allows the brakes pads to hang slightly over the inside edge of the rotors. Smelling hot brakes made me worry that a piece might have gotten jammed somewhere and was causing the brakes to drag. Then I looked over and there was an old truck pulling a very overloaded trailer full of concrete debris – what a relief… for me, not so much for him!

In the last picture – it’s kind of hard to see – is a bunch of tiny white specs. Those all are dried-up bug goo, or more specifically, dried up locust goo from when I ran over all of them. That stuff is really hard to get off and just getting it wet doesn’t seem to do the trick. If anyone has some wonderful stuff they use, let me know.

*I’m making an effort to start using metric values. I’m already getting heat for not using metric values in the drawings, so I have to start somewhere!