Front Sway Bar Adjustments & Brakes

I really am trying to get you caught up with the developments of the car because I would like to blog about other things besides the Miata. But I don’t feel right about doing it when I’m three weeks behind with the updates. And so with this post we should be up to date. After the 9/23 SJR autocross where I found the front sway bar was hitting the upper control arm I got to work on a solution. The CSP driver I talked to suggested that I purchase some female rod ends from McMaster-Carr to make shortened end links. I wanted to salvage as much of the Mazdaspeed links as I could. They were not as expensive as some other end links I saw while looking around for solutions, but that is no reason to throw them away. I paid for them, I wanted to more than three events out of them.

So I came up with a plan to cut the middle part of the ends link. This is a piece of aluminum hex bar stock with a threaded hole down the middle. I took one end link apart to measure. It looked like shortening the middle part by 3/4 inch would do the trick. I found out that one of the rod ends was a left hand thread, opposite of normal. This meant I would have to cut the peace on both ends. And I also figured out that I would have to shorten the threaded shank of the rod ends themselves. I already had them threaded in about as far as they would go and much more and they would hit each other inside the middle piece. I took one of the left hand ones and test cut about 3/8 inch from it with my Dremel. It drained the Dremel battery down in the process but it worked.

I was skeptical about cutting the middle pieces on my own. A jam nut locks against the end of the middle piece, where I would be cutting. So if I cut badly (I probably would on a part this wide) There wouldn’t be a good seat to tighten the jam nut against. I talked to someone in work about using a band saw in our R&D lab to cut them. Apparently the band saw blade is quite dull and he suggested cutting them on our pipe cutting bench. I would have to wait almost two weeks till my next Friday off or borrow the key and go in on a Saturday. As I thought about it I got worried that the middle piece would not fit into the pipe cutting bench being smaller than most pipe and not very long. So I fell back to plan B and ordered the female rod ends from McMaster Carr. They were only a few dollars each.

In the mean time, the next weekend I had to fix the other issue with the sway bar which was binding in the bushings. I just used the washers under the bracket method. They were pretty easy to install. I worked one side at a time so I did not have to take the bar all the way down. Each bracket has to bolts holding it up. I loosened them both but only removed one at a time. I found that I needed not one, but TWO washers to space the brackets away from the frame enough to prevent binding. The bolts holding the bracket in are M8 but 5/16″ washers will work fine. The ones I bought from Autozone were marked for both. Once all the washers were in and everything tightened back down I could rotate the bar by hand. Sweet.

I also attacked the brakes. The car had developed an annoying squeak that sounded like brakes. If you recall when doing the suspension I discovered that one side of the rear pads were almost down to the backing plates. I suspected the noise was that side. I also had a vibration in the front from that snafu that happened with the rust under the rotor. The Miata, has a known issue in that they tend to lock up the front brakes. The balance is biased too much towards the front. The common remedy is to put an aggressive compound in the rear and a lower end pad in the front. Even though I don’t know what brake pads are on the front I don’t think they are anything special. So I left them alone.

For the rear the most aggressive street pad you can buy is the Hawk HP+. I had them on the front of my Prelude and hated them. They are very noisy. Now most of us “racers” are used to trading off noise for increased performance and bite. But the HP+ was just too much of a trade-off. They made noise all the time, especially when warm, like when you are in traffic! On the Prelude they were so aggressive I was constantly activating the ABS. The Miata doesn’t have ABS. And they dusted like crazy. So I chose the next step down, the Hawk HPS. They are a reasonable compromise. They have good bite, but good modulation. And not not squeal, grind or dust like the HP+.

I shopped around for the font rotors online. Autozone rotors are good enough for even the abuses of road racing so they are good enough for autocrossing. And they are normally pretty cheap. Not so for the Miata. They were somewhere around $50 each. The best price was $25 each for Brembo “blanks” through the Tire Rack. Brembo is a high end brand so that was a no-brainer. The brake stuff went without any problems (FOR ONCE!). I had to wait till Thursday for the female rod ends from McMaster. I put them in that night int he dark so I could take the car for a test drive Friday. The next autocross was on Saturday. I had to screw one of the rod end pairs together a lot. The other was at the minimum number of turns I felt comfortable with. Something seemed off but I had to just get them on and drive. Next post I’ll tell you how I did and I make some more adjustments to the car.