The “Ah Hah!” moment – NASA AI Javelin update!

The Trackmasters event was a mixed bag. I didn’t go any faster and I cut a tire which meant I didn’t get to run the last two session. The tire got cut because I didn’t run the ½” front wheel spacers I usually use. However, cutting the tire has lead to a HUGE breakthrough because it lead to the discovery of what’s been causing my brake shimmy!!!

Ever since I lowered the car I’ve been having problems with a bad shimmy/shake under braking. Early in 2015 I was just having weird issues with the car. Shimmy under braking and some weird side to side motion under acceleration. When we discovered the 3rd link ripping out I thought, ah, that’s it! But, with the 3rd link mount fixed and re-inforced I was still getting the shimmy. I didn’t realize it but over time I had trained myself to use the brakes less and less. So I had sort of fooled myself into think the shimmy was still there but that it wasn’t that bad…

The day after the Trackmasters event I got the car jacked up and pulled the front wheels. My plan was to remove the 3 bolts that hold the remote oil filter and relocate the filter slightly to move the bolts farther from the tire. However, while looking in the wheel well with the wheel off I suddenly saw what had happened… The first was the real breakthrough. I noticed the undercoating was completely worn away from the bottom of the fender trough! THAT’S what the shimmy was. Under braking the top of the tire was hitting the bottom of the fender trough. That’s what was causing the violent shaking when I really used the brakes. If I used the brakes lightly, the front didn’t dive as much and the tires didn’t hit. I check the drivers side and it had the same wear so I knew it was happening to both sides. Seroius “ah hah” moment… What had been cutting the tire was also obvious. The upper spring perch had wear marks from the tire and I realized that, without the spacers, when I was turning left the passenger side tire was contacting the edge of the perch and getting cut. Not sure why it wasn’t symetrical but it did not cut the drivers side tire…

Anyway, I was jumping with joy because now I knew what the problem was! ok, I guess I Don’t know 100% till I run the car again but I’m willing to bet big money that this is the problem that’s been plaguing me all year. No worries, nothing a little quality time with the grinder and a cut off disc can’t solve!

It was actually pretty hard, dirty work but I got all the offending metal cut away and I plated the notch I made in the fender trough. I’m a little concerned that maybe I should have made the notch even longer but at least I know what the issue is. If I’m still hitting next time I run I’ll know I just have to keep cutting till there’s enough clearance Clarance!

Unfortunately I’ve run out of time and won’t be able to make the Sept. race. So now I’m shooting for October.

1974 Javelin-road race, American Iron, Body and Paint, Suspension, Wheels and Tires

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