Saturday, July 7, 2007

Twelve Mile Road, the day after...

The day of Twelve Mile Road was a very exciting one in many respects. In addition to the "TMR" adventure, there was a bear, and a stand of virgin hemlocks, waterfalls, campfire cooking (interrupted by thunderstorm), intense rainbow, nice bike riding. All of that will come in future posts. Now we need to do a little follow up on the effects of the off road adventure on TMR.

The next day, I got up and took a nice shower and got going in the morning. First odd thing I notice while driving is that the shudder under braking had increased. I have mildly warped front brake rotors and that's the symptom. Brain goes into gear, what has changed that could cause that? A few miles later I hear a big bang like I ran over a stick and it hit the bottom of the van. I look in the rear view mirror to see if I can see a stick or a part that has fallen off the van. Nothing. Hmmm. More thinking. I implement a few mild test swerves. Hmmm. I decided to actually pull off and see if there is something serious wrong. Look at the right front wheel area and immediately notice the top of the shock absorber is missing. Yeah, that could cause a bang, and the increased shudder under braking. I grab one part that is still bouncing around in there and keep it for later. I grab and shake and kick the wheels to make sure nothing else is broken.

I drive on and confirm I have no shock absorbing on the right front wheel. I start taking turns to the left slower, since they load that wheel and I don't want to crash. I also started using a cruise speed of 55 instead of 60 because there was a vibration that started above 55. West Virginia has a lot of curves on its roads. Seriously. A LOT. They are labeled with signs advising how fast you can safely go around the curve. These signs are remarkably accurate and uniform. I developed a correction factor for how much you could safely add to the advisory speed. In the Vanagon, I came up with about +12mph, and this is assuming good sight lines. I hate coming around a curve to a surprise, and the van needs more room to deal with surprises, so I couldn't always add 12mph. I first discovered this phenomena back in the early 80's when I often drove across WV on US 50 to visit my GF Anne McQuary who was going to school in Ohio. That was in my '76 VW Scirocco, a much better handling car than the Vanagon. That car was +20mph, with less regard to sight lines.

Anyway, I stopped at a DIY car wash in Elkins and gave the underneath a good cleaning, and checked the suspension better to make sure there was no other damage. When I got home and started working on the shock absorber I was surprised to find it was completely intact and not even damaged. It appeared that the nut holding the top of it just came off. (Click the photo on the right to see the exploded view of the suspension if you want to follow along.) On further inspection, I found a few pieces missing. A metal spacer and a rubber bump stop. Both of these were in a place that they would have to slide off the top of the shaft of the shock, and it would have been hard for them to do that. The metal spacer is under compression when the missing nut was tightened. My theory is that during the bouncing and severe suspension travel on TMR, this spacer fell apart or got crushed. This took the tension off the nut and it just backed off and went bye-bye. Then the top of the shock fell down into the spring and sat there. I had spare parts from another van, swapped them in and now it's fine again.

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