Gears & Such: March 2011

I have been preparing an involved post about vacuum cleaners and fluid dynamics. One broke, so I fixed the other, and then we got seriously curious about which one was really better... and then someone used a pressure guage and now I'm all wrapped up in Poiseuille equation (the textbook I have dates from the 1950's, references the manhattan project numerous times, and uses units that are hard for a modern mind to appreciate).

It was about this time that Google informed me that the browser on the mac was no longer supported for one of their products. The Mac, a Dual 1 Ghz G4, is almost 10 years old. It's underlaying architecture (USB 1, ATA-66, AGP 4x, PC-133 ram, it even has a SCSI card) is closer to 11 or 12. It keeps failing to fail. However, it is getting increasingly hard to keep up to date software installed.

Camino appears to be the lastest casualty. The mozilla project no longer supports embedding the gecko engine in other browsers. The number of technologies modern browsers are now trying to leverage in order to make web apps feel like real applications are many, WebGl and GPU compositing, HTML5, H.264 video decoding, fast javascript interpetation. It's hard to make all that modular.

Of course, the underlaying issue of if/when/how to replace the machine go un-answered. For doing actual work, it still is fine. The needs of analyzing experimental field data just haven't kept up with the shocking amount of computational powere available to the average dude.

Although, I do have to admit a certain desire to use Adobe Lightroom to manage and edit photos, something the current machine just can't muster...

Life goes on.

Back in the fall, I picked up a 1990 Volvo 740 wagon from a co-worker who was leaving for greener pastures. I thought it had 236,200 miles on it. It turns out that Europeans expect their cars to last longer than 100,000 miles, so it really had 362,000 miles. And that was with numerous speedometer failures over the years.

While trying to convince the taillights to function (after I purchased it), I took apart the dash. I found that the clutch pedal was nearly completely plastic, and had a deep long wear groove in it where the master cyclinder clevis linked to it. There was 1/4" of plastic left. I figured it was fine. Plenty of wear left.

It turns out, that 1/4" of plastic was structural, a small fact that would lead to nearly unterminable lamentation.

A few weeks ago, following an amazingly fun afternoon hike, The Dog, The Girly, the Volvo, and I were cruising the back roads of Great Falls (playground of the Washington Elite). We hit a steep hill and I stuffed in the clutch pedal to make a graceful, unpowered decent. Except that's not what happened. Instead, the clutch made a crunchy popping clunk sound, and then slammed against the firewall. I pulled my foot back to try again (as if it was a simple mistake and another go would clear things up). The clutch dangled uselessly against my boot.

Well, damn.

So, it was a really a less graceful powered decent, after which I took the car out of gear, stood on the brakes, and pulled over into the weeds.

The Volvo is a wrench whore. It is made to come apart easily, it is missing many troubling screws and bolts that it came with, and the nylon grippers that hold the interior panels on are all warn, so the process of getting to the root of problems is usually a trivial task of pulling things out. It begs for you to fix something every time you drive it. I used the back of my key as a driver and pulled out the first of the three dash panels (the rest being Torx, which I didn't have). Standing on my head, I could see the broken clutch linkage.

We briefly considered the virtues of taxis and tow trucks. The Dog, of course, complicated the issue, as did my lack of desire to loose a few hundred dollars on the experience.

I lay on my head with The Girly's super-bright LED flashlight (Sidebar: are these things amazing or what? 1 AAA and it's a gajillion times brighter than those maglights we had in the 80's and 90's). The situation reminded me of all those team building challenge questions we got in Odessy of the Mind and other extra-curricular activities for science-geek types. Here we were, stranded in the wilds of Northern Virginia, a good 20 minute walk to the nearest McDonalds, could we free ourselves? Would we have to dial 0 and pay for directory assitance? Would the unending string of Lobbysts driving by in their Nazi Sleds and Caddys stop to help a couple of muddy psuedo-hippies in thier stinking jallopy? My mind raced with questions.

I wondered: what do I have in the car that I could use to patch this up for a few good thrusts (of the clutch)?

In my backpack, I have a bag that my friend Packrat would describe as "The bag of everything you'll never need." Usually, it is, in fact, a useless 3 lb lump in the bottom of my pack. However, that 3 lb lump had a handful of zip ties, 50 ft of nylon cord, and a stitching awl with beeswax twine. Things that could be useful.

I went for the zipties first. They saved me when the ChevOldsmoBuiac dropped the muffler in March of 2008. I looped them over the top of the clutch and threaded them through the master cylinder clevis. Unfortunately, the the clutch master cylinder takes about 50 lbs to actuate, which was far more tension than the pathetic zipties I had were willing to manage. Especially considering the force amplification by stretching the zip tie perpendicularly to it's direction of travel. The beefy zip ties, of course, were too short. The small ones had a nice dissatisfying pop when the broke. The clutch pedal was made out of cheap plastic, but it was still a force amplifier. Nix that idea.

The blood was really starting to rush to my head now. The squirrels were growing restless as the pressure built. The mudd boots sticking awkwardly out of the drivers door must have looked odd. I hoped that no one would hit me. The airbag would ensure my pelvis would go undamaged by the impact, making for a strange story to tell Cerbrus as I waited for my turn to cross Styx. "And that's why my head is concave..."

I realized that if I took the cotter pin out of the the clevis, it would straddle the remains of the linkage on the clutch pedal. Then I would just have to provide stabilization to prevent it from wiggling free, I didn't have to find a new way to secure 50 lbs to the clutch. I elected to use the nylon cord, as a single strand was theoretically up to the absolute force, and then I could use what I could remember about knots and lashings to secure it to the pedal. I cut a 10 foot piece, put a clove hitch on the fat part of the pedal, and started throwing loops over the clutch pedal and on the bottom side of the master cylinder link. I put a couple of hitches around the clutch pedal at various points, because it needed to be very tight... the nature of the clutch swing would tend to loosen it as the clutch was depressed... I really didn't want it coming free before we got home.

By now, there was more blood in my head than in my feet, so I was woozy and needed to hold on to something when I pulled my self up, because my legs weren't working so hot. Normaly, I need a lot of alcohol to feel like that, but auto repair can do that to you too. I gingerly stepped on the clutch. In. I let go. Out. It felt ok. In a nervous, "I just hacked this together with a bit of nylon cord and now will go brave DC traffic" kind of ok. I looked at The Girly. She Looked at me. Our eyes locked.

In. Out. In. Out. In. Out. In. Out. In. Out (went the clutch).

Satisified that it would probably not break once I got the car going, I turned the ignition on, and started the engine.

In.

Out.

And off we went on a very nervous drive home.

Once, home, I drank a cuppa joe and then made a trip to the hardware store in the other car. I gathered washers and epoxy. I had a plan. That plan involved a little dremmel grinding and a lot of careful epoxying. The thought was to replace the original linkage with grade 8 steel washers. The result was beautiful. I was so excited.

I installed it in the car with great satisfaction. I carefully torqued down all the bolts and neatly greased up the new parts. I pressed gingerly on the clutch pedal with my fingers, and old lady leverage smiled and screwed over all my hard work. With crunchy thump, the I was showered with epoxy and greasey washers.

Lovely.

I determined that I needed to brace the clevis against something more substancial. Most pedals actuate from the back, not the side. In that senario, it would be trivial. So, the next day, I went to the hardware store and got a really long bolt, some washers, a big hose clamp, and epoxy putty.

From this, i created an ugly monstrocity. There's a lot going on there. The pipe clamp and the epoxy brace the bolt against the clutch. The washers on the left and right stabilize it against the clutch pedal body. I used anti-sieze compound because I don't have any real grease. It's all slimy anyway, right?

That's what's in there now.

I tried very hard to find a replacement clutch pedal. None of the junkyards within 100 miles had one. The volvo dealer does, but it's $70.00+. For a piece of plastic that breaks!

I am frustrated that an otherwise tank-like vehicle has a plastic pedal. The brake pedal is obvously made of some metalic substance. If I jam on the brake, I am not worried that it will randomly fail. Why shouldn't the clutch be the same way? Isn't it worth putting a solid part into a nominally solid car? Could a small iron sleave been put into the clutch pedal to prevent wear? Was someone home? Sheesh.

Volvo Design Fail.