I have the right tool for just about every job. You won't ever find any on the Snap-On truck; nor will they appear in any Craftsman catalog. The best part is, these tools are seldom exotic and hardly ever cost more than a quarter. In fact, I pluck most of them from the dusty crevices at garage sales and swap meets. While most would regard my various coffee cans filled with odd-sized fasteners, worn-out sockets, and broken-handled wrenches as junk, I prize them as treasures. I'd be a fool not to; they've fixed many a lost cause and saved me a ton of grief (not to mention money).
Most recently, my carefully selected palate of highly specialized tools extracted the inextricable. As you may recall, I mentioned in the May issue's electrolytic rust removal story that the process can break the bonds that lock together corroded metals. Well, there's good reason I said can rather than always; the process couldn't break loose the pistons in that master cylinder. Why? The pistons were aluminum, and the galvanic reaction that corroded them within their iron bores over the decades effectively locked them solidly in place.
Ordinarily, heat and a few well-placed hammer blows through a drift would free such a booger, but the blind hole the piston lived in precluded that option. I also could've delivered hydraulic pressure generated by a grease gun through the outlet, but that required the right inverted flare fitting (which I didn't have), some fabrication (which I didn't want to do), and the integrity of a 40-year-old rubber piston ring (which I didn't want to count on). Even if everything went my way, I still don't know how I would've kept the pressure from escaping the fluid inlet in the reservoir once the piston uncovered it.
So I brought out the gimps. Drawing upon pearls imparted by a crusty old machinist friend, I decided to make the piston itself part of the extraction tool. By tapping the piston, I used a bolt and the mechanical advantage of their threads to generate enough force to extract the piston.
I could've used this force two ways: against the interior of the cylinder's closed end or against the perimeter of the cylinder's open end. I chose the latter, as the first option required threaded rod (which, curiously enough, I don't have) and a through hole, which would've totally destroyed the piston. My choice required an oversize socket, as you'll see, but that's easy; I can't resist random giant sockets and rescue just about every one I encounter.
This trick has more uses than merely extracting pistons from master cylinders, by the way. In fact, its potential is unlimited. Simply slip the fastener through an oversize socket on one side of a wrist pin and into a nut on the other side of the same wrist pin and you can safely remove junk pistons from good connecting rods. The same goes for kingpin bushings; I've extracted and installed many this way with great results. Leaf-spring bushings are a piece of cake, and one of my old shop manuals even shows how to replace lower control-arm bushings this way.
Master the art of improvisation with humble tools and you'll surprise yourself with your ingenuity and astound your buddies with your abilities. Not only does it feel good, it sure beats selling your soul to the local tool dealer.