I’m an enormous fan of maintaining previous automobiles inventory. Take a look at my fleet of hoopties, and also you’ll see that the one automobile with modifications is the one which I ruined with a carry package. However now I’m engaged on a 1966 Ford Mustang, and I merely can not in good conscience preserve it inventory. It’s simply too harmful.
If I—an individual who drove a $500 postal Jeep 3,500 miles throughout the nation after repairing its body with a $100 Harbor Freight welder—name one thing harmful, what I’m actually saying is it’s a deathtrap. And that’s what I’m saying about my brother’s 1966 Ford Mustang, which is wild, as a result of it’s no completely different than loads of different autos from its period.
The automotive is beautiful. The Candyapple Pink paint nonetheless pops, the physique doesn’t have a spot of rust, the powertrain has solely been pushed few miles (it hasn’t been registered since 1997), and the whole lot is totally bone-stock, simply as the horse automotive gods supposed.
The issue is, I can’t preserve the automobile in factory-original kind, and you may thank this factor proper right here:
It’s the brake grasp cylinder, and whereas the extra mechanically inclined amongst you might assume it’s apparent why the element above has me involved, I don’t assume the layperson does. So let’s evaluate that grasp cylinder to one from my 1991 Jeep Cherokee:
You’ll discover how the unique 1966 Mustang grasp cylinder has a single reservoir, or “bowl,” whereas the Jeep grasp cylinder is a dual-bowl unit.
The latter is way, a lot safer, however earlier than we get into why, let’s first discuss how a braking system works, specializing in the hydraulics. I describe all of it within the video beneath, however right here’s a brief description: Once you press your brake pedal, you push a piston (or pistons), which pushes liquid brake fluid by means of traces and hoses. The brake fluid transfers (and permits for the multiplication of) that pressure, out of your foot to the calipers or wheel cylinders, which press friction materials towards your automotive’s spinning discs or drums to cease the automobile.
The important thing high quality of the fluid is its incompressibility underneath quite a lot of circumstances. As an analogy, think about you must press a stiff button on a wall that could be a few toes out of attain. That can assist you, let’s say you’ve acquired two objects to select from: a floppy spring and an especially stiff spring. Which object would you select to push the button?
You’d use the stiff spring, in fact, as a result of its incompressibility permits you to switch extra pressure to the stiff button. This is probably not the best analogy, however the identical thought holds for a braking system. Once you press the pedal, you wish to guarantee that the piston your pedal is pushing within the grasp cylinder is urgent towards one thing incompressible (just like the stiff spring), in order that pressure will be transmitted to every wheel. That incompressible fluid is liquid brake fluid. (In the event you’re having a tough time imagining a liquid as “incompressible,” needless to say the liquid is constrained inside pipes, so it may well’t simply circulation wherever. You’re pushing a column of liquid on one finish, so it has to maneuver towards the opposite finish).
Gasoline within the braking system compromises efficiency as a result of gases are usually extremely compressible (just like the floppy spring). Gasoline can get right into a braking system numerous methods, together with by way of improper bleeding or by way of boiling due excessive braking temperatures or proximity to exhaust. Much more worrisome than gasoline within the fluid is a gap in a brake line or hose creating an open system that received’t permit for strain buildup.
The purpose is: On your brakes to work in any respect, you must have an incompressible fluid in utterly sealed traces. All it takes is compromised fluid or a leak in a line and that’s it: your brake system is toast! In case your parking brake is correctly adjusted (and let’s be actual, most aren’t), then you should use that to decelerate, however even then, parking brakes simply seize your rear wheels, and it’s the entrance wheels that provide the overwhelming majority of stopping pressure.
Lengthy story brief: You don’t want a brake line to go dangerous. However it occurs. That’s once you’re going to need a twin reservoir grasp cylinder.
Discover how the previous grasp cylinder is bone-dry, with loads of rust contained in the reservoir. That is the case as a result of, whereas changing some crusty gas traces, my brother by accident kinked the lengthy brake line going to the rear wheels, making a tiny pinhole leak.
As a result of the Mustang has a single bowl grasp cylinder, your complete braking system is all a part of a single related circuit. So, that single pinhole leak drained the entire fluid from the system, rendering the brakes completely ineffective.
It’s because of this that I —a person with “inventory is sacred” tattooed inside his decrease lip —had no selection however to implore my brother to purchase this twin reservoir grasp cylinder:
In my lifetime, I’ve had two autos lose brakes because of leaks. My 1991 Jeep Comanche and my 1992 Jeep Cherokee each had rust create eat by means of rear brake traces inflicting pinhole leaks. My landlord’s $1 Oldsmobile had the identical drawback. Typically instances, these leaks occur instantly and with out warning.
Fortunately, neither my landlord nor I ended up careening right into a automotive in entrance of us, as a result of my Jeeps and my landlord’s Olds have twin reservoir grasp cylinders. Because of this, though the rear braking circuit misplaced all of its fluid, the entrance circuit—which is totally sealed off from the rear—remained efficient.
If my brother had been driving when his brakes sprung a leak, he’d have misplaced all capacity to cease his 3,000 pound crimson pony, and he would nearly actually have crashed.
I’ll be putting in a twin reservoir unit on my brother’s Mustang quickly, as a result of the considered urgent my brake pedal and completely nothing taking place, all due to a tiny rock or some corrosion that I one way or the other missed, scares the crap out of me. And, for those who personal any one in every of dozens of pre-Seventies automobiles, it ought to scare the crap out of you, too.