A Balanced Approach – on to the brakes

As I mentioned earlier it is great to go fast, but such a relief to be able to stop or slow down when you really need to.

Hydraulic brakes have made some big improvements over the years.  The transition from drum brakes to disc brakes have made huge improvement.  No more soaked drums full of rain water.  It will be a long time before I miss the joys of doing a drum brake job with all the springs and cables to deal with.  They were famous for having leaking wheel cylinders that would coat the brake shoes with fluid while staying hidden behind the drums.  Adjusting drum brakes was more of an art than a science.

ABS is one of those advances in automotive technology that few really appreciate.  Most folks see ABS as that computer controlled miracle that allows them to slam on the brakes in a panic and allow the system to modulate the pressure so they can come to a controlled stop.  Well, sort of.  What ABS really facilitates is your ability to still maneuver while bringing your car to a halt.  Prior to ABS there were the techniques of pumping your brakes and threshold braking as your options. 

Your braking system relies on the fluid not being compress-able and its ability to deal with the heat generated at the rotors.  The fluid is also hygroscopic which means that it will pull moisture right out of the air.  So over time water will accumulate and this will drive down the boiling point of the fluid (bad) as well as corrode the brake components from the inside (also bad).  That is why we should change and flush our brake fluid at least once a year.

Every car has a different method of bleeding the brakes, but most of the time you start with the farthest corner (right rear) and work your way inward.  Acura starts at the left front and works clockwise, while Mitsubishi starts with the right rear, then the left front, left rear, and right front.  Some cars do this with the engine on while others do not.  Check the manual before you bleed the brakes on your car.

There are some great systems for bleeding brakes out there from pressure bleeders that provide fluid under pressure from the master cylinder reservoir to vacuum bleeders that pull from the bleeders.  When I was a the practice for the Indy 500 and watched the mechanics set up the race car they did it the old fashioned way of using the brake pedal and opening each of the caliper’s bleed screws in turn.  If you want you can pick up a set of speed bleeders (http://www.speedbleeder.com/) for your car and get some clear hose from an aquarium shop and save a small plastic milk carton.  That way you can go from wheel to wheel and not leave a mess on your garage floor.  Stop Tech has a general brake bleeding white paper that goes into detail (http://www.stoptech.com/tech_info/wp_howto_bleedbrakes.shtml).

When you feel its time to replace or upgrade your brake system with some new pads and rotors you will need to bed in the new pads.  Stop Tech has some excellent tutorials on bedding in pads (http://www.stoptech.com/tech_info/wp_bedincontents.shtml).  What this does is get the pads “friendly” with the rotors.  It is a gentle way of getting the two different surfaces working together without glazing either the pads or the rotors.

Speaking of pads and rotors, there are a lot of choices open to you that will either enhance the capabilities of your car’s braking system – or not. 

There are a lot of rotor choices out there.  For the street you can get rotors that are higher quality castings than the stock and offer you the “bling” of drilled holes and slots.  The drilled rotors are patterned after rotors that are used in racing and on some high end sports cars.  When used under racing conditions they have been known to crack at the holes, but on the street they can offer additional cooling as well as the good looks.  Slotted rotors clean off the glazing that can build up on pads as well as allow gasses from heated pads an escape path.

Many companies offer brake upgrades that offer larger diameter rotors and far more sophisticated calipers.  Baer, Brembo, Wilwood, Stop Tech, Stainless Steel Brakes, to name a few.  Many of these kind of upgrades will require larger wheels for clearance.  Larger rotors mean more mass to deal with the heat generated from braking, along with a larger lever arm as the caliper is moved out farther from the center of the rotor.  The aftermarket calipers are usually designed with more pistons and ones that apply pressure on both sides of the rotor.  Stock calipers, for cost reasons, are usually a single piston design that must slide in a frame so that the clamping action is maintained from both sides of the rotors.  High end sports cars such as Porsche, Corvette, Evolution, WRX, come with multiple piston calipers.  These will have bleed screws on the inside and outside of each caliper. 

Wheel diameter is not the only consideration with these kinds of upgarades.  You also want to ensure that replacement pads are not difficult to get and are offered in compound choices that will fit your drving needs be they street or track.

Some companies, like Performance Friction, makes full floating brake rotors available for some makes of cars.  These rotors allow the area clamped by the calipers to float independent of the rotor’s hat.  This is especially effective on the road racing track.

We can write about brakes for a lot longer, but I’m sure you’d like to learn about some other aspects, like the suspension.  More later.

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This entry was posted in Cars, Modifying Cars, Road Racing, Sports Cars, Suspensions. Bookmark the permalink.

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