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May 9, 2017
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Replace the pads, bleed the brakes & other things you need to know.

Speeds that go up must eventually come down—sometimes in a hurry

Modern quads have three different types of brakes. Big machines like the Kawasaki Brute Force 750 have sealed, multidisc brakes that operate much like a wet clutch. For the most part, these are indestructible, even if they are heavy, expensive and complicated. At the other end of the ATV universe we have drum brakes. These are simple and inexpensive, and are only used on lightweight, entry-level machines. The vast majority of modern ATVs have hydraulic disc brakes, which offer excellent power, light weight and good reliability. But they aren’t indestructible. We talked to a number of brake experts, including Aaron Hodak of Galfer Brakes, to get these basic brake tips.
Back in the days of Blasters and Banshees, you had nothing between you and that big tree but your brakes. But in the era of four-strokes, things have changed. Your motor shares the burden of stopping, so despite having heavier machines, brakes can last longer. Even if you have a CV transmission, most offer some sort of simulated engine braking. Small quads with centrifugal clutches have an interesting trait. They have engine braking down to very low rpm, then suddenly freewheel. This isn’t a factor unless you are idling and then start rolling downhill. You have to gas it briefly to engage the motor before compression can slow you down. The point of all this is to know your quad so that you can make your brakes last longer.

Heat is the enemy. Brake fluid is made to withstand incredible temperature, but eventually, you’ll over do it. That’s when you need to replace your old fluid with new stuff. Brake fluid absorbs moisture from the atmosphere, and it can break down with repeated cycles of hot and cold. Change your fluid using DOT 4 fluid from a bottle that’s freshly opened. A previously opened bottle will be contaminated with moisture after about six months and will be no better than the stuff in your master cylinder. That’s bad because water acts very different from brake fluid when it’s heated. That’s why we don’t use water in our brakes.

If you still have a few millimeters of brake pad material before you go metal to metal, don’t get cocky. In many cases, modern brake systems don’t have enough fluid capacity to push the pistons out more than 5mm or so. If you have 8mm of brake pad material, that last 3mm is just for looks. The good news is that brakes often stop working before going metal on metal and ruining your discs.

The more material on the brake pad, the more insulation you have between the disc and the caliper, so heat fade is less of an issue. Many companies like Galfer sell different types of compounds. Semi-metallic are good general-use pads. Sintered pads are generally more aggressive and can withstand higher heat, but will wear a disc more rapidly. Kevlar or Organic pads are softer, but will wear out sooner. When you switch pads, you’ll get the best performance with a new disc. At the very least, you should clean your disc to remove the old pad material.

Worn out discs are often to blame for weak brakes. Does your disc have little grooves and scores? That reduces your braking surface dramatically. You can’t take your disc to an automotive machine shop for resurfacing because you don’t have enough material to lose. But you can do some resurfacing of your own with a sanding block and 600-grit sandpaper.

The most neglected part of your brake system is the hose. Your quad came with an inexpensive rubber hose that wears out in about a year. When that happens, much of the force that you apply with your hand or foot is expanding the line like a balloon. Steel braided lines will give an old quad a very cost-effective upgrade in performance.

Riders underestimate the braking power that may be lost from old flexi rubber hoses. Steel braided lines can give new life to old binders.

It’s hard to beat the old-fashioned pump-crack-and-bleed technique as long as you keep several things in mind. Start with the wheel that’s farthest from the master cylinder. Don’t introduce air into the system at the bleed valve. Remember, the bleed nipple on your caliper uses a tapered pipe thread. Air can easily go around the threads; it doesn’t have to go through the front door. Make sure the nipple is fully seated before you release pressure on the brake or you will suck more air into the brake, regardless of any hoses or tools you have connected to your bleed nipple.

Gary Jones has his own way of bleeding brakes, as do most good mechanics. Just remember that brakes want to rid themselves of air, and that bubbles travel upwards, so you’ll be fine. The bleed nipple on most brake calipers uses a pipe thread. This means the fitting is tapered and that air may go around the threads, no matter how well the hose is fastened in place.

Are your brakes squealing? More often than not, this is because you have contamination on your rotor. You might have a little organic pad material that doesn’t like your new semi-metallic pads or vice versa. Clean your disc carefully and wet sand it. You’ll see the old pad material coming off.

Different kinds of mud require different kinds of rotors. The original Galfer Wave rotor was designed to clean sticky mud from your pads, and it does that well. In abrasive mud, many riders like solid rotors with no holes whatsoever. This doesn’t really help performance, but you can get longer pad life.

Galfer originated the Wave rotor in order to help clean the pads of mud and debris. A side benefit is that this design is lighter.

More often than not, bad brake habits are the cause of brake failure. If you ride your brakes, take steps to break yourself of the habit. Adjust your brake lever height lower or use a stiffer return spring. Or, just think before you stomp.

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