Replacing Brake Rotors and Pads

Apr 26, 2013 View Comments by

Replacing Brake Rotors and PadsIn this article, we’ll focus on replacing the front disc rotor or rotors and installing new brake pads. The project bike is a 2011 BMW F650GS with a single solid (non-floating) rotor and a two-piston caliper. However, the procedure will be about the same for most modern motorbikes equipped with disc brakes.

The replacement disc is a Galfer floating disc wave rotor. The advantage of this design is that the floating disc makes better, more consistent contact with the brake pads, and the wave pattern tends to be self cleaning (keeping the brake pucks free of dust and dirt), and runs cooler—all of which provides much better stopping power and feel. This is a fairly easy job and should not require any special tools. The procedure is:

Replacing Brake Rotors and Pads1. On most motorbikes it is advisable to remove the disc calipers and disconnect the anti-lock brake sensor prior to removing the wheel (see your bike’s shop or owner’s manual for the recommended procedure).

2. Remove the front wheel and place it on a flat surface with the rotor up. If you have two rotors just pick a side, but be careful not to damage the rotor on the bottom. I suggest you use wood blocks or something under the tire rim to lift the wheel off the work surface.

 

 

Replacing Brake Rotors and Pads3. Remove the bolts that attach the rotor to the wheel. I always recommend loosening the bolts in a cross pattern to keep from placing any torque forces on the rotor.

4. On the F650GS, the small ring with the slots is the anti-lock brake sensor ring, which you will reuse, along with the screws.

 

 

 

Replacing Brake Rotors and Pads5. Put the new wave rotor on the wheel and align the screw holes, it should be an exact match.

 

 

 

 

 

Replacing Brake Rotors and Pads6. Replace the anti-lock ring; again, it should be an exact match.

 

 

 

 

 

 

Replacing Brake Rotors and Pads7. Check and clean the threads on the screws. Apply a small amount of blue Loctite to the screw threads. You don’t need much, as it will spread out as you tighten the screws. Hand tighten the screws that hold the anti-lock ring and rotor.

8. Tighten the screws to the specified torque from your owner’s manual. If you don’t have a proper torque wrench, I highly recommend you invest in one, but you can also tighten the screws until snug and then 3/4 of a turn more. Remember to use a star or crosshatch pattern when you torque the screws, so as not to warp or twist the rotor assembly.

9. Replace the brake pads with the recommended Galfer pads (I use the sintered G1370HH pad, but the G1054 organic pad works very well for most street applications). It is very important that you replace the pads when you replace the rotor. Don’t cheap out and try to reuse the old pads, even if they look to be in good shape. Old pads can cause uneven wear, glazing, damage to the new rotor, and will void the Galfer warranty.

10. If you have a two-rotor system, which almost all BMWs do, turn the wheel over—keeping the disc rotor off the work table—and repeat.

11. Offset the wave pattern. You do not want the low points and the high points (troughs and peaks) of the wave pattern to align. Make sure that the right wave trough is opposite the left wave peak or the braking will feel uneven and grabby.

As you can see, replacing the rotor is a very simple job and well within the skill level of anyone who is comfortable doing a little wrenching. Replacing the brake pads is also a very good do-it-yourself project, whether you replace the rotors or not, although it does require a little more skill. The details of the swap will vary between calipers, makes and models, however, it isn’t complicated. I won’t go into the exact procedure as it will vary between motorcycles, but there are a few things that you should keep in mind when replacing your pads. Since you have already removed the caliper and the old pads, now is a very good time to clean and check the caliper. When installing new brake pads, Galfer recommends that you do the following:

1. Clean around the pistons of the caliper according to your service manual (a soft toothbrush helps). This will allow the pistons to slide easier and give you better release for the brake pads.

2. Clean the caliper pad slide pins if equipped. This will help the pads retract when the lever is released.  A dry, clean Scotchbrite or Brillo Pad works well for this.

3. New brake pads should be bedded into clean rotors. Start with slow stops ranging from 10-15 mph and increasing in blocks of 10 mph until about 40-50 mph. Repeat this step two to three times at each speed and resume casual riding. Bedding in brake pads helps prevent glazing, aids in mating the pads to the rotor’s surface, and promotes longer rotor and pad life.

4. With wave rotors, Galfer recommends chamfering the leading edge of the new pad to help it set better and avoid any initial grabbing. Remember, the leading edge is at the bottom of the caliper—the wheel rolls forward.

Replacing Brake Rotors and Pads5. Chamfering means to put a 45-degree angle on the edge of the brake pad. Hold the pad at an angle and gently rub on some medium sand paper (see illustrations at left).

6. When remounting the calipers it is common to have to push the new pads apart to fit them over the rotor. Be careful not to push them too far in as this could cause the brake fluid reservoir to overflow, which is hard on paint and makes a frightful mess. Also, new pads are thicker so check the fluid level after assembly.

7. You will want to make sure the wheel and caliper(s) are aligned properly. To do this mount the caliper(s) and wheel with brake bolts, axel, and pinch bolts finger tight. Pump the brakes several times until they feel firm. While holding pressure on the front brake lever (it helps to have a friend hold the brake lever) tighten the caliper mounting bolts until snug then do the same with the axel and pinch bolts and then, using a torque wrench, check that all bolts are to the specified torques (from your owner’s manual). Note that some manufacturers recommend using Loctite on the caliper-mounting bolt. I like to use a small amount of blue Loctite, just remember to clean the screws with a metal brush before reinstalling them. Old Loctite can “grab” the bolts, giving you a false torque reading by indicating that the bolts are tighter than they really are.

Replacing Brake Rotors and PadsAll of this is fairly easy and makes a huge difference in how well even stock brakes work. Better feel and shorter stopping distances are important safety factors and the added confidence and control you get can really improve your riding.

For more information, go to  the Galfer Brakes web site (www.galferusa.com) and watch their excellent videos.

 

 

Text and photography by Robert Lamishaw

 

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