The Front Brake's Performance is Critical
If you're unsure about replacing the front brake pads or doing other brake work on a dirt bike, be assured that doing so is really not all that difficult, although should you be interested in more of the technicalities of a specific dirt bike's braking system than what this article covers, be sure to refer to a Factory Service Manual specific to the motorcycle being serviced.
Keeping the dirt bike's brake pads, brake rotors, brake pins and all the other parts that make up your braking system in check is a really good idea and can benefit you in more ways than you may initially realize and this is especially true if you're a competitive minded rider as being proficient in knowing what to look for on the brakes, as well as being able to change the dirt bike's front brake pads can increase the braking performance and keep money in an enthusiasts or starving privateer's pocket while maintaining the front braking system.
Keeping the front braking system in it's best possible condition can
undoubtedly aid in out braking a competitor into the first turn (really any turn on a track) and this is true whether it be a motocross track, or after holding it wide open across a straightaway before diving back into the woods on an off-road course with someone right beside you. Additionally, having good front brakes is equally important if you're hitting the ramps since available stopping distances are usually pretty tight during competitions so the following tips may prove very enlightening to some although if your braking performance is suffering due to a soft feeling lever, you should check out our article on bleeding the front brake as fresh fluid can dramatically increase the front brake's stopping and staying power.
What to Look for When Inspecting the Front Brakes
Often times, a quick visual inspection of the front braking system's components will be all you'll need to do after most moto's as or rides as you or the rider will likely already be aware of any failures or damage long before the return to the pits but knowing what to look for can be a great help as well so these steps below should keep you in the know.
Considering the conditions that the front brake pads on a dirt bike are subjected to such as mud, sand and extreme heat, it really should be no surprise that the brake pads, hardware and brake rotors would and can frequently develop and show wear. This coupled with the fact that a lot of riders know that dragging the front brake through a turn can make the motorcycle perform and handle better by aiding in the front wheel's traction but doing so causes accelerated wear of brake pads and brake rotors among other parts so here's what to look for after each ride:
How do you know if you have a fixed or floating caliper?
- Inspect the hydraulic system for adequate pressure or leaks:
This can be easily done by merely grabbing the front brake lever and squeezing it to check for adequate pressure at the lever and visually inspecting the front brake system from the master cylinder to the caliper for any signs of wetness or dirt accumulation. If the brake pressure doesn't feel adequate by a soft brake lever or a lever that goes to the handle bars, the front brake pads may either be worn way beyond their service limit or there is air trapped in the hydraulic system which can be addressed by bleeding the brakes and getting new, clean brake fluid into the front brake master cylinder or caliper.
- Inspect the brake rotor for grooving, heat marks or other damage:
When checking the brake rotor, you also want to look closely for any heat cracking, discoloration, grooving or other unusual damage. Should any damage to the brake rotor become evident, the only remedy that should be considered is replacement of the brake rotor at which time you may even want to consider an oversized replacement brake rotor, as an oversized rotor from a company such as Braking or EBC can further increase the motorcycle's stopping abilities and performance.
- Is the brake rotor bent?
Front brake rotors do get bent occasionally when running into the swingarm of the guy in front of you or with another rider or by other natural means such as rocks, stumps and the like. An effective means of checking the flatness of the front brake rotor is to place the dirt bike on a stand with the front wheel off the ground and spin the front wheel lightly by hand while watching for any dragging spots when the brake rotor rotates through the brake pads. The brake rotor's flatness can also be checked by riding the bike in a smooth area and applying the brake lever while feeling for any pulsation which may indicate a warped brake rotor.
- Inspect the brake pad friction material every ride.
By far, the highest wear item on the dirt bike's front brake system is the brake pads themselves, and depending on the compound you're running, and level of use, brake pads can be through dealing in no time depending on conditions such as mud or hard and aggressive use.
Anytime you inspect the brake pads thickness you want to be looking for a wear indicator that is almost impossible to see or find most of the time. A better way to check a pad's thickness to determine the usability remaining in the brake pad is to take a close visual inspection and note the thickness of the friction material. If the brake pad's friction material is equal to or less than the thickness of the pad's backing plate at any point on the pad, you can consider the front brake pads to be in need of replacement, so, to ensure the best performance and not boil the brake fluid or have any factors contributing to brake fade, the front brake pads should be replaced.
If the brake pads are removed for other reasons, inspect them for any glazing, cracking or other irregularities in the pad's friction material. If any glazing or other irregularities are noted, replacement of the brake pads as a set should be the only option to consider as well.
- Ensure the front brake caliper slides are not frozen
On most dirt bikes the caliper is intended to "float" while the rotor remains fixed although on some models, the brake rotor floats. There are distinct differences between the fixed and floating which are
- A fixed front brake caliper would be firmly attached to the lower fork leg lug with no movement, yet the front brake rotor would appear to be made of multiple pieces so as to allow very slight brake rotor movement.
- A floating front brake caliper would be evident upon inspection, as the brake rotor would be solidly attached to the front hub and the caliper mounted on a bracket slides bolted to the lower fork leg vs the caliper itself.
Once you've determined the style of front brake on the motorcycle being worked on, check to ensure that either the caliper or brake rotor has very slight side to side movement (either of which may feel like slop to the inexperienced) Also, be sure to lubricate the caliper slides while checking them for wear the next time you have the caliper and caliper bracket off.
How to Replace the Front Brake Pads on the Bike
Replacing the front brake pads on a dirt bike is a common procedure that most anyone can do themselves and reliably keep their steed coming down from warp something to a much more manageable speed so we wanted to hook you up with the quick rundown on how to do this like a pro, as well as what to look for so you can out run the competition by out braking them or just have a dirt bike that slows properly.
- The first step to changing the front brake pads on the bike is to ensure that the entire area is clean and the best time to do this is after washing the dirt bike. If you're going to be replacing the brake pads between moto's or while testing such as at the track and washing the dirt bike isn't really feasible, be sure to clean as much dried dirt or mud away as possible from the braking system with your fingers, a brush and / or compressed air.
- With the area clean around the front brake caliper, place the box end of a wrench the appropriate size (most likely an 8mm) over the bleeder then a tube to a bleeder bottle as can be easily made with 1/8 inch clear tubing and an empty water bottle, then loosen the bleeder.
- With the bleeder open, use a pair of channel locks and very carefully squeeze the inner pad inwards pressing the caliper pistons back into their bores, forcing the brake fluid that's in the caliper out and into the bleeder bottle for disposal later. Continue working the pads into their bore by only squeezing the inner pad itself but do NOT start cramming screwdrivers between the pads & rotor.
- With the caliper pistons fully retracted, you'll need to close the bleeder and remove the brake pin to allow the front brake pads to be removed from the caliper, so you'll either have to carefully remove clips securing this pin, or remove the threaded plug on the side of the caliper near the bottom as this enables access to the pin that the brake
pad slides on, then remove the brake pin.
(Some bikes may have an external hex as either an aftermarket replacement part or it may have come this way from the motorcycle manufacturer. This style reduces this to one piece eliminating the plug.)
After removal of the brake pin, be sure to inspect the pin for any grooves, bending or wear. If any wear is evident on the brake pin which was just removed it's important to install a replacement brake pin,
otherwise the brake's performance will likely suffer.
- With the pin removed, the brake pads should now come out the bottom of the caliper just be sure to not lose any shims that may be in place directly opposite of the pin as these may shift or fall out after removal of the brake pads.
Should there be a piece fall from the end opposite of the brake pin, be sure to bend the tabs on this which keep it secure in the caliper or caliper bracket and reinstall these, as these prevent the aluminum bracket from developing grooves which may cause the brakes to stick and bind.
- With the old pads out, insert the new pads back into the caliper using the same orientation as what came out and ensuring the friction material is facing the rotor's surface. (you'd be surprised what some might do otherwise.)
- With a new brake pin, or using the existing pin provided it was in good shape when you removed it, place a small amount of anti-seize on the threads only (if threaded), then replace the pin ensuring it is securing both pads properly and either tighten the pin securely or install the retaining clips to secure the brake pin the way that the manufacturer recommends as be found in a factory service manual specific to the motorcycle being serviced.
Do NOT use any lubricants on the sliding part of the brake pin
New Brake Pads Do Require A "Bed In" Period.
Installing new pads often results in terrible performance front the front brake's stopping abilities which can last for a mile or 3 until the "feel" comes back into the lever. This is because it takes time for the pads to become matched to the rotor ("Bedded In").
How To Bed In New Brake Pads
To Bed In a set of brake pads is really no big deal. Here's how:
Ride the dirt bike around for a few minutes in a flat and smooth area holding the gas and brake simultaneously while gradually increasing the drag of the brake for 20-50 feet and releasing for a cool off then repeating.
Do this a few times and the feel at the lever should immediately feel stronger. Once the pads are able to grip the rotor well enough to throw a stoppie with minimal effort on the lever, the pads could be considered well "Bed In"