Disc Brake Tech
How-To Revitalize and Maintain Your Disc brakes
Most of us can't afford to run out and buy a new bike every time something goes wrong or needs adjusting. So as consumers, we are familiar with the ever-so-painful and expensive trip to the local dealership or mechanic.
You may have pondered the idea of performing simple maintenance tasks on your own, but may be overwhelmed with questions and the possibility of making things worse than they already are. Well fear no more because when it comes to disc brakes, they're all pretty much the same and reasonably easy to tackle by the average do-it-yourselfer. However, you must use a great deal of caution when dealing with brakes because of how important they are to safety. If you don't feel comfortable working on your brakes by yourself, then by all means have someone with more knowledge and experience help you.
Whether you ride a sportbike or a modern cruiser, the elements in the braking
First and foremost is making sure there is no air in the hydraulic system. Air is your enemy and can get you into serious trouble if the necessary precautions are not taken. The second most important aspect of your motorcycle's braking system is the amount of friction material on your brake pads. As you use your brakes, the material is slowly burned away in order to provide enough friction to stop your motorcycle. The third most important aspect is the condition of your brake fluid. Brake systems are not set-and-forget items on your bike. As the fluid gets old, it starts to degrade and absorb moisture, reducing its ability to perform its job.
When it comes to disc brakes, they're all pretty much the same and reasonably easy to tackle by the average do-it-yourselfer.
Replacing stock or worn brake pads is the quickest way to get increased braking power out of a tired system. Various manufacturers make all kinds of different types of replacement brake pads for today's motorcycles. Some claim to last longer, while others claim to give more feel and braking power. However, be forewarned that the manufacturer of your motorcycle put a lot of time and effort into developing your braking system, and there is no telling what a different type of pad material might do to your rotors or how well different pads will work with the overall design and setup of your bike. If you have any doubts, then stick with genuine factory parts.
Once the new pads have been assembled into the calipers and everything is torqued to spec, it is time to bleed the lines. In order for the hydraulic brake system to function properly the entire system must be fully pressurized without any air or moisture. If air and/or moisture are present in the system, it can cause a "soft" or "spongy" feel to the pedal when applied. Air can really mess things up, as it is compressible and can allow excessive pedal travel and loss of braking pressure. Moisture in the fluid will boil causing the same conditions and will also contribute to corrosion of internal brake components.
There are several different techniques to bleeding brake lines. Some of the more popular ideas are outlined below.
The Old Fashioned WayThis method of bleeding your brake system can work if you absolutely don't want to spend any money to make things easier on yourself. The basic idea is to have two people, one puts a light amount of pressure on the brake lever to introduce pressure into the system while the other opens the bleeder screw on the caliper and closes it after a couple seconds, thus purging the system of a little bit of fluid and air. As easy as it sounds, it is very difficult and time consuming to completely flush out all of the old fluid and the air bubbles from the system without getting out of sync with your partner and sucking more air into the system.
The Easy WayFor not a lot of money one can purchase a couple simple devices that will ease the painful process of brake bleeding. The first (and cheapest) is a simple little spring operated valve mechanism that attaches to a plastic hose from the bleeder screw on your calipers. This valve acts as a one-way bleeder that lets fluid and air out and closes before outside air can be sucked back into the line.
Since I like to be as efficient as possible, I opted for the vacuum bleeder method. I purchased the MityVAC Vacuum Brake Bleeder for $28 from my local automotive parts store. It essentially is a hand-operated pump with a small reservoir attached to collect the old fluid. There are more expensive and sturdier units available. But I don't intend to use this often (maybe a couple times a year), so I figured the cheap one would do fine.
Once you have sucked out all the old fluid, pour your new fluid into the master cylinder and begin to bleed the system. If you choose to use a vacuum brake bleeder as I did, keep in mind to read all of the instructions carefully. I had very little trouble using my vacuum bleeder, in fact the entire process took less than 15 minutes to finish. Life is so much easier when you have the proper tools.
Keep in mind to watch the level of fluid in the master cylinder as to not let it get too low and suck air into the system. It sounds simple enough, but I have seen people have to start completely over because they were in a hurry and didn't remember to refill the reservoir.
There should be a distinct difference in color between the old fluid and the new fluid. Once, you see only fresh fluid emerging from the bleeder screw the system has been completely flushed. As far as getting all of the air bubbles out, gently tap on all of the fittings in your brake lines to free all of the air bubbles that might have gotten stuck there. Then make sure that the master cylinder reservoir is topped off with enough fluid, install the caps, replace the rubber covers over the bleeder screws, and you are finished.
Double check to make sure that the pads are securely held in place and the calipers have been torqued correctly to their mounting locations.
Now, before you run out and test your brakes on the road it is a good idea to pump the brake levers to make sure that there is sufficient pressure in the system. Also, roll the motorcycle slowly and test the front and rear brakes before you hit the road. Double check to make sure that the pads are securely held in place and the calipers have been torqued correctly to there mounting locations.
New pads usually require a certain amount of break-in for them to function correctly. Check with the pad manufacturer for proper break-in times and procedures. If you upgraded pad materials from your previous type, keep in mind that there is probably going to be a noticeable improvement in stopping power and initial bite. Take time to get used to your new setup so you don't hurt yourself or your precious motorcycle
More by Michael Kresnicka
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