Give me a brake! brake maintenance tips

Did you know that your brake fluid in those fancy, modern, high-tech disc brakes on your machine is a maintenance item?  I bet you also didn’t realize that it needs changing at regular intervals.  In this article I will discuss why its important, my preferred method of flushing and bleeding the brake system, and some other parts to inspect or replace during these processes.

A comparison between new and old brake fluid, respectively

First off this tip is more for the seasoned machine, machines that are at least 1 or 2 years old.  Brake fluid is one of those things that is commonly overlooked on automobiles and certainly on ATVs.  It just sits in the system dutifully doing its job, rarely giving you any warning that its tired and worn out until other more expensive problems (and safety concerns) arise.  Brake fluid has a very short “pot” life, once it has been exposed to the atmosphere is begins to degrade.  Water is naturally attracted to it and saturates is breaking it down and thus making it more corrosive to internal braking components.  Furthermore brake fluid has the tough job of transferring heat from the pads storing it to dissipate it later.  This heat cycling lowers the boiling point over time.  If your hard on your brakes the fluid can actually boil separating it and ultimately degrading any rubber parts such as the insides of the brake hoses.

The safety concern comes in with the brake hoses.  Over time the hoses can collapse inside causing one of two different situations.  First they can collapse after the brake has been applied, preventing the fluid from flowing back to the master cylinder after the brake has been released.  This will cause the calipers to drag or stick “on”.

This is exceptionally dangerous on ATVs with independent wheel braking found on the front of ALL sport and race ATVs as well as many utility type machines.  Basically this means the one wheel could lock while the other wheel is free to spin after the brakes are released, causing a spin or roll over.  In this case the lever will feel mushy or not fully return.

The other condition works the opposite where the brake line collapses before the brake is applied thus preventing the fluid to reach the caliper.  The result is the caliper moves only slightly or not at all to apply pressure to the rotor and slow the machine down.  In this case the lever will feel hard and not move very far or not at all.

Now that you know some of the consequences of not maintaining your brake fluid, lets move on to my preferred way to flush and bled the system.  First lets outline the tools needed.

Large syringe

6 mm wrench (or what ever size fits your bled screws)

3/16 hose approx. 2 foot

Dot 3 or 4 brake fluid (check your service or owners manual for proper spec’d fluid)

One word about brake fluid.  Always use new fluid from a seal container, if the container is more than 6 months old and previously opened, throw it out and buy some new fluid.  It is cheap insurance against contamination.

The procedure is pretty simple.  Start by draining your master cylinder by either  removing the line or sopping up the fluid with a clean rag.  Put your wrench on the bled screw and install the hose on the nipple.  Fill the syringe with fluid and thump it to remove the air bubbles.  Crack open the bled screw and slowly push the fluid into the system.  This does two things, it back flushes debris out of the caliper and it also pushes air up and out of the entire system.  Most systems will probably need 3 syringe fulls.  Make sure you do not push air into the system, close the bled screw each time you refill the syringe.

With some patience and practice you can change out the fluid in your system in less than 20 minutes.  A good rule of thumb is to change your fluid every 2 years at the minimum, but if you ride hard and frequently heat up your brakes I would change it every season.

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