Brake Fluid Change and Flush - What's the big deal and why every two years?

They say a picture is worth a thousand words…

Brake fluid change is a topic that has been generating discussion lately when previously, most riders ignored the service interval in the owner's manual.  The debate really took off when Harley was forced to recall motorcycles due to water getting into the ABS unit freezing the pistons, and now everyone recommends the two-year/24k miles replacement of fluid regardless of miles or condition of the existing fluid.

Let me start with some simple facts. Dot 4 Brake Fluid has a “dry” boiling point of 446 °F. Dry refers to fresh, brand new brake fluid. It has a “wet” boiling point of 311 °F. Wet is when it has absorbed 3.7% water by volume. Basically a few drops of water/moisture can drop the boiling point drastically.

Now let's talk Harley-Davidson motorcycles. Many of the rear brake master cylinders are located directly next to the exhaust, which we know is hot, then add that brakes can develop a substantial amount of heat, particularly when used repeatedly, and you get to at or above the boiling point very quickly.

So now that we have a little understanding, add in that if you remove the cap covering the master cylinder reservoir you introduce air which contains moisture. Plus, water can get in through the microscopic pores in your hydraulic lines.  Once water gets into the system it can theoretically float to the top and to the highest point in the system, which many times is the ABS unit. Once there, it leaves deposits that can stick to the valves that actuate the ABS system defeating its purpose. On older non-ABS systems this water typically traveled to the master cylinder which is the highest point in the system which is why this really wasn’t such an issue in pre-ABS motorcycles.

Much more can be written about this topic but the safe choice is to change it every two years/24,000 miles. We also recommend it get changed any other time work is performed in the brake system.

Motorcycle Tire Pressure- Why its important to check!

One of the many checks performed before a customer picks up their motorcycle is to make sure the tires are at the factory recommended pressure. About 95% of the time we find tires lower than recommended and even more worrisome is the fact that of the 95% at least 80% of those are 10-15 PSI low. On a car that would be low but on a motorcycle it is dangerous.

We routinely ask our customers about checking tire pressure, and the response ranges from “I check it before a big ride” to “it was checked the last time you guys checked it.” Tires can quickly lose 1-3 PSI per month, so tire pressure can get to a critical point quickly.

The primary point about checking tire pressure is to take a look at your motorcycle tires. The tire manufactures have designed tires to have a specific contact patch. The contact patch is the portion of a tire that is in actual contact with the surface. Look at the point your tire comes in contact with the road. Measure that spot both length and width to come up with the square inch area of the contact patch of your tire. Not much right? Well, that’s all that is keeping you right side up. If you have an under-inflation issue, you deform the contact patch geometry, and of you over-inflate you are now minimizing the contact patch.

We recommend checking your tire pressure before every ride.

1. Check your owners manual and know what your tire pressure should be set to both single and with a passenger.

2. Most modern motorcycles have a manufacturer label on the frame, under the seat or other location that states the tire pressure(many even give the proper tire size). If the label is not easily visible, make a note within your phone notepad app of the tire pressure (Both front and rear), and no, the sidewall pressure marked on your tire is not your tire pressure! On touring motorcycles, we place a label inside the trunk with the proper pressure and if applicable the air pressure for the suspension ( again both single and with a passenger).

3. Get two good quality tire pressure gauges. (One for home use and one for travel.) Depending on the location and ease of access of your valve stem, you might need to try a few different ones until you find the one that works for your motorcycle. Check out these two Digital Tire Pressure Gauges. Both have lighted displays, so they are easy to read

Motion Pro 08-0648 0-60 PSI Digital Tire Pressure Gauge: https://amzn.to/2ns7DEL

TEKTON Instant Read Digital Tire Gauge: https://amzn.to/2nAii0l

4. Always check your tire pressure cold. Heat will raise the pressure reading.

5. Set it to the manufacturer recommended pressure and then adjust for your riding conditions.

6. Put the damn valve stem cap back on. It really serves a purpose not just to cover the threads.

When traveling, don’t be afraid to stop by a local shop to have your tires checked out. Most motorcycle shops will help you determine the proper pressure and like us, will let you use our gauges and air lines to perform a quick check. Poor tire inflation can ruin a ride.