November 2009 Technical Corner

Let's talk about the most important safety device on your Gold Wing — your brakes! Almost all motorcycles have brakes! Your Gold Wing has hydraulic disc brakes on both wheels. The hydraulic system can be a real troublemaker if routine maintenance is neglected.

Brake lockup is a common problem that can happen if you let your brake fluid get so dark in color that it looks like coffee. (It doesn't matter if it's regular or decaffeinated!) DOT 3 and DOT 4 brake fluids are very chemically thirsty. In other words, these fluids will suck up all the moisture that they can and leave it in the hydraulic system. In our humid climate, there's plenty of moisture and your brake fluid will find it and drink it up even if your system is supposedly sealed. That's why your brake fluid gets brown. The brown stuff is actually microscopic pieces of rust suspended in the brake fluid. If enough rust particles stop up the return orifice (approx. the diameter of a human hair) you will eventually experience brake lock-up.

Refer to your maintenance schedule in your owner's manual for brake system maintenance intervals.

NEVER add brake fluid to your reservoir. When your reservoir level is low, this does not always mean that you are running out of fluid. It means that you probably need new brake pads. If you add fluid and then try to compress your pistons for the new pads, your reservoir could burst and spray brake fluid all over your paint and no one needs to tell you what brake fluid does to paint and plastic!

The GL 1000 Gold Wings have a dual piston fixed caliper on the rear wheel only. All other Gold Wings have floating calipers front and rear. These calipers float on two sliding bearings. One of the bearings is the unthreaded part of the large mounting bolt. The other sliding bearing is a collar held in place by two rubber bushings. If the collar doesn't slide easily in the caliper, it should be disassembled, cleaned and lubricated with brake caliper grease. Failure to maintain these sliding bearings can result in uneven pad wear or brake lock-up.

While your Gold Wing is under warranty, use only what American Honda recommends for replacement pads and brake fluid.

Now let’s talk about bleeding your brake and clutch hydraulic systems.

You may have experienced a soft or spongy feel in your brake pedal, brake lever, or clutch. All 1975-1983 Gold Wings have a cable operated clutch. All 1984-present time have hydraulic operated clutches. Usually, long term storage will cause spongy brake and clutch levers.

If you feel that your clutch has a soft spongy feel, the system probably has an air bubble trapped at the banjo bolt fitting at the master cylinder. The most effective way to bleed the air out of the system is to use a Mity-Vac®.

HOWARD’S MITY-VAC®

This is what a Mity-Vac® looks like. I find it to be quite a handy tool for testing vacuum diaphragms as well as bleeding hydraulic brakes and clutches.

Put the Gold Wing in its center stand and place plenty of protective rags around and below the master cylinder. Remove the cover from the master cylinder reservoir and fill the reservoir with fresh DOT 4 brake fluid. Connect the Mity-Vac® to the bleeder valve at the slave cylinder. Pump the Mity-Vac® to a vacuum reading of approx. 20 in. Hg and open the bleeder valve. You will observe fluid and perhaps some air bubbles flowing into the Mity-Vac® canister. Close the bleeder valve and test the clutch for firmness.

The Mity-Vac® procedure for the brake system is similar. However, if you do not have a Mity-Vac®, you can still bleed the clutch and front master cylinder with the following alternate method. This method will not work with the 2001 and later Gold Wings.

If you own a 1984-2000 Gold Wing, put the Gold Wing in its center stand and place plenty of protective rags around and below the master cylinder. Remove the cover from the master cylinder reservoir and fill the reservoir with fresh DOT 4 brake fluid.

Use a box end wrench and loosen the banjo bolt, then slightly snug it up. Squeeze the lever, holding pressure on the lever. Loosen and snug the banjo bolt. Repeat the procedure until you hear no more air and the lever feels form. If you own a 2001 or newer Gold Wing, you would be best to see your authorized Honda dealer for clutch bleeding. For front brake bleeding, you can bleed the system at the brake bleeder valves, but we highly recommend that you see your authorized Honda dealer service department due to the complexity of the brake systems on the GL1800s.

Howard Halasz, Technical Coordinator

GWRRA Spring, Texas Chapter M-2

Chapter M-2's Technical Corner