Leaking Fork Seal? A Quick Guide on What to Do

Your stomach drops the minute you see even the tiniest trace of fork fluid on your fork hose. You know it's only a matter of how long before a gusher bursts from your fork cap. As a result, the suspension will behave like a pogo stick with no damping. To make matters worse, the fork oil will undoubtedly soak your front disc brakes. You will have another safety problem to contend with, on top of having to add fresh brake pads to your suspension bill at the garage.

Natural tear and wear, age, and contaminants getting into the seals cause fork seals to leak. Chrome flaws and nicks can also cause your fork seals to leak. However, the rest of the time when your fork seals leak, it's probably because debris has become lodged in the seal, keeping it open and allowing fork oil to pass through.

What Is the Role of Fork Seals?

The suspension on today's motorcycles is absolutely incredible. Over 100 years of development of motorcycle design has resulted in the amount of movement they have and the parts within that regulate the speed of compression and rebound.

Any use of oil as a speed regulating medium in the suspensions is one of the reasons why today's suspension is so fine. The task, however, is to keep the oil where it remains while still allowing the spring to move up and down thousands of times. Also, under high pressure during swift compression, the only thing keeping the oil in is a small "lip" of rubber called the fork seal.

To put it simply, this tiny "lip" lies between the outer and inner fork tubes. As you would expect, the link between the inner fork tube and the oil seal must be flawless in order to avoid oil leakage. The oil seal can no longer keep the oil from leaking if it becomes old or rough.

What Can Be Done to Repair Fork Seals?

Aside from removing the seals, there are other things you can do to repair your fork seals and get back to racing in no time. If you are unable to do it yourself, you can have your bike serviced by a trained bike mechanic. Based on how many pieces need to be repaired, replacing fork seals will cost between $100 and $200.

Change Fork Seals

Fork seals should be checked after 40 hours of traveling, or every 2 years if you don't drive frequently. Even if you wash the seals on a regular basis, they will inevitably tear and leak regardless of what you do to maintain it. If you don't know how to fix a fork seal and wiper set, take it to your nearest bike dealer or make friends with a mechanical minded moto-buddy and learn from them.

To complete the project on your own, you will need specialized equipment such as fork seal drivers. These tools can be costly and tailored to your particular bike or fork size. A ride to the garage to repair this problem is also costly. 

Lift the Dust Covers and Clean Below Them

If you know what you've been doing, gently pry the dust seal apart with a flathead screwdriver, taking care not to damage the fork or harm the seal. Clean out any dirt or debris trapped under the lip with a lint-free cloth or a cotton ball before reassembling it.