Seal healers – the tool you never knew you needed

Fork seal leaks are unhappy discoveries. First, fork oil has already escaped and must be cleaned off the fork, and possibly the wheel, disk and brake caliper/pads, too, depending on how the oil may have flowed and dripped. Then there’s the fact the oil level inside the fork has now dropped by some unknown amount. Optimal fork performance depends on this level being set properly and equally in both fork legs, so the oil level will have to be measured and reset—a task which on most bikes requires fork leg R&R. This could be further complicated by the possibility that contaminants, such as dirt or water, may have entered the fork through the same opening that allowed the oil’s departure. If such a possibility is to be addressed, a complete fork oil drain, flush and replacement may be in order, which in most cases will require more thorough fork disassembly—and we haven’t even gotten to any problem with the seal itself!

The good news is there may be nothing wrong with the seal. The vast majority of such leaks result from a tiny bit of debris getting lodged under the seal’s lip and propping it away from the chrome stanchion it otherwise hugs tightly. Many fork seals get replaced unnecessarily, when only a little cleaning is actually needed.

The time-honored method of cleaning a fork seal is to use a short piece of 35mm film (remember when cameras held film?), cut so it has a slightly hooked shape at one end. With the forks still on the bike, the dust scraper is pried out of the large tube and slid out of the way. All external surfaces nearby are then wiped clean, including the cavity between scraper and seal. The film, coated with a little fork oil or silicone lubricant, is then wrapped around the stanchion at an angle, so its “hook” can be slipped under the seal’s lip. The film is then rotated around the full circumference of the seal a couple of times, thereby dislodging the debris and allowing it to be flushed clear of the seal by a little more oil, which gets liberated in the process. NOTE: This only works when the stanchion is below the large tube, so gravity pulls the debris out of the large tube, instead of into it. We’re talking about modern “upside-down” forks (are they really upside-down, now that they’ve become the norm?), or old-school fork legs that have been removed and inverted.

If caught quickly enough, the amount of oil lost in a minor leak may be insignificant to all but the most perfectionistic owner – at least it’s not worth the trouble/expense of fork disassembly. The same goes for potential contaminants.

Since most of us no longer have 35mm film just lying around, here are two purpose-built solutions to try instead, both of which work better than film anyway.

Motion Pro Seal Mate

At $7.50, this “tool” is absurdly expensive for what it is (merely a stamped-out sliver of flimsy plastic), but incredibly cheap for what it does. Before replacing seals, use a Seal Mate to “floss” the seal/stanchion interface by slipping its hooked end under the seal lip, and easing it gently around the fork tube’s circumference before extracting it along with the mischievous, leak-causing crumb. In most cases, the problem is solved in under a minute. If not, at least you know the next two hours of labor to install a new seal are truly necessary. Seal Mates are basically the old film remedy with a couple improvements: A) you don’t have to shape the film yourself, and B) the edges are less likely to accidentally cut the seal’s delicate rubber lip because they’re not as sharp or rigid. One Seal Mate has saved me many afternoons playing fork mechanic, not to mention liters of fork oil and a half-dozen replacement seals. On this basis, the Seal Mate’s purchase price represents an outstanding value. Not only have I been able to easily stop a leak discovered at home, I’ve caught them out on the trail before more oil was lost and/or more contaminants gained entry; Seal Mates are weightless and take up no space in a tool pack.

The only downside of using Seal Mates is they eventually wrinkle. Depending on how ham-fisted the user is and how tight the seal is, the Seal Mate’s thin plastic can buckle near the tip while being forced into place. Once creased in this way, it becomes more likely to buckle in the future and doesn’t work as well, even if it can be coaxed into the crevice between seal and stanchion. Hence, it’s prudent to buy more than one, especially if you’re paying shipping. Even with experience and care using them, I’ve found they tend to get compromised by the fourth or fifth use.

Risk Racing Seal Doctor

While three times as much as the Seal Saver, Risk Racing’s $24.99 version ends up being cheaper in the long run because it’s more durable. Their Seal Doctor is not only sturdy enough to endure countless uses, but it accomplishes the task with much greater ease and precision. Managing the free-floating Seal Mate’s position all the way around the seal can be a bit awkward, especially once more fork oil has seeped out and made everything slippery. The Seal Doctor’s user simply snaps it onto the stanchion (after moving the dust scraper out of the way and wiping the area clean), slips securely into place with its upper edge against the seal seat, and then twists. Protruding vanes supply good grip, even if things get messy, and there’s never any question about whether the working tip is the right distance or position inside the seal. It even has a little channel to guide the outflow of oil during use, and a downward-pointing tip for cleaning the dust scraper—a well-thought-out design.

The Seal Doctor is available in two sizes: large (for 45-55mm stanchions) and small (35-45mm). Each comes with a plastic tube it clips onto for storage, so pressure from surrounding items cannot collapse, bend or twist it. It takes up more space than a Seal Saver, but can still be carried along on rides if your tool pack isn’t already stuffed full. Well played, Risk Racing!

Remember, there’s always the possibility a fork seal leak could require more substantial intervention. Seals really do have to be replaced sometimes, and—if, for example, the leak is caused by a chip in the chrome tube’s plating—other parts may need attention, too. There’s still the issue of refilling/replacing that oil, depending on the size/age of the leak, recent riding conditions, and the owner’s degree of perfectionism.

Stanchion damage is most common on road-going bikes, usually resulting from stones thrown up by traffic. The resulting ding, when viewed closely, is often comprised of a tiny depression and a raised burr alongside it. The latter can nick the fork seal’s lip if it’s close enough to pass through the seal during suspension movement. Such burrs can sometimes be removed with a bit of extremely careful sanding or filing; nobody wants to foot the bill for a new stanchion! However, the associated depression may still collect oil from behind the seal and continue transporting it past, mimicking a failed seal. Off-roaders are more likely to suffer from the effects of crusty crud. Whereas wet mud is easily cleared by the scrapers before reaching the seals behind them, dried mud can take on a cement-like quality and make it through, lodging a particle under the seal lip and opening a passageway (best case scenario, and fortunately the most common), or the crust might be abrasive/sharp enough to cause real damage to the seal (worst case scenario). Especially grisly dried bug guts can do the same on street bikes.

Keep an eye on your stanchions for any sign of oil, debris or damage. Catching problems early can save you a great deal of time, money and hassle!