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Common Tread

This tip could save you a fork seal replacement job

Dec 03, 2015

I am becoming antiquated, like a 35 mm camera.

That is a great irony, because the tip I’m about to share is actually becoming more relevant on modern motorcycles, and uses a staple of the 35 mm camera world: film. Remember that stuff?

I was standing around the water cooler with a colleague who was suffering a leaky fork seal, and I asked if he tried the film trick. All I got was a blank stare, so I explained it to him. Later, back at my desk, I asked our lead video editor if he knew what the hell I was talking about. He’s a few years younger than I am, but he used to ride dirt, and I thought all dirt riders did this. Another glazed look.

So let me get to the meat and potatoes of what I am yammering on about: If you are suffering a leaky fork seal, the fix is usually a new seal. Seals are cheap, but as anyone who’s performed the task can tell you, the job is kind of a pain in the ass. Before you start ripping stuff apart willy-nilly, try this easier way to get the oil to stay inside the fork tubes.

Sometimes, crap becomes lodged between the seal lip and the fork slider. (That’s why this tip used to be common knowledge among dirt riders.) Often, dislodging whatever detritus is trapped between the rubber seal and the fork tube is enough to allow the seal to once again lie against the inner slider. Abracadabra, good as new!

First, get the gaiters off if you have them... RevZilla photo.

It’s easy to do. Cut off a chunk of 35mm film. Pop your dust boot up. Gently slide the film between the seal and the fork tube. Work it around the seal, up and down, until you get back to where you started. Done.

Then pry up the dust seals carefully. RevZilla photo.

What if, for obvious reasons, you don't have any film handy? I’ve used feeler gauges, plastic, and even a business card to do this on the road. If you can use something softer than the sealing material, that’s the way to go. Using something like a feeler gauge increases the chances of tearing the delicate seal material, but sometimes you gotta do what you gotta do.

Slide the film between the oil seal and the stanchion. Work it gently around the circumference of the seal, and odds are excellent that any debris that's been allowing fluid to pass will be displaced. RevZilla photo.

Remember how I said this trick is more relevant now than ever before? That's because many modern forks are upside-down. Because of that, the reservoir holding the fork oil is entirely above the seal, rather than below it as in a conventional setup. What that means is that a) gravity is helping your leak move faster, even when the bike is parked and b) it’s more likely to contaminate your brake pads. Just when DSLRs are at their cheapest. Rats.

Some of you probably already knew this little procedure. If I saved the rest of you an unnecessary teardown, you're welcome.