Throwback Thursday: Upgrading Your Fork Seals To SKF

One of the unsung heroes of the modern mountain bike is the lowly fork wiper. It’s a small part, but it makes a huge difference in the way your suspension feels, and it needs to be replaced more frequently than you might expect. Time and time again we encounter riders who have run their forks into the ground by not changing wipers or the lubricating bath oil that keeps a fork running smoothly.

Fork seals have to function in a very demanding environment, and while fork manufacturers have worked hard to improve their own seal systems, SKF has developed a range of aftermarket seals tuned to reduce friction, improve suspension feel and increase the life of the fork. SKF seals are said to be better at sealing out water and dirt, which keeps lubrication oil cleaner over the life of the seal. We put a set of these seals through the wrecking crew wringer, but first we had to install them.

This procedure is for a Fox 36 RC2 fork, although it’s very similar to the installation procedure for most major brands. If it’s been a season or more since your last suspension service, whether or not you choose to upgrade to an aftermarket seal like the SKF, it’s time to show your bike some love. We’ll show you how.

Editor’s Note:  In this Garage Files article, published in the last issue, we forgot to mention that FOX forks have come equipped with SKF seals since 2011. FOX recommends using genuine FOX SKF seals that are available at your local dealer or calling 1-800-FOX-SHOX

Start by removing the fork from the bike. While it is possible to do this operation without this step, it’s much easier this way.
Start by removing the fork from the bike. While it is possible to do this operation without this step, it’s much easier this way.
If you have a bike repair stand, clamp the fork’s steerer tube in the stand.
If you have a bike repair stand, clamp the fork’s steerer tube in the stand.
Remove the air cap (if applicable) and release all the air pressure from the fork.
Remove the air cap (if applicable) and release all the air pressure from the fork.
Remove the protective cap from the rebound knob.
Remove the protective cap from the rebound knob.
Use a 2-millimeter Allen wrench to loosen the set screw on the rebound knob and remove the knob.
Use a 2-millimeter Allen wrench to loosen the set screw on the rebound knob and remove the knob.
Use a 15-millimeter wrench to remove the foot nut from the right fork leg.
Use a 15-millimeter wrench to remove the foot nut from the right fork leg.
Use a 10-millimeter wrench to remove the foot nut from the left-side leg.
Use a 10-millimeter wrench to remove the foot nut from the left-side leg.
Use a socket over the rebound knob to protect the delicate rebound adjuster knob. Then use a hammer to tap the rod free from the lowers of the fork.
Use a socket over the rebound knob to protect the delicate rebound adjuster knob. Then use a hammer to tap the rod free from the lowers of the fork.
If you’ve done this right, there should be some oil that pours out of the fork leg. Use an oil-catch pan to keep your garage floor clean.
If you’ve done this right, there should be some oil that pours out of the fork leg. Use an oil-catch pan to keep your garage floor clean.
Now, tap the left side in a similar fashion to break it free from the fork legs. More oil will pour out of this side too.
Now, tap the left side in a similar fashion to break it free from the fork legs. More oil will pour out of this side too.
With both rods free, you will be able to remove the lowers from the fork.
With both rods free, you will be able to remove the lowers from the fork.
Clean the damper rods and upper tubes with a clean paper towel.
Clean the damper rods and upper tubes with a clean paper towel.
For good measure, wipe any excess dust from the seals, being careful not to spread dirt into the lowers.
For good measure, wipe any excess dust from the seals, being careful not to spread dirt into the lowers.
Use an open-ended wrench as a lever to remove the dust wipers from the fork.
Use an open-ended wrench as a lever to remove the dust wipers from the fork.

 

Once the dust wipers are removed, remove the foam rings.
Once the dust wipers are removed, remove the foam rings.
Thoroughly clean the lowers with isopropyl alcohol and a clean paper towel
Thoroughly clean the lowers with isopropyl alcohol and a clean paper towel
Get your SKF seal kit ready.
Get your SKF seal kit ready.

 

Using 20-weight Fox suspension oil, thoroughly lubricate the new foam rings.
Using 20-weight Fox suspension oil, thoroughly lubricate the new foam rings.
Find an appropriately sized seal press. This 36-millimeter fork works well with a standard bottom bracket tool. An appropriately sized tool will fit nicely over the springs and only press on the outer rim of the seal.
Find an appropriately sized seal press. This 36-millimeter fork works well with a standard bottom bracket tool. An appropriately sized tool will fit nicely over the springs and only press on the outer rim of the seal.

 

Lightly lubricate the lower half of the new seal.
Lightly lubricate the lower half of the new seal.

 

Install the soaked foam rings.
Install the soaked foam rings.

 

Use the seal press to evenly press in the new seals. This should be fairly easy to do and should not need more pressure than with your hand.
Use the seal press to evenly press in the new seals. This should be fairly easy to do and should not need more pressure than with your hand.

 

Ensure that the seal is fully installed and bottomed out on the lowers.
Ensure that the seal is fully installed and bottomed out on the lowers.

 

Replace the lowers on the upper tubes.
Replace the lowers on the upper tubes.

 

It’s easy to pinch the foam rings in this process. If there’s any resistance, it’s better to pull off the lowers and start again.
It’s easy to pinch the foam rings in this process. If there’s any resistance, it’s better to pull off the lowers and start again.

 

Invert the fork in the bike stand.
Invert the fork in the bike stand.

 

Pour fresh oil into a syringe. For the right side, this fork requires 30cc, and the left side requires 10cc. This level will vary between manufacturers and models, so check the company website for the exact fork oil levels.
Pour fresh oil into a syringe. For the right side, this fork requires 30cc, and the left side requires 10cc. This level will vary between manufacturers and models, so check the company website for the exact fork oil levels.

 

Use the tip of the syringe to pour the oil into the bottom of the fork legs
Use the tip of the syringe to pour the oil into the bottom of the fork legs

 

Place the plastic crush washers included in the seal kit on the corresponding fork-leg rods.
Place the plastic crush washers included in the seal kit on the corresponding fork-leg rods.

 

Be sure to use a pick to pull out the old crush washers from the foot nuts.
Be sure to use a pick to pull out the old crush washers from the foot nuts.

 

Use the open-ended wrenches to tighten the foot nuts.
Use the open-ended wrenches to tighten the foot nuts.

 

It’s easy to over-tighten these foot nuts, and it’s best to use a torque wrench, although many will forgo this step.
It’s easy to over-tighten these foot nuts, and it’s best to use a torque wrench, although many will forgo this step.

 

Replace the rebound knob on the right side and re-tighten the 2-millimeter set screw. Be sure to align the bolt with the groove on the rebound rod before tightening.
Replace the rebound knob on the right side and re-tighten the 2-millimeter set screw. Be sure to align the bolt with the groove on the rebound rod before tightening.

 

Replace the protective cap.
Replace the protective cap.

 

Re-pressurize the air spring.
Re-pressurize the air spring.

 

Enjoy your buttery-smooth new seals!
Enjoy your buttery-smooth new seals!

 

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