How to Do a Fork Lower-Leg Service at Home

A lower-leg service is the easiest way to make a tired fork feel new again, and it is the single most-DIYable job on a modern mountain bike's suspension. The procedure is the same on Fox 34, 36, 38, and Float models from 2017 onward, and substantially the same on RockShox Lyrik, Pike, and ZEB from 2018 onward. Once you have done one, you can do another in 30 minutes.

This guide walks through the full procedure for a Fox 36 or RockShox Lyrik. The steps differ slightly for other models, but the principles transfer.

Tools and parts

Before you start, gather:

• A shock pump.
• 5 mm and 8 mm Allen keys.
• A 24 mm socket on a ratchet (Fox 36 lower bolt size — confirm yours).
• A strap wrench or oil filter wrench.
• Snap-ring pliers (internal type).
• A plastic or rubber mallet.
• A clean catch pan.
• Clean lint-free rags.
• A small tray for keeping parts in order.

Fresh consumables for a Fox 36:

• Fox 36 dust wiper kit (includes seals, foam rings, oil rings).
• Fox 5wt Teflon-Infused fork oil. About 30 ml per leg for the bath. Total 60 ml.
• Fox Float fluid or comparable for the air-spring side. Skip if you are doing only the wet (damper) side bath.

Fresh consumables for a RockShox Lyrik or ZEB:

• SRAM Lyrik dust seal kit.
• Maxima Plush 0w-30 or RockShox 0w-30 lower-leg oil. About 10 ml in damper leg, 20 ml in air leg.

These parts are widely available from any suspension parts retailer. A full kit is usually $20–30.

Set up a clean workspace. A garage workbench or a kitchen table covered with old newspaper. Cleanliness matters more on this job than most.

Step 1: Prep the fork

1. Clean the fork thoroughly. Wipe stanchions and lowers with a damp rag. The cleaner the fork going in, the less dirt you will introduce during reassembly.
2. Remove the front wheel.
3. Remove any fender or accessory mounted to the lower legs.
4. Optional: remove the brake caliper and let it hang to the side. Reduces the risk of fluid contamination.
5. Note your air pressure. Write it on a piece of tape on the stanchion. You will repressurize after.
6. Release all air from the fork's positive air chamber by pressing the Schrader valve at the top of the air-spring leg. Hold it open until you hear the negative chamber equalize.

The fork should now sit fully extended with no air pressure. Pushing on the bars should compress it freely.

Step 2: Remove the lower legs

This is the part that intimidates most first-time DIYers. It is straightforward once you see it.

1. Stand the fork upside down — bars and stanchions pointing down, axle pointing up — supported in a clean workstand or against a wall pad.
2. On Fox 36: locate the bolts on the bottom of each lower leg. The 8 mm Allen on one side and the 24 mm bolt on the other.
3. Loosen but do not remove. Loosen each by 4–5 turns until the head sits about 5 mm proud.
4. Use the plastic mallet to tap each bolt back into the leg. This breaks the seal between the bolt and the internal damper or air-spring shaft.
5. You will hear a small click as each one releases. After the click, fully remove both bolts.
6. With both bolts out, place a catch pan under the fork (now upside-down, so under the axle).
7. Slide the lower legs straight off the upper assembly. Oil will drain from the lower legs into the catch pan.

If the lowers do not slide off easily, double-check that both bolts came fully out. Do not force.

Step 3: Clean and inspect

With lowers off, you have access to seals, stanchions, and the inside of the lowers.

1. Wipe down the stanchions with a clean lint-free rag. They should look mirror-finish with no scratches that catch a fingernail.
2. Inspect for visible wear at the seal contact patch. Slight discoloration is normal. A scratch that catches your nail across its width is a problem and means stanchion replacement, not just a service.
3. Wipe out the inside of the lower legs. Use a clean rag pushed in with a chopstick or similar. You are removing old oil and any contamination.
4. Inspect the bushings — they are the brass-colored rings inside the lower legs near the bottom and at the seal end. They should be smooth with no visible scoring.

If the bushings are scored or the stanchions have a deep scratch, this becomes a bigger job. Stop and consult a shop. For most riders doing service on time, neither of these is the issue.

Step 4: Replace seals and foam rings

The dust wiper kit contains new seals and foam rings.

1. Use a small flathead screwdriver or seal pick to lift out each old seal from the top of the lower leg. There are two — one at the seal-head opening and the foam ring just below it.
2. Wipe the seal cavity clean. Use a fresh rag.
3. Soak the new foam rings in fresh fork oil. They should be saturated.
4. Press the new foam rings into place at the bottom of the seal cavity. Do this by hand or with a clean tool that does not have sharp edges.
5. Press the new seals into place above the foam ring. They should seat with light hand pressure or a gentle tap with the plastic mallet on a clean drift. Do not force.

The seal lip should face downward into the leg. Most kits ship with seals oriented correctly out of the bag.

Step 5: Refill with oil

This is the simplest step.

1. With the lowers still off, hold each lower leg vertical with the seal end up.
2. For Fox 36: pour 30 ml of 5wt Teflon-Infused oil into each lower leg.
3. For RockShox Lyrik: 20 ml of 0w-30 in the air-side lower, 10 ml in the damper-side lower. The air side gets more.

Use a small graduated syringe or measuring cup. Get the volume right — too much causes hydraulic lockout, too little leaves bushings dry.

Step 6: Reassemble

1. Hold the upper assembly (bars and stanchions) vertical with stanchions pointing up.
2. Slide the lowers onto the stanchions slowly. The seals will catch on the stanchion edges — go gentle. Once the seals are seated on the stanchions, the lowers slide on cleanly.
3. Push the lowers all the way down until they bottom out against the upper assembly.
4. From the bottom, thread each bottom bolt into its respective shaft. Hand-tight first.
5. Torque to spec. Fox 36: typically 50 in-lb on the 8 mm side, 50 in-lb on the 24 mm side. Confirm in your fork's service manual.
6. Repressurize the fork to your noted air pressure.

The fork should now compress smoothly with no audible stiction at the seal. Cycle it through full travel a few times by hand to distribute oil.

Step 7: Recheck

After reassembly, before riding:

1. Recheck sag. The new seals will move slightly differently than the old ones. Re-set sag for your weight.
2. Recheck rebound. New oil and fresh seals can shift damping behavior by 1–2 clicks. The rebound damping guide covers the at-home test.
3. Take a short ride on a familiar trail. The fork should feel noticeably plush in the first 30% of travel compared to before service.

Within 5–10 rides, seals settle into their final state. The fork will feel slightly different on ride 1 than on ride 10, then stable for the next 50 hours.

Common mistakes

• Skipping cleanliness. Any dirt introduced during service will accelerate seal wear. Wipe everything. Clean every tool that touches the inside of the fork.
• Wrong oil volume. Too much oil causes hydraulic ramp-up at full compression, feeling like a hard wall before bottom-out. Too little leaves bushings dry. Measure precisely.
• Wrong oil type. Fox 5wt is not interchangeable with RockShox 0w-30. Use the spec'd oil for your fork.
• Forcing the lowers off. If they will not come off after the bolts are out, you missed something. Check both bolts again.
• Incorrect torque. Under-torque means oil leaks. Over-torque can damage threads. Use a torque wrench for the bottom bolts.

When to take it to a shop

Some situations are not DIY:

• Visible scoring on stanchions.
• Heavily worn bushings.
• Damper service required, not just lower-leg.
• Air-spring rebuild required.

The lower-leg service is forgiving for first-timers. The damper rebuild is not. If the fork feels worse after a lower-leg service, the damper probably needs attention next, and that one is worth shop time. The fork service intervals guide covers what each service does and when each is due.

Where to go from here

After a service, the bike feels different — generally better, but always at least slightly different. Recheck setup. Start with how to set sag, then rebound. If you have not been on top of service intervals before, the warning signs guide is a good reference for catching the next one before it becomes a bigger job.