We like the Fox Float Air shock. It works well, adjusts easily and is simple to keep clean. Don’t be tempted to go further than the level of servicing below. For that, send it to an authorized service centre or you void the warranty. The damping chamber is charged with pressurized nitrogen, which makes it dangerous to open and impossible to refill without a cylinder of nitrogen.
All types of shocks, both coil and air, are well worth keeping clean and well greased – it costs less to service if you don’t let the internal parts wear out. Most shocks are centrally mounted above the rear wheel. Any mud, grit and sand left over after your back wheel has sprayed a stripe up your back gets dumped onto your shock body. Clean this off regularly; grit will work its way in past any seals, scouring grooves in the central shaft, in turn allowing in more dirt.
This particular shock model allows you to adjust rebounddamping and travel, but other combinations are common on other bikes – preload and rebound is the most useful, although lockouts are great for climbing and roadwork. Some people like to be able to adjust their compression damping. Compression damping affects the speed at which the shock compresses; and rebound damping, the speed at which it springs back.
Greasing air sleeve
If you’re happy with how your shock performs – it soaks up uneven terrain without consistently bottoming out – then measure and record the pressure before you start maintenance, so that you can reinflate to that pressure when the shock is reassembled. It’s also worth checking and noting the rebound settings – count the clicks back to fully open (it’s easy to knock the adjusting wheel during work). As ever, when working with air springs, release all air pressure before starting work.
Step 1: Release air from the shock by removing valve cap and pressing down pin at centre of valve. Pump bike up and down a couple of times through the whole stroke of the shock to expel air from the negative air spring. Release the air at the valve again. Undo the pivot fixing bolts at either end of the shock, usually using an Allen key and socket, or two Allen keys. Pull the aluminium reducers out of each end of the shock and clean them.
Step 2: Clamp the body end of the shock (the end with the air valve and any adjusting knobs or dials) into a vice. Protect the eye bolt with wood – otherwise you damage the shock. Take care not to crush the valve, or the lockout switch, or anything else down there. Stick a screwdriver, or similar, through the top eyelet to stop the air sleeve flying off when unthreaded.
Step 3: Undo the air sleeve by hand. This has a normal thread and undoes anticlockwise. A little gadget called a gator (available from auto shops) can grip the sleeve if stiff, as can the mats that help to remove jam jar lids. Don’t use grips or pliers, which can damage the sleeve. The threads are very fine, so they take ages to unscrew. Persevere until you pull the sleeve free. Remove the screwdriver and pull off the sleeve, along with the travel O-ring.
Step 4: Now the parts have been separated, clean them carefully. If things look fairly clean, just wipe with a clean rag. If things are a mess, you need to clean and degrease (check your degreaser is O-ring-friendly, something like Finish Line Ecotech 2 should be fine). If there’s no grease at all, or the grease is discoloured and dirty, you need to clean-andgrease more frequently.
Step 5: Next, grease. Good-quality, clean grease is essential. I like Pace grease, but there are plenty of alternatives – RockShox Judy Butter is great. There are three sets of O-rings. The two outer sets, at either end of the air sleeve (currently attached to the shock, just below the air sleeve threads), both need a light smear of grease – just a little, but ensure a constant bead all the way around.
Step 6: The same goes for the bearings and seal at the end of the air sleeve. The air sleeve threads also need a smear of grease. Make sure the beads run all the way around with no gaps.
Step 7: Be more generous with the O-ring and bearing in the middle of the shock, the one that sits in the middle inside the air sleeve. Pack an extra layer of grease into the shoulder above the body bearing, which gets dragged onto the bearing and O-ring during the shock cycle.
Step 8: Slide the air sleeve loosely back onto the body of the shock. Air will become trapped in the sleeve, so slide the thin end of a ziptie (not anything metal!) under the seal – see the arrow in the picture, allowing air to escape. Push the air sleeve all the way onto the shaft. Once the threads are engaged, remove the ziptie, then tighten the air sleeve firmly by hand.
Step 9: Refit the travel o-ring. Clean and refit aluminium reducers, with a drop of oil on the outer faces. Apply LocTite to the fixing bolts, then refit the shock to the bike, in its original orientation. Tightening both fixing bolts securely. Inflate the shock to maximum pressure (printed on the shock and in the owner’s manual), then release air to the correct pressure. Refit the valve cap, recheck all nuts and bolts.
Tools for cleaning and greasing air shaft
- Allen keys to remove shock from bike – usually a 5mm or 6mm
- Plenty of good-quality shock grease, such as RockShox Judy Butter or Pace RC7
- Plenty of clean cloth or kitchen towel
- Shock pump to reinflate once you’re done
- Thin zipties
Source : BIKE MAINTENANCE TIPS, TRICKS & TECHNIQUES
See also bike maintenance tips, tricks and techniques “Testing and adjusting rebound damping for the best setting”