2010 F90/F100 Fork Air Spring Quick Service

Note:  In the 2010 product going forward, the air spring is serviceable only from the lower end of the left leg. The reason for this is the butted nature of the 2010 fork tubes; the inner diameter of the upper tube is smaller at the fork crown than it is at the bottom.

This procedure begins at the point where the lowers have already been removed.

Disassembly

1. Remove the air cap and depress the Schrader valve to release the air pressure out of the fork.
   
   
2. Tilt the fork to the horizontal position, to remove the first cir-clip at the bottom end of the air side leg.
   
   
3. Next, remove the negative spring plate. Note the groove around the inside edge of the plate; this groove must be facing the inside of the leg when it's installed.
   
   
4. Next, remove the inside cir-clip.
   
   
5. Pull and slide the air shaft assembly out of the fork leg.
   
   

   Note:  At this point, you have options as to how to service the air shaft assembly, whether it's replacing the piston o-rings, the piston, the entire assembly, or adjusting the ride height. The focus of this procedure is the quick disassembly and re-assembly of the air shaft assembly from the bottom end of the left fork upper tube.

   For more information about changing travel in 2010 32 mm FLOAT and F-Series forks, see the "2002-2012 & 2013 80 - 120 FLOAT/F-Series Travel Adjust" service procedure.

Re-assembly

1. After completing any necessary service work with the air shaft assembly, coat the air piston with some FLOAT fluid.
   
    
2. Re-insert the air shaft assembly back into the left fork leg, from the bottom.
   
    
3. Release the trapped air as you push the air shaft assembly up into the fork leg.
   
   
4. Install the inner cir-clip.
   
   
5. Install the cup with the grooved edge side facing inside.
   
   
6. After securing the outer cir-clip ring into place, give the shaft a good tug, to ensure that it's well seated.
   
   
7. Remove the topcap assembly.
   
   
8. Pour in 5 cc of FLOAT fluid.
   
   
9. Reinstall the topcap.
   
   
10. Tighten the topcap to 220 in-lb torque.
    
    
11. Pump in ~10-15 lbs of air.
    
    
12. Install the lower leg assembly.
    
    
13. Remove the fork assembly from the work stand and hold it, steering tube down, on the floor. Fill each fork leg from the bottom with 30 cc of 10 wt. oil.
    
    
14. With the fork still upside down on the floor, press the lower assembly downward. Use a pick tool to help guide the threaded end of the air shaft assembly through its corresponding hole in the lower leg.
    
    
15. Place new crush washers on each side.
    
    
16. Thread on the nuts.
    
    
17. Tighten each nut to 50 in-lb torque.
    
    
18. Finally, re-install the rebound adjuster knob. Be sure the set screw seats correctly into the divot in the adjuster shaft.
    
    

use proper tools, supplies & kits · read all warnings · know oil volumes and inspection guidelines · know disc brake specifics for all Fox forks · know air shaft travel specifics for FLOAT and F-Series forks · use correct fork torque specifications