HEIR Fork Service Guide
This is a simple procedure for most skilled home mechanics, but it does require some specialty tools. Some of these tools can be substituted, but be very cautious on the wrench flats since most of the hardware on this fork is soft aluminum. If you do not have the correct tools, I would recommend taking the fork to your local bike shop.
- Metric Allen Key set
- Socket wrench
- 27mm flat face 6 point socket
- 9mm deep socket
- Park Tool SPA-2 spanner
- Park Tool TL5 metal tire lever
- 30mm dust wiper press
- Dental pick
- Shock Pump
- Torque Wrench
- Slick Honey grease(or equivalent)
- Lint free shop rags
1. Remove fork from bike, and clamp in repair stand.
2. Let the air out! Remove the air cap, and press the center of the Schrader valve until all air is removed from fork.
3. Remove lowers:
- Remove the red rebound knob by loosening the small 1.5mm allen screw on the side of the knob. The screw does not need to be removed, only loosened enough for the know to slide off.
- Under the knob is a bolt, remove the bolt using a 9mm deep socket.
- On the opposite fork leg, remove the bolt with the same 9mm socket.
- At this point you should be able to pull the lowers free.
- If the lowers do not pull off: Thread the bolts back in 3-4 turns. Place the socket over the nuts and gently tap the socket with a hammer until you feel them push free. Remove the bolts and the lowers should now slide off.
4. Air shaft
- Remove the air shaft by turning the retaining nut counter-clockwise with your Park Tool SPA-2
- There might still be a small piston in the air chamber. If you add a little bit of air to the fork, it will shoot out.
- Thoroughly clean and re-grease air shaft/negative spring.
- Use your dental pick to remove the o-ring from the black piston. Grease the new matching o-ring from your service kit, and reinstall it.
- Sit piston on top of air shaft, and gently slide the entire assembly back into fork leg. Tighten retaining nut with SPA-2. Note: Air pressure will build as you insert the air shaft, either relieve pressure by pressing in the center of the air valve OR remove the air valve now since it's the next step.
5. Air Side Top Cap.
- Use your 9mm deep socket to unscrew the air valve. This is getting replaced, so you can throw the old valve away. Tighten in the new valve from your kit to 8nm.
- Using your 27mm flat face socket, remove the top cap.
- Remove the o-ring from your air cap with your dental pick. Grease the new matching o-ring from your service kit, and reinstall the top cap. Torque to 20nm.
6. Damper Side (Skip this step unless you are replacing damper)
- Use a 2mm allen key to remove lockout knob(There is a very small ball bearing under the cap, do not drop it!) Remove the small spring that was under the bearing. Set cap, screw, spring, and ball bearing aside.
- Use 27mm flat socket to remove damper.
- Reinstall new damper, torque to 20nm.
- Set spring & ball bearing into the same position they used to be in.
- Install top cap, and check operation.
7. Dust Wipers
- Use your metal tire levers to pry the dust wipers out of the lowers.
- Thoroughly clean inside of lowers with a clean lint-free rag.
- Grease surface of new dust wipers, and press into lowers with your dust wiper press.
8. Install Lowers
- Apply a liberal amount of slick honey to the inside of the dust wiper on the lowers.
- Gently slide the lowers onto the stanchion tubes. You will need to wiggle the lowers a bit to get the dust wipers over the tubes.
- Replace crush washers and o-rings on the retaining bolts for the lowers.
Assembled nuts should look like:
- Make sure to install the Damper side nut on the right side(Lockout side) and the Air side nut on the left side with the Air cap.
- Torque nuts to 12nm
- Install rebound knob. Note: there is a small hole in the shaft of the damper bolt, and that shaft needs to align with the dimple on the secondary internal shaft. If your rebound knob spins forever without a stop, you missed the dimple.
That's it! Time to air up your fork and put it back on the bike!