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Necessity of Overhaul

A damper consists of nondurable components. Tens of thousands strokes per 100 kilometer drive generate and radiate heat constantly. Oil is degraded by this heat, and sealing is also degraded because of continuous friction. This oil and sealant degradation is invisible, but it has great effect on the driving condition such as unstable handling, unwanted noise, etc. that is very dangerous and uncomfortable for a driver. Therefore, overhaul at a regular interval is necessary to maintain the original performance.

When to Overhaul?

  • A vehicle moves unsteadily when changing lanes on a highway.
  • Excessive nose dive occurs when applying the brake.
  • Steering response becomes slower.
  • Rattling noise occurs.
  • Oil is leaking.

Overhaul your damper when these or similar symptoms are noticed.

Replacement Parts for Overhaul.

  • Sealant such as a gas seal, oil seal, dust seal, etc.
  • Oil
  • Gas
  • Rod(s), valve(s), and other components that are damaged.
Overhaul service is available for all HIPERMAX series.
* Except for HIPERMAX G

Services of overhaul and damping force adjustment are available after purchase of the Hipermax series.


  • Contact an HKS dealer for overhaul.
  • The overhaul fee may vary depending on the damper's conditions. Additional fee may be applied.
  • Only internal parts are replaced.
  • Overhaul must be done on both right and left dampers together. If not, the unbalanced damper setting will adversely affect the performance of the vehicle.
  • Overhaul and spare parts are not available for the products which have been out of production for more than 3 years.
Expiration of Overhaul service


  • 1. Disassemble the damper.

  • 2. Disassemble all components.

  • 3. For the inverted type, the inside of the outer case is examined and cleaned when any rust and/or dust is present.

  • 4. Right: Oil drained from the damper. The oil was degraded and discolored by heat.
    Left: New oil. Its color is clear.

  • 5. The piston and valve are disassembled into pieces.

  • 6. Disassembled components are cleaned in the cleansing booth.

  • 7. The valve is cleaned piece by piece carefully.

  • 8. Each nondurable component is replaced with a new one. The damper is reassembled.
  • 9. Rubber components of a dust seal and other parts are replaced due to being degraded over the years of use.
    Right: Degraded part
    Left: Replacement part.

  • 10. While reassembling the damper, oil must be constantly poured over the gap between the components to prevent air from entering gaps between them.

  • 11. After assembling is completed, the dampening force test is conducted.

Basic Charge of Overhaul and Dampening Force Adjustment (per damper)

  Normal Type Inverted Type
Code No. Code No.
Overhaul 1. Disassembly, Reassembly 82003-AK009 82003-AK010
2. Nondurable Parts Replacement 82003-AK011 82003-AK011
Dampening Force Adjustment 3. Rebound Side 1790-SA004 1790-SA004
4. Compression Side 1790-SA005 1790-SA005
Only Overhaul 1+2    
Overhaul + Dampening Force Change 1+2+3+4    

* Make sure the removed parts are in storage.