Öhlins O-ring 78x2The facts.
| Brand | Öhlins |
|---|---|
| Part Number | 00638-21 |
| Category | O-Rings |
| Inner Diameter | 78 mm |
| Cross Section | 2 mm |
| Country of Origin | Sweden |
DescriptionThe whole story▼
O-ring 78x2, Öhlins part number 00638-21. Dust seals keep grit off the running surface; once they are torn, the oil seal behind them has a short life.
Key Features
- Inner Diameter 78 mm
- Öhlins part number 00638-21
- Cross Section 2 mm
- Original Öhlins service part
Where It Sits
00638-21 is the 78 mm, 2 mm version — Öhlins lists each size separately. Öhlins uses seals with a spring-loaded lip so they follow the shaft as it wears. O-rings are single-use in a pressurised damper — they are replaced whenever the unit is opened. Dust seals keep grit off the running surface; once they are torn, the oil seal behind them has a short life.
Original Öhlins Part
Öhlins lists this part under its own number in the service catalogue so a workshop can order exactly what it needs. Öhlins keeps service parts available for units long after they leave the current price list. The Öhlins exploded view names the number for each position; we can look it up if you do not have it. We can check the number against the Öhlins exploded view before you order — just ask.
Getting the Number Right
If the unit is already open, compare the dimensions below with the part in your hand before ordering 00638-21. The published dimensions are inner diameter 78 mm, cross section 2 mm — measure the old part against them if you are unsure. O-ring sizes are given as inner diameter and cross-section, and both have to match — a close size is not a match. Öhlins recommends replacing seals whenever the unit is opened, not only when it leaks.
Fitting and Setup Service
A damper rebuild is workshop work: it needs the unit dismantled, the shim stack rebuilt in the correct order and the gas charge reset. We are an authorised Öhlins service centre and do exactly that in house — send us the unit or ask us to fit the part with your order.
Specifications
- Brand: Öhlins
- Part Number: 00638-21
- Category: O-Rings
- Inner Diameter: 78 mm
- Cross Section: 2 mm
- Country of Origin: Sweden
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