- REP Wiper seals are typically used on hydraulic and pneumatic cylinders, as well as telescopic suspension forks for motorcycles and bicycles. Wiper Seals are available in several styles to keep contaminants from entering the cylinder. Besides direct wear to the rod seal, external contamination, if allowed to enter a hydraulic system, can have disastrous consequences. Contaminated hydraulic fluid can quickly wear out seals, clog filters, and damage machined surfaces