You've got to assume that, because of the age of the shock and the fact you are having to replace the spring, that the damping side of the shock will be just as bad (the Sachs damping isn't great to start with).

Owners had successful results adding a Hyperpro spring to nearly new shock bodies in the first few years of ownership but not so much on older, higher mileage bikes. I'd be considering a replacement aftermarket shock.

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