If you have an hydraulic power system that has a damaged cylinder, you have to hire a competent service provider to either replace it or carry out repairs. It is important to note that most problems affecting hydraulic cylinders can be fixed by a qualified professional. This is a mechanical engineer that has specialized in hydraulic systems, not your car mechanic. Since there are many hydraulic engineers in every major city, you will need to search the web for local engineers and shortlist the most reputable ones.
Obviously, you want guarantees, so you should only give consideration to experienced service providers with a valid insurance policy and license to offer hydraulic cylinder repair services. The ideal firm should charge competitive rates for repairs and offer a customer satisfaction guarantee. In case a component has to be replaced, the ideal firm should offer a warranty on that part as well as the repair service.