I assume yours are leaking? Have you checked to see if there is a Zerk fitting for grease at the bottom of the hydraulic cylinder? This greases the seal making for a better seal.
If all else fails, look for a shop that services construction equipment. They usually can service any hydraulic cylinder or point you to a shop that will rebuild it. I found this out from our UPS driver one day. He was delivering a new cylinder to me and asked me why I didn't get my old one rebuilt at XYZ company here in town. I didn't even know it was there!!!!
Good Luck, Be Safe and Above All, Don't Forget To Have Fun
2006 Fleetwood Discovery 35H, 2014 Honda CR-V, M&G Engineering Braking System