1st thing I'd do in your shoes is locate (online) the manual. Usually it's in a PDF format for free.
2nd is breakout the tape measure for every concievable detail.
The length overall when fully open & closed. Length of shaft housing with tail connection.
Diameter of hole the bolt goes thru.
Same for other end of Piston.
Hose size and fitting sizes.
All this to compare across other makes & models for patterns and likely swapout or even replacement options.
I've also been surprised at what Merricks can get for my Kelly model #20 backhoe....