Cool truck
You would have v packing or chevron packing in those cylinders you could try to snug the bolts on the gland ring a bit that would squeeze the packing and make it tighter to the ram but if its gushing its probably to far gone You would have to dissemble and get one of those cheap calipers to match up measurements
https://herculesus.com/product.php?name=Vee Packing Sets&cat=15538
https://www.goodyearrubberproducts....d_Sealing/files/assets/downloads/page0175.pdf