I have a 1957 Case Industrial wheel tractor with a 310 backhoe. Have the originial parts manuals for the 310 and 320 backhoe units.Cylinders are of the tie rod type and hydraulic boom cylinder, oem number 36070, seals at both ends of the cylinder. Rear seals ,packing type, case number: 30568 and wiper seal case no. 30574. seal for rear of cylinder is 49381 which is a seal o ring cylinder tube. packing piston: case no. 17578 and an A7623 seal o ring used with piston D23736 part numbers for the 320 backhoe unit. parts mostly identical on the 310 backhoe unit.