3-Point Hitch MF 135: Replacing hydraulic cylinder piston (rings)

[klancf51]

I'd like to replace the hydraulic cylinder piston rings. Is it possible to remove the hydraulic cylinder piston without first removing the hydraulic cylinder?

 

[Jerry/MT]

Probably not. My guess the "dog bone" that pushes against the rockshaft needs to be removed to get the piston out. Generally it's a big job to remove the rockshaft. Just four bolts remove the cylinder

 

[klancf51]

I am providing the answer to my question: the hydraulic piston can be removed & replaced without first removing the hydraulic cylinder.

1. Remove the two set screws attaching the connecting rod ("dog bone") to the ram arm.
2. Remove the connecting rod.
3. Remove the piston (I used compressed air applied to the standpipe - without pressurizing the cylinder, withdrawing the piston is difficult).
4. Check the chamfer on the cylinder and make sure there are no nicks or burrs. Mine was chamferred.
5. Install the pistion & rings using a piston ring compressor about the same height as the piston. Long piston ring compressors will not fit between the cylinder and the ram arm.

The piston & rings were Sparex 41358 (equivalent to MF 1665737M91) which has a PTFE (Teflon) seal.