In Reply to: Re: hydraulic issue Ford 600 posted by Jon Calder on December 04, 2019 at 08:06:06:
IMO a modern rubber is a far better choice than leather or metal. People keep saying the backjup ring is neoprene but that has poor chemical resistance to petroleum based products and is commonly reserved for refrigeration system seals. The hydraulic cylinder rubber backup ring is almost surely Buna-N (same as the o-ring) which is far more chemically resistant to petroleum products. PTFE and Viton are more expensive options for both rings with marginal bang for the buck. All of them can be purchased from just about any industrial supply for a fraction of what CNH wants.