Hello, I'm changing the seals in an idler tensioner on a mini-x. So it's essentially a single acting cylinder. My understanding says the backup ring goes on the zero pressure side of the rod o-ring. The parts diagram from komatsu shows the opposite. I just wanted to check my assumption is correct and the diagram is wrong. #13 is the rod o-ring, #14 is the backup ring.
And when you took the old ones out how were they all arranged?
Is seal #12 keeping something in or out ? If it's a dust seal manual is correct. Joe H
The manual is correct
It all got mangled up and melted, I put a torch to it to help free up the spacer (#10). #12 is the wiper dust seal. I guess my understanding of it is wrong if the manual is correct. Can anyone explain what the backup ring does exactly? My understanding is the backup ring provides support to the oring to prevent it from being extruded into the gap between the rod and gland. As grease is pumped into the cylinder, pressure it going to be pushing the oring towards the gland. Hence, I thought the backup ring should be on the gland side of the oring instead of on the cylinder side. Also, the wiper seal #12 is not touching the oring #13. There is a separate groove in the gland for the oring and backup ring.