Hello, I am reasonably new to hydraulics and maintaining my excavator, so please forgive my ignorance. I have a 2003 Deere 120C and I have a small leak on the right side of the thumb hydraulic cylinder. I have attached a picture of where the leak is coming from. I believe the fitting size is a "12", based on what the fittings at the end of the hose says. I am not sure if this assumption makes sense The leak is coming from the threaded area of the 90 degree fitting. The 90 degree fitting seems to be in there really tight. I am hoping that if I disconnect the hydraulic hose and take the fitting off that there is an o-ring inside that I can replace. Many of the fittings on that side of the stick/boom are flat-face style with an o-ring. Though, I don't have any fittings where there is a male that screws into a female side. Does anyone have any idea of what I should expect when I take the 90 degree fitting out? Any ideas would be helpful! Thanks, Chris
Yep, you've got it. These is an O ring under the nut. Take the hose off, loosen the nut that your arrow is pointing to and then unscrew the elbow.
If it's an 1 1/4 nut it will be a 912 Oring
Make sure the thumb is supported against something and can't fall and that the cap on the hydraulic oil reservoir opened so there is no pressure there. You wouldn't want to inflame any of the greenies down there by letting a drop of that nasty chemical touch the ground