The duct from the pressure reservoir to the shock absorber is often heavily rusted. In addition, the cap screw at the junction of the duct and the hydraulic hose can not be loosen in > 95% of the cases, because the cap screw is rusted permanently with the duct.
First-hand we can report that even several days attemps with rust removers and heat rarely lead to success :(
A repair of this component is not possible, we recommend the replacement before the line breaks and the hydraulic fluid leaks under pressure.
The heavily corroded hexagon socket banjo bolts at the connecting of the duct and the pressure reservoir are difficult to loose, we recommend the replacement with the solid hexagonal banjo bolt hs-m16 and with new washers al-m16.