There is oil leak so I purchase used rear shock for replacement. But I have no idea which side of hydraulic pipe has to be disconnect ? I suppose I must also bleed preload system after installation, how ?
Show must go on so I made my own decisions and opened pipe connection from banjo bolt connection side and changed rear shock to new one. I tried also bleed system with my DIY adapter: I drilled 1.5mm hole to M5 stainless steel bolt and superglued (with activator) injection needle to it. First tried with syringe but changed it to vacuum pump which is from my (chinese made) brake bleeding kit. I am not sure if system is totally without air but it works fine. Only not so perfect working detail is when preload goes zero position servo motor rotates few seconds before it stops. Also when I set Enduro mode it takes about two seconds servo rotation before preload ring starts to move. So there could be some air still in system but I suppose I need get real vacuum pump to get rid of it....
Finally succeeded with bleeding with syringe. Now servo stops immediately on both ends and preload ring movement is fully extended in Enduro set up Used Motul 7100 10W40 as oil, not sure which viscosity is right one, but it works well.
7100 is an engine oil not an hydraulic oil. That might come back to bite you. I would have expected to use a 5 or 7.5 weight hydraulic oil. Andy
In my latest information the OEM oil which is used by Öhlins for this kind of preload system is their fork oil type 1309. https://www.wrs.it/en/fork-oil/27960-ohlins-fork-oil-r-t-1309-1-liter.html Viscosity - 19 cST at 40°C Motul 7100 10W40 is ester based motor oil, thicker with different additives but few millilitres in low speed moving hydraulic cylinder system... not my kind of thing to get worried about.
