I have a set of Struts that (one) developed a leak at the top seal, considering there is only one lip seal and two O rings inside them, I simply wanted replace the seals/O rings and replenish the oil. The mfg didn’t/wouldn’t tell me the visc only stated to use 50wgt if I wanted to stiffen them up until I can send them in for service. Well its $300/strut to install $10 in seals and O rings and oil in struts that are working fine otherwise. I don’t want to stiffen them up so I guess I'll have to do some comparative analysis, at least I know it’s less than 50 wgt…
Go to a Motorcycle place, they sell all kinds of shock oils