I've got the Lansdowne dampers, I don't believe I used any torque value when I put them together, just the usual feel that I use every day. What I do use is a coding of Loctite 518 on both sides of the fiber washer when assembling it to make sure it seals. Yama Bond number four also Works same as three bond 1184. I've been doing this for 45 years, never ever had a leak. I also use it where aluminum washers are employed such as on a Japanese bike. You may wish to consider renewing the sealing washer.