I sent an email to Peter B, Director of SSL and received a timely response. He is not permitted to post on TM for commercial reasons, but has given me permission to share his response. I am happy and relieved to say that he affirms that the installation instructions are correct and has given reasons why. This all makes good engineering sense to me and is the way I have always fitted mine. I cannot see why any type of shock absorber would warrant a different approach as the forces and stresses would be similar as the suspension moves. Being over tight on the top cannot do the damper plate any good either.
Anyway, here is his reply: (hoping I am not breaking any TM rules by posting!)
Douglas, thanks for the email, the SSL RS instructions are correct.
The bottom nut indeed tightens against a step so should be tight against that.
The top nut must be just tight enough so one is able to just turn the top washer or rubber bush.
There are reasons for this:
#1 As the steering turns the damper axis moves in a conical path and so pivots on the top damper plate. If the rubbers are too tight then the damper rod twists the damper plate so potentially reducing the life of the damper plate that are not that robust anyway.
#2 If the top rubbers are tight then turning the steering puts bending into the damper thus increasing the wear rate in the rod bearing/seal and the piston/bore thus potentially causing leaks and loss of damping sooner than expected. SSL follows advice from SPAX.
#3 Leaving the rubber bush under the top plate uncompressed means that it is able to deform a little to reduce road induced harshness coming through the damper to the chassis.
NB We have used an axial self lubricating bearing instead of the lower rubber bush on the damper rod on some of the race cars, also on my Morgan. As image attached.
PS Despite being a Morgan owner I am not allowed to post on TalkMorgan as I am commercial. I have asked to be allowed to post again, but no longer get replies.
Hope this helps, if you wish to post this or summarise then that is fine by me, thanks.
I understand PB's warning on fitting the SSL RS kit with Spax gas assisted shocks, particularly as I've had both shock upper mount plates break! However I disagree that the top mount nut should be left other than bolted up tight against the metal spacer as intended, particularly given experience of the OP of this thread.
To this end I disassembled upper mounts and made some measurements. The spacers are 12mm o/d x 10mm i/d and 32.2mm long. I obtained some matching stainless tubing (from
here) and cut fresh ones 1mm longer. This I determined would leave minimal pre-load on the two upper mount rubbers that sandwich the mount plate, and so match PB's instructions. I re-assembled with red rubber grease (thanks Cooperman) using fresh stainless nylock nuts. Note the latter are fine thread M10 x 1mm pitch and available
here. The rubbers can now just be turned by hand when steering in straight ahead position but will always tighten up on full lock due to the conical twisting that PB mentions.
