Guys,
This subject has probably been covered a few times before but what I'm talking about is the rubber cones on top of the seat back. Those of you who still have them know that they often tend to work themselves loose as the body and frame flexes during use. I'm sure the more experienced guys on here already have their own solutions to keeping them in place but I tried out a method today which seems to do the job nicely. Please note however that this isn't suitable if you plan to fit a high vis mast as the post holes will be sealed up.
First I got myself a couple of M6 x 60mm blind bolts (dome head / stainless), M6 nyloc nuts and 6mm screw-cup washers.
Next up, I used a 6mm drill bit to drill out the plastic obstruction which is half way down inside the plastic 'top hat'.
That allowed me to slide the bolt into place, then fit the washer and nut from below. This clamps the A-frame very securely to the body and also holds the rubber cone firmly in place so it will never be lost. I did consider painting the dome heads black with enamel paint so they match the rubber cones but to be honest I think they look pretty good as plain stainless steel.
This is the view from below.
Usually the body is screwed to the A-frame only by a couple of small screws which are hidden behind the rear light. This isn't very secure so I replaced those with 3mm machine screws, washers & nyloc nuts. Effectively there are now 4 sets of nuts and bolts clamping the body onto the frame and this makes a noticeable difference to the rigidity at the rear of the C5.
Hope this is useful so someone out there...
C.