Operating instructions

18
NH NK NL NX FM VEHICLE BEARINGS
(1) Select a suitable horizontal location for the roof bearing. Maximum and minimum
installation dimensions are shown on pages 16 and 17.
(2) Cut a hole in the outer skin equal to the internal diameter of the bearing tapping
plate.
(3) Clamp the outer flange centrally over the hole and using as a template, drill six
holes 6.5mm diameter (8 holes for NY series)
(4) Assemble bearing as shown in drawing, with the neoprene gasket sandwiched
between the outer flange and the vehicle skin. The screw head should be sealed
with a suitable compound to prevent water ingress. If the roof is not perfectly flat,
it may be necessary to use sealer at this location also.
(5) Remove inlet valve from base of mast with box spanner provided.
(6) Fit the neoprene O ring over the base of the mast and position at the approximate
height of the bearing. Ensure that the PTFE ring is fitted in the flange. The mast
may now be lowered through it. It may be necessary to shave a thin layer of the
PTFE with a sharp knife to ensure good fit. If the mast is to be rotated in normal
use, leave a minimum gap between the mast and the Teflon, since excessive
clearance at this point will lead to considerable wind noise when the vehicle is
travelling.
(7) The lower end of the mast can now be fitted into the base plate secured directly
below the roof bearing (tighten the two M6 screws in the base plate).
(8) The two halves of the roof-bearing shroud may now be clamped into position.
Lightly grease the outside of the O-ring and make sure that it lines up with the
groove in the shroud. The mating faces of the two halves of the shroud should be
covered with sealing compound before clamping securely to the bolts. Vertical
clearance between the shroud and outer flange should be just enough to allow
the mast to rotate without any parts rubbing. If mast rotation in service, is not
required to use sealing compound inside the shroud before bolting up.