Give them a ring they may be easier than mine which have to be taken out unless the adjuster can be accessed in situ.
On mine ( Lunar Solar C/van0 is a plastic collar that sticks out from the roller case. Place screwdriver in slot on end of collar push in turn to tension, usually clockwise. Release slow to ensure your inline with the stop and the collar comes back out to engage in the stop.
Avondale Coachcraft Ltd
Carlyon Lane
Atherstone
Warwickshire. CV9 1JE Tel: 01827 720 500
Fax: 01827 716446
Avondale Caravan Specs
bob
May 2012