Vehicle drum brake adjustment mechanism - adjustment cylinder with mutually opposed pistons and grease lubricating system

摘要

A brake adjustment mechanism to avoid salt and mud encrustation and corrosion has a fixed backing plate (11) and a pair of moving shoes with adjustment mechanism. There is an adjustment cylinder at the opposite end to the slave cylinder (32) which is fixed to the backing plate and there are a pair of adjustment piston(s) (51). There is apart in the centre of the cylinder at the rear face of the two pistons with a valve and lubricating nipple. Grease can therefore be forced into the zone between the pistons. The valve (34) has a conical face and seating (44). The latter being formed in a sleeve (35) that is screwed into the port (46). The two ends of the shoes are held against the adjustment pistons by a spring (56). The inner ends of the pistons are spherical.