DS21 & DS21M / DS19A & DS19MA Repair Manual — Page 217

8/w/37 DISMANTLING. 1, Remove the pipe assemblies. 2. Compress the piston return springs of the gear- change control, (the use of pliers 3171-T will save time). After compressing the spring, hold the piston in this position by means of a screw (A) 4mm diameter x 0.75 mm, length under head 40 mm (plain washer under head). If this tool is not available, use a screw (B) 4mm diameter x 0.75 mm, length under head 80 mm, with a nut and a plain washer.