复数： backrests

Install upper part of lock for backrest adjustment .

安装靠背调整装置的锁的上部。

When removing the backrest , the bearing sleeve may come loose and catch on the pin .

拆卸靠背时，轴承套筒可能会松动以致挂在销上。

Remove motor for backrest adjustment .

拆下靠背调整电机。

Insert backrest motor from below .

将靠背电机从下面插入。

Release backrest and tilt forwards .

释放靠背并向前倾斜。