Abstract: A valve member (18) can fall down into a cylinder chamber (14) in response to removal of a seating spring (30) from its outer end. This usually makes it necessary to detach the head (26) from the block (12) of an engine in order to perform work at the outer end of the valve member (18). The present invention provides a tool (T) in the form of a tubular body (60) having a nipple (66) at a first end to which a balloon (68) is attached. The balloon (68) and the nipple end (62, 66) of the tool (T) are inserted through a spark plug hole (56) to place the balloon (68) into the cylinder chamber (14). A pump (72) at the opposite end of the tool (T) is used to pump air into the balloon (68), inflating the balloon (68), so that the balloon will exert an outwardly directed force on the head (20) of the valve member (18), urging the valve member (18) towards its seated position. While the valve member (18) is so supported, the seating spring (30) is removed.