Felicia Steering fluid spraying out

hello all.

my kids 1.9d felicia has no steering fluid in the reservoir.

if you fill it up and leave the cap off, start the engine the fluid gets sprayed out everywhere.

if you put the cap on it waits till pressure builds up then sprays it everywhere.

to me its a valve or something. but i have no clues where to start.

can anyone give me a direction to go. apart from the pub.

thanks in advance