brake change over

[mustang429]

ok guys a friend of my put cobra front brakes on his 01 gt now his not getting a soild pedal his doing a complete change over front and rear what up with the it dose he need a different proportional valve any help please thx

[5.0calypso93lx]

Is this a hydraboost car?

[mustang429]

i dont know he just called me for help stock gt would that mess it up