Pedal problem

[gnomino]

> not top-posting

Hello,

I'm trying to typeset two staves with different rhythms and pedalling that
starts/stops on the notes in the top staff, but appears below the second staff.
I tried the following:

\new PianoStaff <<
        \new Staff {
                c'4 c'4 c'4 c'4
        }
        \new Staff <<
                \set Staff.pedalSustainStyle = #'bracket
                \times 4/6 { c'4 c'4 c'4 c'4 c'4 c'4 }
                { s4\sustainOn s4\sustainOff\sustainOn s4\sustainOff\sustainOn
s4\sustainOff\sustainOn }
        >>
>>

However, the pedal bracket appears disjointed and uneven. Is there any way I can
fix this?

(I'm using 2.13.0)

Thanks in advance.