Hissing of air in front

[Bob Lawrence]

Hi group,
One of our PNW bird guys has a air hissing problem. It seems that when
he pushes in the emergency valve, a black hose on the drivers side that
hangs down hisses air. When the valve is pulled, the air leak stops.
What can I tell him that might be the cause?
He has an 87 PT40.
Also he has been told his HWH pump is shot and will cost approx 4k to
make a new one (per his conversation with HWH). Any other source for
this? He wants to get new if possible.
Thanks for your help.

Bob Lawrence
84 PT36
Tacoma, Wa.