ABS/Booster noise

I've got a 2009 TRD Tacoma and I'm having a squealing noise coming from the master cylinder/brake booster. After I start the truck I hear this sound about every 5 to 6 seconds and last for 1 second. I can see the hose that goes from the abs motor collapse on itself when it makes the sound. Any ideas?

 

So out of curiosity I replaced the hose just to see if that helped and it actually did. Drove the truck around for 30 minutes with no noise until I went into a sharp curve and the VSC kicked in and then the noise started back. Went home put the old hose back on and the noise went away???

 

pic of the hose you are replacing?

 

This is the hose I put on temporarily(where you see the hose clamps), I put the factory one back on.

 

Okay, so I'm not finding much info on the web about this but I've been doing some work. Just to make sure everything was good I went to bleed the brakes and I have no fluid at the rear axle. I have also read of a similar incident and the guy said he cleaned out the accumulator. I've called Toyota and they are stumped also, anyone have any ideas?

 

The problem seems to be it's not getting enough fluid out of the pump/accumulator