Hydratech Hydroboost Problem(?)

[Brass]

Hi all,

I am hoping to pinpoint what is going on with my brakes.  Under hard braking, the car is making a severe grinding noise.  (Almost like ABS behaves but more grinding, no pulsating.)  It seems to be getting progressive but normal braking is still fine.  The front discs, EBC pads, and bearings have less than a couple seasons on them.  The rear drums are also in great shape.  If the engine is shut off during hard braking, the noise does not happen.  One time the car started to shutter while pulling into a tight space, at full steering lock.

I enlisted the help of a professional shop and replaced the power steering pump but the problem persists.  Could it be the hydroboost itself or the MC?  I suppose it could be the steering box but that seems less likely.  The pump was a reasonable gamble but I prefer to avoid replacing parts without knowing what's really going on.  Has anyone with hydroboost experienced this problem?  Could it actually be normal?  The shop also reports a whoosing sound when they try to recreate the symptoms.

The unit came from RMS and Bill helpfully offered to speak with Hydratech on my behalf.  Discussions are still ongoing but no actionable insight yet.  So I thought it wouldn't hurt to open this up for input.    

Ideas and suggestions would be welcome and appreciated – thanks!