I took my 85 Vanagon with 220,000 miles in to have Front Wheel Bearings repacked, Rear Wheel Bearings repacked (inspection revealed all bearings in good shape, no replacement), brake fluid flushed.  Mechanic did those; he also noticed about 1/8" play on the left Tie Rod bushing, the right side had no play, so got the left Tie Rod bushing replaced.
As I drove off, I sensed a slight "shudder" when lightly applying brakes at low speed, maybe 20 MPH.  The sensation was like driving over washboard road surface, in fact that's what I thought it was.  But as I drove further and started testing different brake pressure at different speeds, the shudder was reproducible.  Again...always with a light touch on the brakes and at low speed like coming to stop.
Took it back to mechanic.  He thought at first warped rotors.  But the problem wasn't there before the bearing re-packing.  He drove it....and was dumbfounded.....said he'd never seen anything like this before.  And the shuddering appears to be getting worse.  

We are stumped.  Any ideas?

RichSan Diego