Volvo Repair: Brake shudder on 850R wagon, linnings, rear brakes

Question
My 1996 850R has developed a severe shudder under light breaking to a stop,as opposed to "no" shudder under hard braking. I have now had the entire front n rear brakes/rotars,calipers and linnings replaced.
The Tyres have been changed/balanced n alinged
This seems to even have the mechanics unable to fix .
Do you have any suggestions ?
Thanks in advance

Answer
the only thing I can think of like this is a loud ressonating type vibration on this type of braking.which happens if you are using volvo pads that are a later pad found on a S70 model which do fit this model and is OK to use however if you use this pad you need to install the shims which are a half cut shim and not a full shim.there is a bulletin on this.