 My Sienna CE and have had an on going 
problem with the rear brake drums.  The 
rear brakes have a thumping sound under 
low speed braking. There is little 
point to machine the rear brake drums, 
since this remedy does not work. Toyota 
has not been able to repair the rear 
brakes because of &#8220;hot spots or hard 
spots&#8221; in the drums.  The turning of 
the drums is only a temporary solution 
and has the brake wear the &#8220;harden 
spots&#8221; become high spots that cause the 
thumping noise to occur.