Hi Jon     I have repaired many Hobart 403's   but  they're not easy   Usually when the blade roller assembly needs replacing it is because several of the knife blades are bent or mangled   If this is the case , possibly both front and back roller assemblies need replacement   also check the strippers they could be bent as well.  Then check the hanger or housing  if there are any cracks  or it looks weak   don't use it  it can cause more damage 

  Changing out a roller assembly is not always successful  there are alot of small parts that haven't been apart for a long time and sometimes they break or cannot be reused to complete the repairs  then you're stuck.   If you have more than one damaged piece I would always recommend replacing the entire unit , complete  2 rollers , 2 strippers and the hanger assembly.  It is already aligned so all you have to do is put it in.  Complete units run around $ 750  but they save you time and aggravation, if not money.

   All that being said, if you still want to go on, this is how you do it.  First remove the set screw 14 or 19  it's in there under the silicone  it's small and gets rounded out sometimes   Next remove the set screw on the other end 3 or 27 then carefully try and remove the left brass bearing 2 or 28  use alot of penetrating oil here as this is where the housing cracks  Once removed you should now have enough room to slide out the roller and the right side brass bearing replace the roller and reverse the process but DO NOT tighten the set screws yet  First check that the rollers and strippers do not touch each other and spin freely  make sure the front and back rollers do not touch  do this by hand  if they touch and you turn the cuber on you could do damage   then tighten set screws to lock in place  then CHECK AGAIN !  adjust until perfect.   Hope this helped. GOOD LUCK.   BANDSAW BOB      If anyone has any equiptment repair questions drop me a line here at MCC or at info@bandsawbob.com