I had a similar problem with my 2000 model Allegro. In other posts there was discussion of the center bolt/nut coming loose. I found a PDF file catalog from DENSO.
DENSO Downloads
The wiper catalog has detail drawings of several years/models of motorhome wiper systems. I don't see a drawing for a 2005 Allegro Bay, but it may be close. For my motorhome, the loose nut was part #12 in the drawing (for Allegro). I loosened the bolt/nut assembly completely, reset the position of the wipers and tightened the nut. Still working great. Hope this can maybe help you.