Rear Camshaft pulley is bouncing back, should I push through
2006
Toyota - Sienna
Engine - 3MZ-FE
Quick n' Dirty Summary -
The rear crankshaft pulley keeps jumping back each time I attempt to bring it to the TDC position, and I don't know if I need to push through some spring resistance or if that will be me ramming the valves into the piston heads.
Longer explanation-
My water pump had started to lose control of it's bladder, leading to it leaking all the time, and needing to be replaced. After looking up different guides and printing off some references, I was off to the races.
The point I believe things first started going wrong was when I followed the guide's suggestion to rotate the crankshaft pulley CW until all the pulleys registered at their TDC mark, and then rotate the crankshaft CCW 60 degrees before removing the timing belt. After removing the belt tensioner, that gave the belt a decent amount of slack. That's when the rear camshaft pulley first sprung back away from its previously aligned TDC mark.
I first finished replacing the water pump before I finally got back to attempting to bringing everything back to TDC to put the new belt on. The rear pulley was the last to be brought to its TDC position and started giving enough springback that I felt uncomfortable applying any more force in case the valves were impacting the piston. After rotating the crankshaft CCW back by 30ish degrees in case that was the issue it still had the exact same problem. I don't feel any excessive resistance or springback from either the crankshaft or front camshaft pulley, so I am at a loss.
I am moving the pulley only a small amount in the gif to give the general idea.
Any recommendations would be incredibly appreciated.