Timing belt change on 2006 Aveo LS: My new detailed write-up

[avguy]

I can't imagine anything other than one or more of the WP bolts being capable of holding the pump on through all the stuff you're doing. Did you remove all 3 of the 5MM allen bolts? If so, the only other possibility is for the pump to be somehow rusted into the block. But, I can't imaging that being able to withstand hammer blows, without breaking up the corrosion. Edit: after posting I read Rabbit's reply - never occurred to me, but 16 psi might be enough to hold it in!