my water pump pulley keeps cracking out on my 1966 mustang, its a 289 engine, cracks around the mounting bolts, i have had pulleys lazer aligned , have stamped steel pulleys, what could be causing this?? need help thanks

 

Have you replaced the water pump yet ?

 

have not replaced water pump, new engine build, about 1800 miles on engine and pump

 

Lazer aligned? Never heard of that but the world is full of things I have never heard of.


First thing I would check is to make sure you have a matching set of pulleys and brackets. 1969 and prior or 1970 and later. Make sure you have a matched set because you can drive yourself nuts mixing and matching pulley and bracket parts from different eras. Also verify that your water pump snout is the correct length.

You said that it keeps cracking which leads me to believe that this isn't the first pulley to do this. That tells me that you have some serious stress pulling the wrong way on that pulley.