Ken,
All new parts and a dressed mating face is certainly a puzzle so is a new component at fault?
<span style=”line-height: 1.5;”>I used to buy water pump seals by the thousand in a previous life. Modern production and quality are good but it is still possible for the odd duff part to get through undetected</span>
If it<span style=”line-height: 1.5;”> does come to stripping the pump out, check the seal for possible manufacturing defects such as splits, cuts or simple poor assembly (I did once come across one missing the spring).</span>
B……