HELP broken water pump shaft

[trx250scar]

so i have been having issues with my 330 overheating since day one. talked with eddie at esr and gave me a few things to check/try. one of them was to make sure the impeller had the small washer behind it. i checked it did. started reassembling and some how broke the shaft when torquing the impeller nut back down. i dont understand how i ,had the damn torque wrench on 8 ft lbs. any suggestions so if and when i get a new shaft i dont do it again? i am nearly thru dealing with this damn R. if someone could help me out it would be greatly appreciated. i am almost to the point of parting it out as it has been giving me fits since back in june when i started the break in process.

o and by the way i started a wanted post for a shaft if anyone has one

[DnB_Racing]

so i have been having issues with my 330 overheating since day one. talked with eddie at esr and gave me a few things to check/try. one of them was to make sure the impeller had the small washer behind it. i checked it did. started reassembling and some how broke the shaft when torquing the impeller nut back down. i dont understand how i ,had the damn torque wrench on 8 ft lbs. any suggestions so if and when i get a new shaft i dont do it again? i am nearly thru dealing with this damn R. if someone could help me out it would be greatly appreciated. i am almost to the point of parting it out as it has been giving me fits since back in june when i started the break in process.

o and by the way i started a wanted post for a shaft if anyone has one

are you sure your tourqe wrench is calibrated acuratly ?

[trx250scar]

i have used it on everything else. could be outta wack i guess. maybe i will try my mechanic buddies high dollar wrench next time to eliminate any doubt.

[Rupp250]

Just because it is high dolar doesn't mean it is calibrated correctly. Or has been stored correctly. I would us an in/lb and set it to 96 in/lb. I don't like to use a wrench at 1 end of the specktrum it is designed for.