M38 water pump and crankshaft pulley alignment

Brumbach · Post by **Brumbach** » Thu May 24, 2018 4:46 am

With the water pump installed, the two pulleys are out of alignment by .129 inches. Water pump pulley is forward. Water pump pulley has been pressed on flush with the water pump shaft. Is the misalignment acceptable or should I have the water pump pulley pressed more to improve alignment? Thanks in advance.

OKCM38CDN · Post by **OKCM38CDN** » Thu May 24, 2018 6:14 am

Press it on more... will not hurt it any... so long as you brace the innards of the water pump and only move the pulley...

Post by **wesk** » Thu May 24, 2018 11:09 am

This should be a WARNING

so long as you brace the innards of the water pump and only move the pulley

To do this properly requires removal of the pump from the engine. Then pressing the pulley with the impeller firmly supported to prevent damage to the bearing or it's retainer clip.

The rebuild instructions for the pump are in your TM 9-1804A for the M38 and TM 9-8015-2 for the M38A1.

Brumbach · Post by **Brumbach** » Thu May 24, 2018 2:32 pm

I'm in the final assembly of the engine. I did a dry install of the water pump to determine the misalignment. Unfortunately, no one in this small town is willing to attempt pressing the water pump pulley to take up the slack. Guess I'll have to do some travelling.

Post by **wesk** » Fri May 25, 2018 2:09 am

It will be difficult to get the pulley positioned in one try and even more so without the engine to use for checking alignment.

You should be able to do this yourself. Even do it on a large vice. Just use a socket between the vise and the pulley.

Brumbach · Post by **Brumbach** » Fri May 25, 2018 3:13 am

I'll give it a shot! Thanks