Re: 1929 640 Water pump/fan hub pulley

Posted by DavidM On 2014/1/11 4:38:11

To clarify a few points.

The 633/626 Eight engines had front mounted or side mounted water pumps. The "problematic" water pumps are confined to the 633/626 cars with front mounted pumps. The 640/ 645 Super Eights all had the more conventional front mounted water pump similar in design to previous models.

The front mounted pumps on the 633/626 models were made to fit into a reduced space restricted by the fact that an eight cylinder engine was "show horned" into the space for a 6 cylinder engine. The front mounted pumps incorporate an internal gland seal nut that is difficult to adjust.

The two 633's that I restored both had front mounted pumps and they both now have a modern non adjustable mechanical seals which fixed the problem completely.

I do not know how many 633/626 cars had front mounted and side mounted pumps or which came first however the side mounted pumps are attached to a lug cast into the cylinder block so retrofitting a side mounted pump to a block made for the front mounted pump involves some non factory modifications to support the pump. The side mounted pumps are of a similar design to other models in that they have an external easily adjusted gland nut.

In my limited experience the front mounted pumps are more common.

The water pump pulleys are made from cast steel and are fragile. The shaft needs to be pressed out from front to back with the back of the pulley very well supported. Any force applied to the thin sections of the pulley will break them.

I would get the machine shop that broke the original to machine a new one from mild steel, not a difficult job.