Removing ‘t Kreng’s water pump

With the replacement water pump for ‘t Kreng ready, I started on the final job. Fitting it to the engine. But before I could do that I first had to remove the old pump. Starting with the always rather messy job of draining the coolant fluid. But I am getting good at it as I only spilled about half a pint on the drive!

With the coolant drained from the engine I could begin with the removal of all the parts that are covering the water pump’s cover Starting with the coolant hoses, followed by the fuel lines, the throttle and choke .cables, the carburettors and the inlet manifold.

And this left me with the final parts. The water pump cover and the water pump itself. I did have some worries about the water pump’s cover, as they have a tendency to corrode solid into the engine. This being caused by galvanic corrosion between the alloy cover and the cast iron block. I needn’t have worried. The anti-seize paste I used 17 years ago did its job. The cover came out without any problems. The pump itself put up something resembling a fight but lost against my proven extraction tools.

With the pump out it was time to inspect all parts that had come off. To start with the infamous connecting tube (UKC2538) between the thermostat housing and the water pump cover. Those who follow this blog might remember that this tube had been leaking on and of for a few years. And there sure was a reason for that. The two rubber O-rings on the tube had completely dried out and hardened. And as such no longer effective in sealing.

Next item to check was the pump itself. And that too was rather obvious. The water seal underneath the impeller was completely worn. Actually so worn that the spring inside the seal had reached its maximum travel. Leaving the seal free from the underside of the impeller. With the brass bearing cage fitted the bottom of the water seal should be sitting just free of the water thrower disc. In this case there was enough room to move the seal up and down. And air gaps are pretty poor at sealing!

Final item to check was the water pump cover. I have seen a few over the years that were badly damaged by cavitation. Probably caused by incorrect coolant (plain water) in combination with an incorrect set gap between the impeller and the pump cover. But as can be seen in the picture above, this one turned out to be in pretty good condition. Cleaning and reassembly next.