Water Pump Leak

[karlloss]

I have recently replaced the water pump shaft, bearing, bearing seal and impeller on my CRM, however the drain hole in the casing keeps leaking coolant, now on a car this would indicate a waterpump seal failure, however on inspection the seal on the water side of the bearing fine, however the drain hole in the casing starts in the recess that the silver metal cup sits in onto which the spring sits, this being the spring which applies pressure to the ceramic washer that runs on the rear of the impeller. I have rebuilt the assembly in the reverse order off the removal, am I missing a seal or is it that sealant needs to be smeared around the silver metal cup, seems strange that a drainage hole is in this location and no way of sealing it from what I can see. Any ideas?

[Active Rascal]

The small hole I 'think' you're referring to is labbeled as an 'inspection hole' and is roughlt 1.5-2mm diameter? I have also been told these are something to do with pressure release but not sure.

The actual coolant drain has a 6mm threaded plug in it and should be sealed with a copper washer. This is on the small water pump cover which covers the impeller and has 3 bolts holding it on. The 'cup' but forms part of the mechanical seal, and apparently should be replaced every time it's taken apart. Leisure Trail say they always renew this, never put one back.... I'm not surprised they say that when you see the price of the seal!!

I think a picture may help if you can upload one?

[karlloss]

Active, cheers. Yes I am referring to the 'inspection hole' not the coolant drain hole with screw bung. What I cannot see is how the 'cup' seals the hole without sealant, seems very strange set up to me. I have reused the cup, but being of softish metal I cannot see the need to replace it if all that seals the inspection hole is sealant. How much are the seals?