TOPIC:

I have just replaced the mechanical seal in my 82 Z1300. After assembly and test run, the pump housing is leaking badly. Put in a new o ring, my guess is the O ring has failed or slipped. Has anyone else had this problem? Will have to dissamble and assess.

My new seal is doing that too but I think it may be because I made the mistake of running the engine without coolant for a while

I have removed and re-attached the coolant pump housing on a number of occasions. My experience has been that as with all precision engineering, cleanliness and surfaces free from corrosion are essential to get a good seal - this is particularly the case for "O" rings - the groove for the "O" ring needs to be clean and smooth and the outer surface also needs to be free of scratches and corrosion. Having said that, I always use a liquid gasket on the housing flat mating surfaces whilst avoiding getting any of this on the "O" ring or its mating surface.
Its easy to tell where the leak is coming from - a mechanical seal leak will deposit coolant from the drilling at the base of the block whereas the "O" ring will leak around the housing - I have had both over the years.

Picture below shows my housing - needed a clean up to remove corrosion in the groove:



This pic shows the tunnel for the housing in the block - face and inner diameter need to be clean and with no scratches or indents - liquid gasket applied to outer face only.

Thanks, much appreciated. My housing o-ring is not a tight fit, will get a better fitting o-ring and check everything again before reassembly.
Many Thanks

Use some GREEN "Scotch-Brite" to clean those surfaces and replace the O-ring. I like to apply a film of Silicone grease to O-rings. It helps the part slide in easier and reduces the tendency of the O-ring to roll.