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Water pump leak question
Posted: Tue Aug 07, 2018 5:51 pm
by tony g
Hi, on my newly 1500 miles ago rebuilt water pump it has an occasional leak from the slot. I know the carbon seal can cause a leak from the slot but can the top "O" on the brass cage ring also give the same symtoms?. Underside of impeller was cleaned up in lathe before fitting.
Cheers
Tony
Re: Water pump leak question
Posted: Wed Aug 08, 2018 6:39 am
by tony g
Anyone?
Tony
Re: Water pump leak question
Posted: Wed Aug 08, 2018 8:56 am
by xvivalve
Potentially, yes, but I’ve never seen one fail here; the brass cage is usually a tight fit on its own was the vertical wall of the block aperture scored in any way?
They can weep and reseal themselves after a period of lay up ; how often do you use it, and is your weep coincidental to starting to use it again?
Re: Water pump leak question
Posted: Wed Aug 08, 2018 11:11 am
by tony g
The bore wasnt scored last time I had it apart. This was my block that had the electric w/p and bung. I decided to ditch that set up and fit a rebuilt pump so back to standard apart from the reverse flow mods Ive made to the cyl head and stat housing set up. Been running and used a couple of times a week since feb so no lay up as such no. Strange thing is Ive been losing water with no trace so suspected h/gasket. Last night I pulled into drive whilst turning left and when I got out I saw a few sp[ots of water on the ground which basically had come from the slot. Within a minute or so the ground was dry as so was the block hence maybe never finding the leak.
Ive got spare pump bits with me and a rebuild kit coming from Robsport (with new block bush). Stripping it tonight and if theres not enough to make me think it was a dodgy seal or fitting problem the heads coming off. I have isle of Man trip in 2 weeks so I need to get it back on the road quick for road testing before the Liverpool trip
Cheers
Tony
Re: Water pump leak question
Posted: Fri Aug 10, 2018 7:47 am
by 80Sprint
Can you get some more miles on it first. I would be reluctant to take the head off if the water is coming out of the slot unless it's coming out of the head and running down. If it's out of the slot it should only be a pump issue.
Re: Water pump leak question
Posted: Fri Aug 10, 2018 8:51 am
by tony g
Yes Ive built a spare pump up this morning and will fit it this afternoon and run it and see

Robsport next day delivery is a bonus too.
Cheers
Tony
Re: Water pump leak question
Posted: Thu Aug 16, 2018 10:03 am
by trackerjack
tony g wrote: ↑Fri Aug 10, 2018 8:51 am
Yes Ive built a spare pump up this morning and will fit it this afternoon and run it and see

Robsport next day delivery is a bonus too.
Cheers
Tony
I assume you lightly grease the brass cage "o" rings before fitting as perhaps a torn ring could cause a leak. Yes I know grandma suck eggs but you might just have forgotten to do it. Plus I have taken enough engines apart to know that lots are not and the brass cage is stuck in because it was dry fitted.
Re: Water pump leak question
Posted: Thu Aug 16, 2018 12:32 pm
by tony g
Yes it was greased Jon, however on removal again I couldnt find anything wrong so I cleaned up the o ring on the top side and put it back together with rtv around it and its stopped leaking. I mnever thought the fit was quite tight enough really so maybe my block had been rubbed a bit hard with emery cloth to clean it up. So far so good I think
Cheers
Tony