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water pump

Posted: Tue Oct 09, 2012 3:28 pm
by jon h
Hi
Just started the bike after 7 yrs as a box of bits. Started first time bloody excellent, of course you couldn't see across the shed after 30 seconds. Anyway, the bad news is it dripping water (very little probably 5ml overnight) from the water pump breather. As i understand it that means water is either getting past the o ring on the shaft (shaft was a bit pitted) or past the carbon seal. this is wishfull thinking but if the leak is past the mechanical seal (new seal) do they bed in and stop leaking? i suppose it could be leaking past the lower of the two pump body o rings. what do you think?

jon

Re: water pump

Posted: Tue Oct 09, 2012 9:25 pm
by oldjapanesebikes
jon h wrote:Just started the bike after 7 yrs as a box of bits. Started first time bloody excellent, of course you couldn't see across the shed after 30 seconds.jon
So - to be clear, this was a full rebuild ? New water pump ? And you did add the StopLeak as recommended in the shop manual ? Often, it does take a bit for the seal to bed in, so a few drips I would not be concerned with unless it is still leaking after perhaps a couple hundred miles. On the other hand, if this was not a full rebuild, and re-used old original parts and no StopLeak - then perhaps you may need to pull it and do a proper refurbishment. As a minimum a new seal face and pump cartridge. These are still available from Suzuki. 8)

Re: water pump

Posted: Wed Oct 10, 2012 7:30 am
by Coyote
Check your transmission oil and make sure it's not milky. I had this problem with coolant getting into the tranny. It eventually healed itself. The bike had sat idle for 25 years in my case. All I could figure was the o-ring that seals the pump from the tranny had shrunk over the years. I did not have any external leaks

Re: water pump

Posted: Thu Oct 11, 2012 2:55 am
by jon h
Hi
Thanks for the replys. Somehow i,d got it in my head to actively avoid leak seal. I suffer badly from preconceived idea syndrome! Yet as you point out every manual including the Haynes i'm using says must add stop leak! The pump is old but all seals including graphite seal is new. Hope adding leak seal plus a degree of bedding in solves the problem. I'm using cheapish ethylene glycol based anti free i'm just assuming that is similar to coolant available in the 70s. Which coolant do people recommend.i replaced the o ring betwwen the crankcase halves and have no oil in water or water in oil as yet
Thanks again
jon h

Re: water pump

Posted: Thu Oct 11, 2012 9:22 am
by tz375
I also read those comments in the manual but had no leaks without adding any Stop Leak type product. I use a moderately priced antifreeze and it seems fine.

BTW, where did the replacement graphite seal come from?

Re: water pump

Posted: Thu Oct 11, 2012 10:23 am
by Suzsmokeyallan
I've reconditioned quite a few pumps already and one thing you have to watch out for is pitting on the shaft where the little o ring sits under the stainless seat. If the shaft is pitted there the coolant will weep pass the o-ring via the pits and head past the mechanical seal and out the weep hole in the case causing a small drip.
I've repaired shafts with good results so its not the end for the pump if they are not too badly pitted.

Re: water pump

Posted: Thu Oct 11, 2012 1:56 pm
by jon h
I got the mechanical seal from Crooks Suzuki here in the UK. The pump shaft was a bit pitted. i cleaned it up and then hoped it would be ok. I see both discountbikespares.co.uk and CMS in the Netherlands list a complete pump for around 200 dollars.
I have a second pump, shaft still pitted, may have a go at rebuilding it as Crooks list the mechanical seal at about 20 dollars.
Advice on shaft repair would be welcome. I read somwhere, maybe on this forum someone adding weld to the shaft then grinding or turning it back.
I'm still banking on the Stop Leak
thanks
jon h