A A A A Author Topic: how not to repair a mechanical water pump seal lol  (Read 558 times)


how not to repair a mechanical water pump seal lol
« Started on: 29-Mar-20, 11:45 »
Hi all . ive always had fun and games doing the water pump seals on CX500s they either work fine first time or give me a lot of trouble ha ha . Im doing one as a charity Job for a social worker in southern tassie right now Jaffas CX500 custom and i didnt have the usual glue i have used with success in the past loctite 406 .Shep recommends blue hylomar but ive that fail to work for me last time for some reason twice as i tried the spray and tube type thin and thick .  black gasket silastic , red high temp gasket silastic and Threebond all failed dramatically with in 50 klms too for some reason oops .ive read a lot about the different glues people have used world wide some even recommended super glue but ill try Tarzan Grip mega bond ultimate strength glue this time as it advertised as water proof and high temp resistant. ill let you know how it gets on but im taking recommendations for next time in cas this fails again haha . the stock glue on most seems to be some hard setting contact adhesive so fingers crossed this will work .

i gave up removing the covers and pressing new seals in as i had trouble with 2 failing previously and when i checked the diameter of the steel cups they vary so much in diameter and i had some in 27 mm 27.8 , 28 , 28.4 , 29 , 30 mm as well as 32 mm depending on the sellers which is why if the steel cups in good cond i do the sheps method now but even that has given me some fun n games on 2 bikes .i guess some people just get lucky .if the cups slightly too big the cup will distort when you press it in or if the steel cup is too flat it rubs on the end of the cam shaft causing the glue holding the seal to fail. no need to ask how i know i had 2 fail a few years ago which is why i dont take paying jobs any more and retired but this one is for charity so i couldn't say no .wish me luck and keep safe


I have seen/heard the “Shep’s method” fail so many times that I never even bother to use it (I know some people never have a problem)

I choose to always remove the engine and do it the “hard way” but at least this way I can also check out the camchain, guides and tensioner and also check the oil seal behind the water pump.



Done a few now - done a couple of Sheps . One worked fine , one failed .

I find it takes less than an hour to pull a motor and swing it onto the bench . Then you can do all those other things you will wish you had done once you get the bike up and running .....


i totally agree its easy to drop the engine on a cx500 easier than almost any other motor cycle that size thats for sure .i had one bike have so many problems so many times i could drop the motor out in about 15 minutes if the tools were laid out but it takes a hour to put it back together single handed with a bad back lol and ive already had most of this bike apart in the past so ill just pull the seal and try a different glue . with luck it will be ok this time ill let you know if the new improved tarzan grip works .fingers crossed :) .i didnt try pressing a new seal and steel cup in as the seals i have were 28.4 mm and i wasn't sure what size hole the bike has and  i have had limited success with after market seals .i also cant find my last rear case gasket and ordering one from over seas will take up to 2 months ? and i dont have a old one to copy and i didnt want to risk re using a old one thats if it didnt tear on removal ..i dont want to pull it apart again hopefully agghhh ..i did trace the last new gasket i had but ive miss placed them .


update ..dont use tarzan grip or contact adhesive or any solvent based glues to glue in a water pump seal. though it says the new tarzan grip is heat resistant and water proof in the fine print it says not for use below the water line.

also 20 years too late i found out why other glues have failed. the solvent in many glues causes the rubber to distort and swell up pulling the seal away from the metal mating surface. sure wish id noticed that before now. good thing i pulled the new seal out to have a look and see where the water was coming form .

it might be  good idea to test any glue you plan to use on a old inner tube first before using it on a water pump seal.

so im back to wondering what glue to try next the stock glue is a hard setting glue that looks like contact adhesive so i might try loctite 401 as i dont have any 406 that i used last time left ( put it in the fridge or it goes hard in the bottle ) if it fails i can fess up about more failures :P


hmnn still scratching my head what glue to use to bond the rubber water pump seal to the stainless steel cup .on further research it says loctite 401 / 406 and super glue in general is not suitable for use under water , kinda interesting as the bike i used 406 on is still going as far as i know and the owner never reported the seal failing but maybe i just got lucky. says epoxy is no good either as it peels off rubber . any ideas people  ? i cant find anything at least available locally that will bond rubber to stainless steel and can be used under water where it gets hot .i guess most manufacturers say no just to cover themselves


Bostik ADHESIVE silicon.

Not silastic, it has no adhesive qualities at all.


resealed the water pump rubber seal with black gasket silastic a week ago and so far so good . last time we used it the cup was rubbing on the cam causing excessive heat build up so it might have failed because of the faulty steel cup  instead of the gasket silastic . ill keep you informed how it goes .we hope every one is doing well this easter good luck all


I would give Shoe Goo a try if nothing else works. It remains completely stable when cured and immersed under water and sticks well to rubber and most plastics. I regard Shoe Goo as a workshop in a tube.


Shoe Goo is a good product. I have a scope base glued to a rifle receiver with Shoe Goo and its holding up just fine so far


thanks ..i had a few of these types of glues and many replies saying they had worked fine but most do say not for immersion in water even the waterproof heat proof dust proof ones said not for use under water lol so i have a whole fridge full of glue now much to my ex wifes distress when she opens the fridge and tubes of glue etc fall on her hahaha


 :2afro: Shoe Goo, it is expensive but it works. Comes in black or clear.
Les F



I'm going to do a shep job as soon as my yamaha seal comes in and I can steal the guts from.

Shoe Goo or Bostic?




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