Leaking water pump seal 300 4T 2017

[Dean K]

I just came home from riding to find coolant dripping from right under the water pump, I have read there is a weep hole there that will drip if the outer water pump shaft seal in going bad. I see no evidence of water in the motor oil so I assume the inner water pump seal is still sealing. After looking up what parts I need I can only find one part number, but there are two seals.

1. Does anyone know if you order the one number and it comes as a kit with two seals? Or do I order two of that part number and they are the exact same seals? 

2. I see there is a special water pump shaft removal tool. Do I need it or can I just dig the old seals out carefully?

3. If I need and use the tool does the gear drive and bearings stay in place when I remove the shaft and is it reverse thread or standard to loosen it?

I have about 300 hours on the motor, is this about average time for a seal failure? I will check the water pump shaft for any wear also when I get into it.

Thanks in advance for your help, Dean 

 

[Bm1200]

Had the seals go on my 2012 300 4t. 
 

this is what I did

lay bike on side

remove weather pump cover

remove circling and impeller

used home made tool to unscrew water pump shaft. The benefit of having the bike on its side is the drive sprocket doesn’t fall into the engine. I dropped a small rod in just to keep it still until I put the new shaft in. Mine needed replacing because the seals had worn deep grooves new shaft cost £80 !

lever out seals

I bought new bearings but they are tricky to get out. I decided to leave them rather than fail to get them out and damage them in the process. 
 

the seals go front to front. Ie the open spring side on the inner seal faces cam chain tunnel and the outer is open side to the water so that the pressure improves the sealing force.

I bought beta seals but they seemed like hard viton that may increase the shaft wear. I put in some cheap nitrile ones that are fine after 2 years. 
I put red rubber grease in between the seals. I notice that this is now shown as an annual service item since 2018.

The tool I made was dead simple. Get an M8 nut and drill it out 9.5 mm cut a slice off one side to end up with a D shape 7.5mm across. I welded a bit of metal to close the straight edge of the D and filed it back to a hex. Tap it on stick a socket on it and give it a sharp tap!

 

Hope this helps

 

Nige

[Dean K]

Nige thanks so much for the reply. I'm going to make a tool like you showed me. To loosen the shaft do I turn it clockwise. It seems the way the veins are and the rotation it would be that way to self tighten when running? What seals did you find that are softer? I agree with you that they should something different because of wear. I had the same issue with my Gas Gas as there seals had a hard lip that would wear out the shaft very quickly. Maybe they should use a harder shaft material.

[Bm1200]

No problem the thread is normal so anticlockwise undoes.

I got my seals from simplybearings in the uk size 10 x 18 x 4

inner bearing is HK0608 outer bearing HK1010 ( still in the spares box)
 

Special tool sounds a bit grand now I look at it

[Bm1200]

A better pic of knackered shaft

[Dean K]

Yeah after I asked you I was explaining to a friend of mine the rotation of the shaft and figured that I had said the wrong direction since the shaft rotates counter clockwise, that standard rotation would be self tightening. But it is good to hear it from someone who has done it before. Did you use torque wrench (ft. pounds) to set the shaft back on and if so how did you stop the engine from turning. I have heard there is a spot for a bolt to hold the flywheel, but I really don't want to open up the sidecase cover to do that. Wow, your shaft has some pretty good wear on it. Twice my Gas Gas shaft looked like yours. My Beta has a very fine groove just starting to appear. I might be able to still use it and just put on a new outer seal since it seams like this is going to be a re occuring problem and you have said the shafts are very expensive. I'm thinking that with the two seal set up and a weep hole it will always give me fair warning as to when the outer seal is starting to go but the inner seal will keep coolant from going into the motor unlike my Gas Gas the coolant goes directly into the engine when it starts to leak. I know replacing everything while it is open makes sense, but it is so easy to get to it might be more cost effective for me. If anyone can chime in on my thoughts, please do.

I forgot to think that I live in the USA so I guess it would be up to me to find seals that are softer if I decide to go that route. 

Have you heard of a bigger impeller for this bike that helps it cool better and maybe lasts longer. I have heard some things, but can't find any info about it for the 4t. It might just be for the 2t only??

Thank you again for all your help,

Dean

[Bm1200]

Hi Dean

Have you found the 4t engine manual online, it shows the locking bolt in the crankcase. I didn’t bother , with he mass of the crank I was able to undo it with a sharp tap and did the same to tighten it. I couldn’t find a torque any where. I haven’t seen a high capacity pump for the 4t but don’t have any problems in the uk climate. 
 

I popped the shaft out after a year and stuck some more grease in. With the ordinary nitrile seals there was no signs of wear. The more recent manuals show this as a 40hr service and 80 hr seal replacement. Will have another look in January.

[Dean K]

Hi Nige, 

Yes I saw the shop manual, that is where I heard about the locking bolt. I had a chance to knock the shaft loose today, quick tap and it was free. I looked at the shaft again while it was out and found that the outer seal area was worn more that I could see by just peeking into the seal when it was on the bike and the inner seal area n the shaft was fine . I have ordered a new shaft and a couple of factory seals for now. I may just replace the outer since the inner showed no wear. I'm thinking the inner one probably lasts longer because it gets lubed from the engine oil.

I will look for the service note that talks about the hours of service and grease to use. I'm wondering if you fill the space between the two seals with grease, if that will kinda plug the weep hole to where you won't know when a seal has gone bad? What is your thought?

I am very interested to hear what you find on the seal wear in January.

We also might use Hondaline coolant as it does not contain any silicates, Honda is very picky about what coolant to use on there bikes and they state that other coolants will wear out the seals on their waterpumps. I'm not sure if the coolant Beta recommends is silicate free or not. Food for thought.

Thanks for time helping me with this,  Dean

 

[Bm1200]

I had never heard of the silicate issue. Must admit I was going for metal compatibility having seen some pretty horrible corrosion/erosion of some high magnesium alloys but will be going for silicate free in future. Mine leaked it’s water into the sump didn’t help that the vent hole was blocked with degraded grease which is why I used red rubber grease which seems to have great water resistance compared to other greases I have used.

Will post another pic next time I get the shaft out.

 

Nige

[Dean K]

Sorry for the late reply, I have been away on a trip. Yeah, I thought that too much grease might clog the weep hole and makes it useless as a warning that a seal is failing. I have some silicone seal grease that was recommended for my Gas Gas water pump seal that i'm going to try, I will use it sparingly and see how it works, I don't want to block the weep hole. I have been using the Hondaline coolant on all of my watercooled bikes, it makes sense to me.

It will be interesting to see your shaft wear when you take it apart next.

Thanks, Dean

 

 

 

[Bm1200]

Hi Dean

Lock down has given me the chance to do a bit more maintenance, so while the engine is out I popped the water pump shaft out and took the attached pic. The seal surface is visibly polished but no detectable groove or edge you cam feel after two years, probably around 80 hours, Grease was still present with no signs of leakage. Re-greased with red rubber grease for another year.

[Bm1200]

[Dean K]

That shaft still looks very good. That is with using non OEM seals right. Mine just started to leak again (OEM seals), maybe 50 hours. I haven't taken it apart yet to see if the shaft is worn or the seals are faulty, kinda bummed it happened so quick. I will update you on what I find. Thanks for your update. 

[carlos]

The stock water pump seal is a 10x18x4, on my 2016 4T300, with over 250 hours it started to weep, replaced it with the stock seal, but the autoparts guy said they had 10x18x6 seals.  Was thinking you may just have enough room to use the slightly wider seal, which would then contact the shaft at a different (unused) point on the shaft.  Would be close as you still need to let enough room for the water to leak out when the seal finally goes.  Would save having to buy and install a new waterpump shaft.  Will try it when the new seal starts to leak.

 

[Dean K]

Let us know if it can be done and not block off the weep hole. Might be a way to extend the life of the shaft. I can't recall where the weep hole was in relationship to the seals, but I will check when I take mine apart again also.