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Crofty

Water pump failure suspected

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Crofty

Hi  Last year I started a thread about coolant loss . Anyway I thought I had solved the problem with replacement hoses and I put the bike off the road at the end of Oct.  So fast forward to March get the bike out oil change etc check everything out after the winter and go for a  run. Coolant leaks back with a vengeance. got back home took off the belly pan and had a good look while the engine was running. Water dripping constantly from behind the water pump, so I guess it has been this all along as a few folk suggested it might be. So has anyone swapped a water pump out on a 700x, if so did you buy a second hand one or a new one. Is it an easy job etc ?  any comments welcome. 

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bonekicker

Steve it's weekend yet again-- someone who as changed the water pump will get back to you--but it may be later. :thumbsup:

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Crofty

Hi Michael, I am sure someone will. Pretty sure Howard had the same problem with using the same coolant as me.

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embee

I've had a pump off an NC engine (bare). You take the cover off first, then the body. This is because of clearances to the frame I think.The metal gasket comes off between them. Nothing complicated. The workshop manual shows which bolts are which, but it's easy to sort out.

There are a couple of 700  coolant pumps on the auction site at the moment around the £50 mark seems the going rate.

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Crofty

Thanks Murray, the clearances do look tight so that why its a 2 part strip then. I had seen a couple of second hand pumps on that auction site, I will get one and swap it out and then stick with the Honda coolant.  

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horobags

sure its not the gasket??

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Crofty

I never explained it very well, I meant failure of the gasket/seals. having looked at the manual now it looks like I can change the gaskets out by just taking off the cover and plate, rather than buying a second hand pump to change out. I was hoping someone who had done it might chime in.  

Edited by Crofty

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DaveM59

If it is dripping from the bleed hole then it is the inner seal that has gone and not the gasket. Using a non suitable antifreeze will accelerate this problem but it is also something that probably all pumps get like eventually.

Antifreeze not suited is actually getting harder to find as more and more cars and bikes are using the ceramic pumps, but check before buying that is is silicate free, organic acid technology (OAT) and it will be fine.

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Crofty

Thanks for replying Dave, it appears to be coming out the area where the weep hole is,but it is a bit more than dripping. it is  constant and during the course of a 100 miles today I lost quite a bit of coolant. I have used Rock Oil Kool as recommended by Wemoto for a few years but I see now they have discontinued it so I am thinking it wasn't silicate free. I have been looking at the diagrams the only seal I can see near the weep hole is 6.5mm sealing washer that looks like it slips over a 6x32mm housing bolt, it is only a few pounds and would certainly be an easy fix ?  

Edited by Crofty

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embee

It's likely to be the actual coolant seal behind the impeller. I don't think this is a serviceable part on the NC pump, but chances are it is a seal used by Honda on other bikes, unlikely they'd use a unique seal assembly just on the NC. It could of course be the O-rings each side of the metal shim.

 

There are folk around who can supply seals to suit, they usually consist of 2 parts, the spring loaded face seal and the "polo mint" ceramic part. There's someone supplying seals for Deauvilles which are, like the NC, supposedly not serviceable. IIRC they use a mixture of parts from other bikes, the seal element from one and the polo from another. Try a search on the auction site for "Honda water pump seal" and you'll see what's available, the question is which parts do you need since they are not listed as separate items for the NC, just the assembly. Need to take one apart and see what bits are used.

 

However, if you can pick up a serviceable used pump for £50 it's questionable whether it's worth the effort especially as you need the means to be able to get them apart.

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Crofty

Thanks again Murray, its difficult to know exactly so think I will have to pull it apart and see if I can learn more. I might try the weep hole seal first as that looks like a cheap and quick fix, if it turns out to be that. Get started on it on Mon, luckily I am retired so plenty of time. cheers for all the replies.  

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DaveM59

The two part seal design sound very much like that used on the X9 500 pump, parts of which are common to get from the likes of Fowlers. You never know Honda may he using the same parts, or rather Piaggio are, as there used to be a tie up with Honda and Piaggio many years ago.

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embee
2 hours ago, Crofty said:

Thanks again Murray, its difficult to know exactly so think I will have to pull it apart and see if I can learn more. I might try the weep hole seal first as that looks like a cheap and quick fix, if it turns out to be that. Get started on it on Mon, luckily I am retired so plenty of time. cheers for all the replies.  

I don't think there is a seal between the coolant and weep hole other than past the actual rotary seal. The O-ring 11 round the bearing spigot is for oil. I suppose it's also worth looking at O-ring 10 which is between the pump and cylinder head, it's the main coolant supply into the engine. Note it is not round the stub tube with the arrow E-18, that takes the pipe from the thermostat bypass, O-ring 10 is for a flat face seal to the cylinder head.

 

s-l500.jpg

 

https://www.bike-parts-honda.com/pieces-honda-detail-71541-71541-NC750XDE-2014-E_11-NC+750+X+ABS+DCT.html

E_11.jpg

Edited by embee

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Crofty

Hi Murray, thanks for putting the diagram up, I realised that O ring 10 did,nt fit on the hose spigot,It is a possibility that the leak is coming from the engine block connection. Think I can order all the seals and rebuild the pump with O ring 10 and the 2 gaskets and hopefully we should be fine. What do you think O ring 8 that fits on the 6mm bolt seals if not the weep hole ?

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embee

I think that bolt has an O-ring under the head because it is exposed to coolant inside the pump and therefore could leak. It goes through the dowel and screws into the blind boss you can see right in the middle on the pump photo, so won't leak out that side, but it is the only fixing inside the 2 sealing rings, all the other fixings are outside the sealing rings so are dry.

 

The weep hole, or as often called the "tell tale", is between the oil seal on one side and the coolant seal on the other. If either seal leaks it comes out of the tell-tale and doesn't go into the other side, so you don't get water in the oil or vice versa. This isn't the NC pump but shows the principle. The only real difference is that the NC oil side bearing is open to the engine for lubrication and the oil seal is between the bearing and tell-tale.

Honda-GL1000-Water-Pump-Seals.jpg

Edited by embee

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howard

Good morning! Yes, I did change my leaking pump for a new one (£200😞)from memory I removed all engine mounting bolts except the rear one which I just loosened. Then carefully jacked engine up or maybe lowered? To facilitate removal of one bolt which fouls on frame. This is probably not reccomended method but worked for me so please be careful and take your time, I accept no responsibility for any thing going wrong😉 I suspect proper way is to take engine fully out ! Good luck!

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Crofty

Hi Howard.  That sounds difficult, the manual suggest splitting the pump and removing it in two halves, I am going to try that first and see what the state of the pump internals are. 

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howard
On 18/03/2017 at 20:54, Crofty said:

Rock Oil Kool

Rock oil now do coolant called iced kool which is silicate free! Be careful of your choice of coolant, if it doesn't say silicate free it isn't😉

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Crofty

Hi Howard   I have to buy new seals so I will just get 5 litres of coolant from the Honda dealership. I phoned Rock Oil this morning and they confirmed that it isn't Silicate free. Pump off now and replacement from a low mileage model ordered from that auction site, less than 10k so hopefully still on factory coolant. Mine is on 40k and the system has had 2 Rock Oil Kool coolant changes and various top ups after valve checks so retiring the old pump and flush everything with fresh water. I suspect the hard part will be fitting the replacement.   

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howard

Good news then! Good luck

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Reckless

I had fun many times changing the mechanical seal in cx500's, engine out, rear engine cover off, knock old seal out, heat engine plate in oven, knock new seal in, rebuild. Someone came up with the idea of pulling the old seal apart whilst still in situ and sticking the new part in with silicone sealer, it worked and saved loads of time and effort, a Yamaha seal could be used too so the parts aren't exclusive.

Hope your repair is a total success  and frustration free.

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Crofty

Hi Bill got the replacement pump today so have ago tomorrow.  The silicone sealer might be needed for the gaskets as have to split the pump to get by the frame, so we'll see how it goes.  keep everyone posted.

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embee

Shouldn't need any sealant. the seals each side of the central steel shim are moulded rubber O-rings and as long as they're not damaged they should work OK on a refit. If in any doubt undo the pump halves, put the seals in a cup of hot water (anything up to boiling is fine) to soften and leave the seals at least overnight in a warm place, airing cupboard or similar.  They should relax and return more or less to original section. They're usually best without sealant, you can use a little red rubber grease if you wish.

 

Make sure the grooves they sit in are clean, carefully scrape out any white crusty corrosion.

Edited by embee

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trisaki

So Rock oil KOOL  isn't silicate free their new antifreeze  is they have been  selling  KOOL  for years ! 

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Crofty

Thanks for the hot water tip Murray, with engine in looks like you have to split the pump in order to get it behind the frame. But if the new pump is anything like the old one the gaskets should be held in place. I am going to put new oil and engine block o rings in, but I will take a chance on the gaskets.  Yes Mark it came as a shock to me that Rock oil Kool was silicate based as Wemoto have been recommending that coolant for the NC for 4 years at least. Got some OAT silicate free for the refill so fingers crossed !!

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