Does this look like my mechanical seal is bad. I found some coolant leaking from the weep hole. If so Ill be looking for that seal. Does anyone know if the gas tank can be removed by pulling it forward under the rollbar/net, rather than pulling it straight up or back, seems like I remember pulling it out through the seat side?? Keywords...........FL400 Pilot water pump seal, water pump seal replacement, Pilot water pump, Pilot coolant leak, antifreeze leak

Put a paper towel on the hole for a min to soak up the liquid then head cycle the Engine again see if the coolant reappears.

You can remove the tank by removing the seat then removing the 5 bolts that holds the tank in comes out forward, only takes a few minutes to remove, don't forget to unplug the 2 wires for the low fuel light sensor.

I got home from work and noticed the weep hole was dry, too cool!, but then I did another heat cycle and it started leaking again, not cool. I thumbed through the manual on mechanical seal installation,i also found a post you did Hoser about the seal installation but the pics were distorted probably from that hack. Anyhow loooks like the right crankcase has to come apart. Can this be installed without removing the Engine. Do you think ill need a new crankcase gasket? Also do you have one o those seals. Im waiting for scpilot to respond I know he was selling off some parts.

You can change the mechanical seal with out removing the Engine or case for that matter, I did mine this way 2 or 3 years ago. Just pull the water pump housing, pull start assembly, & the little impeller. i drilled a couple small holes in the old seal and inserted 2 screws and then pulled the bad seal out the front with a pair of vise grips. I tried looking for pics from when I did it but all I could find were these.. be careful when drilling as there is a lip on the inside of the case if I remember right. I just missed it when I did mine, but remember I did come close.

I hope this helps & good luck..

Thanks for the reply Rarerat, and the pic. Ive never installed the seal so Im trying to figure this out. It looks like the reason to pull the crankcase cover is to replace the OIL seal, correct? So if I do it like you did I would just be replacing the two mechanical seal parts. So the mechanical seal is a back up seal to keep coolant from getting to the OIL seal and into the balancer crankcase?

Again if I didnt pull the crankcase apart, I would have to use a hollow driver like a deep well socket to install the mechanical seal since the shaft is there. Am I on the right track. Im sure Ill figure it all out when I get it apart but I wanted to get a scope of the work I would be doing beforehand. Thanks

I don't have my manual handy but if I remember right on the other side of the Mechanical seal is a bearing and another small seal. I"ve had to change mine twice. Steve & I changed the first one at his shop and we pulled the case and replaced everything. About 6 months later the Mechanical seal started leaking again, so I am guessing I must have had some trash in the cooling system that got back into the Mechanical seal and caused the leak. Anyway when it was apart the first time, the Mechanical seal is put in from the out side of the case towards the Engine and the bearing and the other small seal go in from the inside of the case towards the out side of the Engine. I hope that makes sense. lol.. Any way, yes I used a deep socket to install the new seal over the impeller shaft. It was pretty simple if I remember right, and knock on wood it hasn't given me any problems since.

Did you happend to see if the shaft where the seal rides was ok and not pitted or damaged,Ill have to remember to check mine. that's whats cool about this forum you learn crap you might not think of when doing these projects.

You know I am trying to remember.. I am probably wrong, but I want to say this seal doesn't seal with the shaft. There is a Nylon washer that it seals up to that makes the seal. It is spring loaded & that keeps the pressure between the Nylon and the other sealing surface if I remember right. I don't remember any pits in the shaft though..

Gotcha. I havent held the mechanical seal in my hand so I really don't know how it functions yet.

Those seals are Teflon covered by rubber on one piece and the other piece is like a hard plastic where the Teflon seals against. The hard plastic side is spring loaded to apply pressure against the Teflon piece, this is what seals it. This is all from memory so please do not quote me.

What I have seen on the seal is that the hard plastic side does not wear, the Teflon side is the part that lets it leak. The seals I have seen have little grooves cut in to the Teflon side, I think it is mostly caused by debris in the cooling system small pieces of sand or deposits etc.

One thing you could try if you have not pulled it apart yet is, unhook both coolant hoses that attach to the water pump inlet and outlet, hook a water hose to the water pump nipple and try flushing it, do the inlet and then do the outlet so as to back flush it. The hope here would be that a small piece of what ever is lodged in between the mechanical seals two surfaces and it gets dislodged from the flushing.

It would not take a very big particle in between the two surfaces to cause a leak.

I hope this helps.

Her is a picture from an en=bay auction, of the one I purchased from the UK. I have not installed it yet, but it appears to be the same as the oem one I have. I believe he has the Honda part number in his auction.

The picture will give some idea of what Steve is talking about.

http://www.ebay.com/itm/Mechanical-wate ... 3a8cc72f35

Yeah the seal is as scpilot66 described its a spring loaded affair.

I would try what scpilot66 said with flushing if that don't work you can remove the impeller and access the seal you might try that first see if their is anything on the seal surfaces that might be causing it to leak, the only way I have ever changed one was with the case off and on the bench I also changed the bearing and the oil seal that is only accessible from the backside, I have never seen one of the bearings go bad or the oil seal leak its a really reliable seal system.

I think I found the thread with the bad pictures I searched my computer and found good pictures and replaced all the bad check it out viewtopic.php?f=1&t=8912

See all the shit inside this one viewtopic.php?f=25&t=9407&start=25

PM sent

Hey I appreciate you going back and finding those pics. Make more sense now. Im sure I can tackle this but Ill flush the pump first. Hoping some debris from draining my system for the rebuild maybe worked it way into the pump. Thanks again guys!

Good day everyone, here are some part #'s for replacement mechanical seals for the pilot.
These are Honda seals and still available I think, I have not tried these or done a serious comparison to the oem seal but I got these #'s from someone that knows what they are talking about and I trust him completely.

I give all credit for this to him. Sorry, no I do not want to mention names. Not my place.

19217-MAL-300 http://www.partzilla.com/parts/detail/h ... L-300.html
19217-657-023 http://www.partzilla.com/parts/detail/h ... 7-023.html

Good luck, I hope the flushing works.

If the flushing don't work what are your thoughts on just removing the impeller cover then remove the impeller itself and cleaning the seal surfaces with a lint free cloth then assemble and try it again? That is if their is no visible damage to the seal surfaces.

Have you ever did a CSI on a automotive water pump they have a similar seal setup I have never seen a seal like the Pilot uses, hard plastic and what looks like a ceramic disc that mate and rub each other, I don't even see how its able to seal lol

That is a very good idea, then you would only need the water pump gasket.

As a matter of fact I think that you could probably get away with just replacing the half of the seal that sets in the water pump impeller, it is the part that gets worn from what I have seen. If the hard plastic side is worn as well then of course you would have to replace the whole seal.
I am not saying this is proper by any means, myself I would replace the whole seal.

A few other things that are possible but I doubt it, the spring could lose its tension, the spring loaded side could also develop a small tear or pinhole and the spring loaded part also has a sealant applied to it where it goes in to the case, I guess it is possible that it could leak there.

I have never taken a automotive water pump apart, I will cut one open sometime and see what it looks like.

You can take that white disc out if the impeller and flip it over and have a new side to reinstall facing the seal

EDIT
Yeah I confirmed it you can remove the white disc and flip it over, the used one I have here when I removed the disc from the rubber thing it had some black rubber residue on the back, I just took some softscrub and a flat piece of glass and lapped it a little it cleaned right up.

I ordered the mechanical seal Honda part number 19217-657-023 from Partzilla today. Ill post some pics and be the guinea pig on this one. If the flushing doesnt work then Ill see about installing this part.

No luck with the flushing. I flushed both directions and drained through the drain plug during flush also flushed with drain plug installed, also cranked Engine a few times during flush to maybe dislodge debris. Next is to replace mechanical seal unless theres anything else??

Remove the water pump cover then the impeller and look close at the seal surfaces see if their is something trapped between them you might try flipping over that white disc that's in the impeller re install the cover and leak test again.

Do you need a water pump cover gasket ?

I have a couple gaskets from recent rebuilds, thanks. Should I flip the washer or go ahead and install my new mechanical seal http://www.partzilla.com/parts/detail/h ... 7-023.html. That is if it shows up ffom Partzilla, they showed it it shipped from manufacturer and that it will ship on Monday, Fingers crossed. That part number was listed earlier in the post.

that's up to you on flipping it over if you wanted to verify its a quick fix for when seals are not available, probably only cost you a hrs time to flip/test? I don't know your machine if you have the OEM seat that only takes 2 min to remove or install if you have the ATVR suspension seat deal probably take an hr? Oil or grease both sides of the gasket you can probable reuse the gasket too heck I will donate a gasket for the cause

Ok so I have the impeller cover off and removed the impeller, I noticed a slight "up and down" and "left to right: play in the shaft, is that normal? Its a little but if its supposed to be bone tight then Rot Roh! Maybe why the seal went poof?