coolant leak from weep hole

Joined
Jan 29, 2017
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SC
I've looked through a few threads but can't seem to find my answer. The threads go off topic, and then I'm just chasing my tail.

2003 ST1300 with 85k miles. Just got the bike a few months ago, figured I'd go through it real good. Fresh oil & filter, new fuel filter in the lower tank, checked the valves, new air filter, fresh pads and brake fluid, new spark plugs, final drive oil change.

I was used to seeing a small puddle of coolant under the bike upon cold startups, previously. To be safe, during this overhaul, I pulled the throttle bodies and found the thermostat hoses weren't constant tension, so I replaced the old hoses and the old OEM clamps with new hoses and constant tension clamps. Besides, the big one clearly had some minor leakage at one point in time or another. Started the bike up this morning, and confirmed I have no leaks anywhere, except the weep hole on the right side of the engine. From the looks of things, that's the better part of what was leaking before (not the top thermostat hose) What's the diagnosis? Do I need/should I rebuild the water pump? Any links to threads on the process?
 

SupraSabre

48 Years of SoCal Lane Splitting/Commuting-Retired
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Now that you replaced all the hoses up top and any leaks up there have been stopped, it's probably put more pressure in your system and causing your pump to leak more than it was. I did the same thing with one of my bikes. When I replaced the hoses (which I could see where they were leaking from), soon after, the waterpump started leaking!

There are some articles/treads for replacing the waterpump. Get yourself a manual and check out the following section, ST1300-Leaks


I'm sure someplace there will tell you how to do it. I've replaced one a number of years ago and have about three to do in the near future.
 

Whooshka

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BD I'll scan the pages from the manual and send it on today. It's weird, the manual says if there is weeping then the mechanical seal is shot and you need to replace the pump as a unit. Then the next section shows how to replace the seal. ????
 
Joined
May 6, 2013
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131
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Arizona
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8722
The water pump seal is mounted in the front cover of the engine, and is a fairly tedious job to replace. It sounds like you are comfortable with getting that deep into things, the only specialized piece of equipment you'll need is a shop or arbor press to press the bearing and seals out of the cover. There is a mechanical seal and an oil seal to replace. While you're at it, you may as well replace the impeller bearing too, and the O-Rings on the two water pipes. The replacement is pretty straightforward, if you are somewhat of an experienced mechanic. One tip... when removing the front cover (with the impeller), slide a thin stiff bit of metal behind the cover along the impeller drive, and in front of the chain driven impeller drive gear. This prevents the gear from coming too far forward with the impeller, and the drive chain dropping down into the crankcase.

Garry
 
Joined
Aug 9, 2010
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Vernon BC Canada
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09 ST1300
The water pump seal is mounted in the front cover of the engine, and is a fairly tedious job to replace. It sounds like you are comfortable with getting that deep into things, the only specialized piece of equipment you'll need is a shop or arbor press to press the bearing and seals out of the cover. There is a mechanical seal and an oil seal to replace. While you're at it, you may as well replace the impeller bearing too, and the O-Rings on the two water pipes. The replacement is pretty straightforward, if you are somewhat of an experienced mechanic. One tip... when removing the front cover (with the impeller), slide a thin stiff bit of metal behind the cover along the impeller drive, and in front of the chain driven impeller drive gear. This prevents the gear from coming too far forward with the impeller, and the drive chain dropping down into the crankcase.

Garry
+1 I recently did mine and used the press at work, and from that experience I think a hand pumped unit or an arbor press would be better suited to this task, you need to press the impeller back in a very specific distance, and I found that very difficult with the air-over-oil pump on our shop press. Do support the case with a receiving cup around the bearing when pressing in/out. Also I did not replace my impeller, as it was in very good condition but if yours has any wear at all particularly around the shaft where the oil seal rides, then certainly replace it. If I were to do it again I would replace the whole works.
 
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