Modern Vespa

Two days ago while out exploring Alabama I experienced a catastrophic water pump failure @16,418 miles. After having covered about 220 miles for the day the rpms suddenly began to rise and fall while holding the throttle steadily at about 60 mph indicated. I immediately pulled to the side of the road and turned off the engine. The temperature gauge was normal. After inspecting the engine bay and not finding anything amiss I restarted the engine. Immediately there was a loud bang and coolant gushed out at which point I quickly turned off the engine. Thankfully I have a spare flywheel cover/water pump and impellor cover so hopefully that's all I need. Thank you Dobroman( https://modernvespa.com/members/dobroman ) for travelling 160 miles each way with your truck and trailer to fetch me home. Now to disassemble and inspect

Wow, catastrophic is the word. I'm just about to help replace a complete waterpump on my friend Louswheels 2010 GTS300, after a coolant hose popped off, dumped all his coolant and the ceramic seal broke (tricky to replace, requiring a rare special tool).

Is the flywheel cover plastic on the GT? I think they're now alloy on the GTS...

Any idea what caused yours to fail?

Wow that is catastrophic or at least in the neighborhood. Will also be curious if you can ascertain what happened. Good on you for getting it shut down quickly from at speed.

Ouch. when I first saw this, I was thinking a GTS waterpump cover would have been a good idea, but whatever happened took out the pump housing too.
Make sure your flywheel is turning freely without any noise. Sometimes they come apart and can do this.

ohhh... that does not look bueno....

more than likely you've lost the impeller drive which ate up the seal/bearing and then that whole mess dropped in and destroyed the plastic waterpump drive which possibly took out one of the drive studs and that's what punched thru the cover.

besides the new cover, i'd strongly recommend replaced the vulcanized drive studs as well. over time the rubber gets dried out and then breaks away, beating up the plastic drive and then boom goes the pump.

thankfully, that job isn't too terrible.

best of luck!

-g

I've gotten it all taken apart now. One stud is broken off of the flywheel and another one is bent. Thankfully I have a spare(used) flywheel, flywheel cover and water pump cover. My next concern is replacing the flywheel. The workshop manual is showing a special tool(adjustable wrench 020565Y) to hold the flywheel in order to remove the locknut and warns that using an improper tool could damage the stator coils. Do I have to order that tool or is there another one available locally(Sears, Harbor Freight, etc)? Also it is showing a special tool(flywheel extractor 008564Y) to remove the flywheel. Below is a picture of two flywheel pullers that my friend Dobroman is willing to loan to me. Will either of these work or is another appropriate tool available locally?

The "adjustable wrench" can be done without, most good tool shops will have something that is close enough in function, or you could make something similar. You can also use an air impact wrench for disassembly and a strap wrench to tighten it up.

The flywheel extractor is a must. it does not have to be piaggio but must be the the correct thread. They are not that expensive and can even be found on amazon, but you have to know the size and pitch of the thread.

Ah! quick search shows it being the same thread as the PX

http://www.scooterwest.com/item_details/Tool-Fly-Wheel-Puller-(Vespa-Piaggio)/2083?clear_cat=true

Thanks for that oopsclunkthud. I was hoping I could find an extractor tool locally. I will see if I can figure out the thread size. Sadly I don't have an impact wrench but might could borrow one. A strap wrench should be available locally. I was hoping to leave out next Wednesday for the Dead Elvis Rally in Memphis so ordering tools online is my last option.

Greasy, oddly the plastic water pump drive appears to be intact and spins freely.

Motovista, yep, definitely came apart.

stickyfrog, thanks, I would like to know what caused it too.

brown_beret7, the flywheel cover appears to be some type of cast metal. I believe the water pump cover is plastic. I don't know what caused the flywheel to fail.

patrick beat me to the punch on it, but a hearty +1 to his advise.

the flywheel puller is the same as p125/150/200 so you may be able to borrow it from somebody local.

don't use a jaw puller, you'll wreck the 'wheel for sure. you could probably use a universal three prong puller and thread into the drive stud threads, but again, that's somewhat risky in that you could damage the stator coils as mentioned in the manual. personally, i'd just drop the loot for the correct puller. also, that second puller in the photo doesn't actually appear to be a puller, but actually a flare tool for hard steel brake lines.

use an impact to blow everything apart.

now, don't quote me on this, but in a pinch you can use the impact to knock it all back together. the torque for the flywheel nut is not crazy at around 30~35 ft/lb so realistically you could set your air gun to stun and not kill and after giving it a bit of tightening by hand hit it for a few pneumatic seconds and call it done. but again, the proper torque value set forth by a proper wrench is the correct way to go about things.*

anyway, i strongly recommend some loctite on the new stud threads and on the SAS bolts if you removed them from the head... also, if you did remove the SAS tube, clean everything really well and give it just a little smear of ultra copper when you reassemble. while it's more work right now i'd also replace the SAS filters in the housing and the rubber joint pipes because it's all apart now.

a squirt of lube helps immensely on reassembly in getting the studs to seat into the holes of the waterpump drive.

hope that helps!
-g


*do as i say, not as i do. results not typical. controlled environment study. your mileage may vary. not liable for results therein. no warranty expressed or implied.

Greasy, thanks for the advice. Help me to understand clearly. Remove the flywheel stud bolts and apply Loctite to the threads and reassemble? Blue? Same for the SAS bolts at the head? Use ultra copper on both sides of the copper gasket where the SAS line mounts to the head?

I think that I will order the correct tools and stay away from the impact wrench. It may take longer to get it back together but I want to do it right.

yes, loctite on the studs. personally i prefer red, but blue is okay too. i'd use blue on the allens that hold the cover on. for the sas bolts, red for sure and a smear of ultra copper on the gasket is a good idea. just be sure to clean everything very very well.

good on you for going the extra mile and doing things the right way rather than cobbling together some fix. while it may take longer to get back on the road, ultimately it will be worth it in the long run in terms of a lasting, correct repair.

best,
-greasy

Thanks Greasy, I'm going to order the extractor this afternoon if I can't figure out the thread size and pitch and find one locally. I'll pick up a strap wrench to remove the lock nut. I appreciate the advice!

But you won't do as much damage as the guys who try to pry it off with a crowbar and hammer and break the case.
Seen that a few times.
Ideally, if you call a local scooter shop, you may be able to take it in and get them to use the puller to pop the flywheel off for you. Most shops have an assortment of pullers and should have the right one.

Thanks, I have just ordered the flywheel extractor and will purchase a strap wrench this afternoon. Hopefully I'll be back on the rode by this weekend

Hachi, glad this happened before, not during, the trip. I know you guys are looking forward to the rally next weekend. Looks like you've got it all sorted! Well done!

Thanks ScooterGirlinAL! No, I wouldn't want this to happen 300 miles from home. I hope that I can get it all back together in time for the rally

You've got a great start. I'm sure you will get it back together in time for your trip.

Well I got the flywheel and everything installed, started the engine and heard a noise from the transmission so I removed the case and inspected. I thought it was the clutch( GT 200 clutch repair help needed ) but the variator nut had come loose. I'm wondering how this could have caused the stud to break off of the flywheel or if it was coincidental. Anyway, I'm back on the road.

oopsclunkthud, thanks for pointing me in the right direction for the strap wrench and the flywheel extractor. They worked perfectly.

greasy, your advice was invaluable. I appreciate it.

Motovista, thanks for the preformed water pump cover o-rings. They were right on time.

ScooterGirlinAL, thanks for the encouragement. It means a lot.

YEAH! Sounds as though you are ready for the big Memphis trip. You guys will have a great time!

I hope so ScooterGirlinAL! I gave it a little ride around the neighborhood this afternoon and didn't notice anything out of the ordinary. Tomorrow I plan to go for a longer ride to make sure. I think Dobroman was worried that I wouldn't have it fixed in time but everything seemed to come together.

Well Done H! We're OFF!

Be careful of Capt. Gary's apple cupcake.

Jesse, wherever you are.......
WTF....every time I type p.i.e., (without the periods, I had to do that to fool the computer), it publishes "cupcake"
How can that be??????

Will do

Glad all worked out and Thanks for documenting the event and solution so well. I hope this will go in the archive for future reference.
There have been engine failures with two GT200's and a GTV250 belonging to members of our club lately. Two had valves broken and one ate a piece of the carb slide. Oh, the things that can happen!
The input of members here is invaluable.

Thanks Driller! The variator nut had worked itself very loose. My "theory" is that when the half pulleys separated enough it caused the belt to slip and the flywheel to over rev putting undue stress on the flywheel studs.

Its amazing how much knowledge and ability there is on this forum !

Hello all!

The waterpump on my GT200 just started leaking from the plastic inspection cover today and this thread came up in a search.

I've ordered a new cover already assembled with new bearings, seals, etc. but am still unclear on the replacement process.

The only video I could find online was for the fuel injected models, and calls for draining both oil and coolant and lowering the engine. Is this necessary on a 2004 GT200?

Also, the later models have a gasket for the cover, which I haven't seen mentioned anywhere for the GT200, so I understand the new cover is just bolted on, correct?

Reading through this thread I can see that the flywheel extractor is indispensable, and subsequent searches reveal the proper tool size to be an M28mm;1mm. Is that correct?

Lastly, my scooter just began leaking slightly. Is it still safe to use for short rides around town, or will this cause the pump to seize catastrophically, like happened to the OP?

Thanks!

Drain coolant only on the GT. No housing gasket, only o-ring at plastic cover. No need for flywheel puller, OP was replacing damaged part.

This is great information, many thanks!

Ok, so the parts arrived from S.I.P. today, including the water pump and flywheel cover, the seal and new vulcanised studs.

I just completed the repair, which was fairly straightforward. The 4 tiny allen head bolts holding the cover were tricky and I did need an impact screwdriver to remove the philips head screws on the impeller cover.

After buttoning it all back up I had two longish philips head screws left over whose location I forgot.

The scooter fired right up and I let it run until the fans kicked in to make sure there were no leaks.

Aside from the spare screws, it looks like the repair is done. Thanks especially to bluecloud for the sound advice.