Water pump rebuid kit problem
Post Reply    Forum -> General Discussion
Author Message
Hooked
2009 250
Joined: 13 Oct 2019
Posts: 127
Location: Canada
Thu Oct 24, 2019 5:44 pm quote
I pressed the 2 new bearings and the slotted end piece on the new shaft using a vise and some sockets.

I can't tighten the impeller on the shaft because the pressed on slotted piece turns on the shaft. It's not a very tight fit and I can pull it off with my fingers. Should heat be used when pressing the slotted piece on the shaft for a tighter fit?

Some differences with the impellers also. Old impeller has a Piaggio symbol on the back, new one has nothing. Brass nut is taller on the new one also.

Is this a common problem?

105.jpg
New left, old right

106.jpg
New left, old right

107.jpg
New left, old right

Enthusiast
GTS 300, BV250
Joined: 29 Jun 2018
Posts: 58
Location: Orange County, CA
Thu Oct 24, 2019 7:21 pm quote
I don't know if it's common but the same thing happened to me. Cheap aftermarket parts with zero quality control are probably to blame..

Contact the vendor for a refund and buy another kit from another source. You might be able to just move the bearings onto the old parts if they're not too crunchy and call it a day.

Be glad that you caught it in time!
Hooked
2009 250
Joined: 13 Oct 2019
Posts: 127
Location: Canada
Thu Oct 24, 2019 7:36 pm quote
The vendor's description says "kit components are made using OEM parts" and "the most complete OEM water pump repair kit for Vespa 250"

That's just fancy advertising I guess? I thought I was getting the real thing?
Hooked
2009 250
Joined: 13 Oct 2019
Posts: 127
Location: Canada
Thu Oct 24, 2019 7:44 pm quote
GotMojo wrote:
Be glad that you caught it in time!
I caught it after the shaft and bearings and two seals were pressed into the water pump housing.
Enthusiast
GTS 300, BV250
Joined: 29 Jun 2018
Posts: 58
Location: Orange County, CA
Thu Oct 24, 2019 9:02 pm quote
S.Ro wrote:
GotMojo wrote:
Be glad that you caught it in time!
I caught it after the shaft and bearings and two seals were pressed into the water pump housing.
You caught it before you rode off into the sunset and grenaded your engine.

You caught it in time.
Sponsor
Granturismo 218
Joined: 04 Feb 2013
Posts: 6075
Location: NWAOK
Thu Oct 24, 2019 10:05 pm quote
Re: Water pump rebuid kit problem
S.Ro wrote:
I pressed the 2 new bearings and the slotted end piece on the new shaft using a vise and some sockets.

I can't tighten the impeller on the shaft because the pressed on slotted piece turns on the shaft. It's not a very tight fit and I can pull it off with my fingers. Should heat be used when pressing the slotted piece on the shaft for a tighter fit?

Some differences with the impellers also. Old impeller has a Piaggio symbol on the back, new one has nothing. Brass nut is taller on the new one also.

Is this a common problem?
Sure, if you try to install it with a vise and sockets. You need a press, and to put it together correctly. The shaft is pressed down through the bearings and pressed into the slotted piece in one fell swoop, so to speak. That's what you install in the housing. The odds are that you're not getting 12 tons of pressure when you're trying to stick the slotted piece on the end of the shaft once you've got it installed in the housing. .
Hooked
2009 250
Joined: 13 Oct 2019
Posts: 127
Location: Canada
Fri Oct 25, 2019 6:39 am quote
12 ton press? I can push and pull the water pump drive boss off and on with my fingers. Will pushing it on harder make it stick better? Is it seated all the way in my pic? Maybe a millimeter of the shaft is exposed.

IMG_20191025_102747230.jpg
10:27:47am

IMG_20191025_102806398.jpg
10:28:06am

Sponsor
Granturismo 218
Joined: 04 Feb 2013
Posts: 6075
Location: NWAOK
Fri Oct 25, 2019 7:35 am quote
It needs to be pressed on with a press. You are supposed to put it on the bottom of the stack, then the bearings, and press the shaft down through all three of them, then install the part as a whole. It sounds like you tried to stick it on the shaft after you'd installed the bearings in the cover.
Veni, Vidi, Posti
Neutrino MP3 492.7 AK, 2013 Moto Guzzi Norge
Joined: 29 Mar 2008
Posts: 21579
Location: Harriman, Tennessee, Tn
Fri Oct 25, 2019 9:08 am quote
S.Ro wrote:
The vendor's description says "kit components are made using OEM parts" and "the most complete OEM water pump repair kit for Vespa 250"

That's just fancy advertising I guess? I thought I was getting the real thing?
return it for a full refund. those are cheap aftermarket parts you got and order from a vespa dealer the correct parts.

I recommend AF! racing and Scooterwest They both are excellent in their service and parts.
https://www.af1racing.com/store/Scripts/prodView.asp?idproduct=96603&sku=AF1-8447595&description=OEM+Vespa+Water+Pump+Rebuild+Kit
Ossessionato
2018 Vespa GTS 300 ABS- Bianco
Joined: 20 Apr 2013
Posts: 2156
Location: E. KY
Fri Oct 25, 2019 9:39 am quote
Assuming the bearings are in the correct position, are you saying the last part "drops" onto the shaft rather than require pressing force? As in a sloppy fit?
Hooked
2009 250
Joined: 13 Oct 2019
Posts: 127
Location: Canada
Fri Oct 25, 2019 9:42 am quote
old as dirt wrote:
S.Ro wrote:
The vendor's description says "kit components are made using OEM parts" and "the most complete OEM water pump repair kit for Vespa 250"

That's just fancy advertising I guess? I thought I was getting the real thing?
return it for a full refund. those are cheap aftermarket parts you got and order from a vespa dealer the correct parts.

I recommend AF! racing and Scooterwest They both are excellent in their service and parts.
https://www.af1racing.com/store/Scripts/prodView.asp?idproduct=96603&sku=AF1-8447595&description=OEM+Vespa+Water+Pump+Rebuild+Kit
They are aftermarket parts? Vendor says they are OEM. Luckily my bearings are still in good shape and will reuse the shaft and bearings. Can't return it as I'm using the o-ring and 2 seals. Lesson learned.
Hooked
2009 250
Joined: 13 Oct 2019
Posts: 127
Location: Canada
Fri Oct 25, 2019 9:44 am quote
Kantuckid wrote:
Assuming the bearings are in the correct position, are you saying the last part "drops" onto the shaft rather than require pressing force? As in a sloppy fit?
Yes. Bearings are a nice tight fit on the shaft but the slotted end piece I can pull and push off with my fingers.
Veni, Vidi, Posti
Neutrino MP3 492.7 AK, 2013 Moto Guzzi Norge
Joined: 29 Mar 2008
Posts: 21579
Location: Harriman, Tennessee, Tn
Fri Oct 25, 2019 10:24 am quote
S.Ro wrote:
old as dirt wrote:
S.Ro wrote:
The vendor's description says "kit components are made using OEM parts" and "the most complete OEM water pump repair kit for Vespa 250"

That's just fancy advertising I guess? I thought I was getting the real thing?
return it for a full refund. those are cheap aftermarket parts you got and order from a vespa dealer the correct parts.

I recommend AF! racing and Scooterwest They both are excellent in their service and parts.
https://www.af1racing.com/store/Scripts/prodView.asp?idproduct=96603&sku=AF1-8447595&description=OEM+Vespa+Water+Pump+Rebuild+Kit
They are aftermarket parts? Vendor says they are OEM. Luckily my bearings are still in good shape and will reuse the shaft and bearings. Can't return it as I'm using the o-ring and 2 seals. Lesson learned.
well its obvious that vendor is a liar and a shame, as those are NOT OEM parts. Sorry you have to deal with crap like that.
Hooked
2009 250
Joined: 13 Oct 2019
Posts: 127
Location: Canada
Fri Oct 25, 2019 12:10 pm quote
old as dirt wrote:
S.Ro wrote:
old as dirt wrote:
S.Ro wrote:
The vendor's description says "kit components are made using OEM parts" and "the most complete OEM water pump repair kit for Vespa 250"

That's just fancy advertising I guess? I thought I was getting the real thing?
return it for a full refund. those are cheap aftermarket parts you got and order from a vespa dealer the correct parts.

I recommend AF! racing and Scooterwest They both are excellent in their service and parts.
https://www.af1racing.com/store/Scripts/prodView.asp?idproduct=96603&sku=AF1-8447595&description=OEM+Vespa+Water+Pump+Rebuild+Kit
They are aftermarket parts? Vendor says they are OEM. Luckily my bearings are still in good shape and will reuse the shaft and bearings. Can't return it as I'm using the o-ring and 2 seals. Lesson learned.
well its obvious that vendor is a liar and a shame, as those are NOT OEM parts. Sorry you have to deal with crap like that.
Looking at that Af1 link you posted and it doesn't come with the slotted piece (water pump drive boss)?

Description says...

Kit includes:

Water Pump Shaft w/Bearings
Water Pump Drive Spring
Water Pump Cover O-ring
Water Pump Impeller
Water Pump Mechanical Seal
Water Pump Seal

And the pic doesn't show it either...

AF1-8447595.jpg

Veni, Vidi, Posti
Neutrino MP3 492.7 AK, 2013 Moto Guzzi Norge
Joined: 29 Mar 2008
Posts: 21579
Location: Harriman, Tennessee, Tn
Fri Oct 25, 2019 1:00 pm quote
S.Ro wrote:
old as dirt wrote:
S.Ro wrote:
old as dirt wrote:
S.Ro wrote:
The vendor's description says "kit components are made using OEM parts" and "the most complete OEM water pump repair kit for Vespa 250"

That's just fancy advertising I guess? I thought I was getting the real thing?
return it for a full refund. those are cheap aftermarket parts you got and order from a vespa dealer the correct parts.

I recommend AF! racing and Scooterwest They both are excellent in their service and parts.
https://www.af1racing.com/store/Scripts/prodView.asp?idproduct=96603&sku=AF1-8447595&description=OEM+Vespa+Water+Pump+Rebuild+Kit
They are aftermarket parts? Vendor says they are OEM. Luckily my bearings are still in good shape and will reuse the shaft and bearings. Can't return it as I'm using the o-ring and 2 seals. Lesson learned.
well its obvious that vendor is a liar and a shame, as those are NOT OEM parts. Sorry you have to deal with crap like that.
Looking at that Af1 link you posted and it doesn't come with the slotted piece (water pump drive boss)?

Description says...

Kit includes:

Water Pump Shaft w/Bearings
Water Pump Drive Spring
Water Pump Cover O-ring
Water Pump Impeller
Water Pump Mechanical Seal
Water Pump Seal

And the pic doesn't show it either...
you should reuse the slotted piece unless its damaged in someway. all the other parts are the wear parts to replace.
Ossessionato
2014 Commuter BV350(43,000)/2015 Scoot Life BV350(10,000)/2010 El Diablito SH150i(29,000)
Joined: 27 Dec 2013
Posts: 2428
Location: Orange Park Florida
Fri Oct 25, 2019 4:54 pm quote
If the boss has a hole all the way through, you can push the boss off the old shaft and see if it will press tightly on the new shaft. Use the socket and a bolt that is just smaller than the hole in the boss.

Being a machinist, I don't believe that using a vice as a press will alter a press fit tolerance. A vice is just a little less convenient than a press. If you don't have a fist on the end of your dick, you may need help turning the handle while holding 3 separate pieces in place.

The only way to know if the shaft and the boss has the correct fit, is to measure them with a small hole gauge and micrometer.

Good luck.
Moderaptor
The Hornet (GT200, aka Love Bug) and 'Dimples' - a GTS 300
Joined: 26 Aug 2007
Posts: 38411
Location: Pleasant Hill, CA
Fri Oct 25, 2019 5:06 pm quote
I always buy the whole housing - only a bit more cash than buying the kit, and a whole lot less hassle! Plus you know you're getting real OEM parts.
Hooked
2009 250
Joined: 13 Oct 2019
Posts: 127
Location: Canada
Fri Oct 25, 2019 6:28 pm quote
breaknwind wrote:
If you don't have a fist on the end of your dick, you may need help turning the handle while holding 3 separate pieces in place.
You don't need to hold the three pieces once you have pressure on them. That way you can stand as far away as possible and turn your head so you don't catch something in your teeth if it goes kablooey .
Pressing the bearings on took force.

Last edited by S.Ro on Fri Oct 25, 2019 6:40 pm; edited 1 time in total
Hooked
2009 250
Joined: 13 Oct 2019
Posts: 127
Location: Canada
Fri Oct 25, 2019 6:30 pm quote
jimc wrote:
I always buy the whole housing - only a bit more cash than buying the kit, and a whole lot less hassle! Plus you know you're getting real OEM parts.
I've learned my lesson! I wish I would have meet you 2 weeks ago. Would've saved me some hassle.
Enthusiast
GTS 300, BV250
Joined: 29 Jun 2018
Posts: 58
Location: Orange County, CA
Fri Oct 25, 2019 8:12 pm quote
Motovista wrote:
It needs to be pressed on with a press. You are supposed to put it on the bottom of the stack, then the bearings, and press the shaft down through all three of them, then install the part as a whole. It sounds like you tried to stick it on the shaft after you'd installed the bearings in the cover.
The results would be the same. The tolerances aren't right. It's a bad part or parts.

The kit from Scooterwest did not have this problem.
Hooked
2009 250
Joined: 13 Oct 2019
Posts: 127
Location: Canada
Fri Oct 25, 2019 8:36 pm quote
ScooterWest says the bearings and water pump drive boss are already pressed on the shaft. Is that true? Does the back of the impeller have a Piaggio symbol and PA66 marking?

https://www.scooterwest.com/complete-water-pump-overhaul-kit-vespa-gts-8447595-kit.html
Hooked
2009 250
Joined: 13 Oct 2019
Posts: 127
Location: Canada
Fri Oct 25, 2019 8:50 pm quote
Went and recreated my technique and took a pic. 8mm deep socket on the threaded end of the shaft and a 15mm socket on the water pump drive boss. Cranked the vise as tight as I can. It doesn't make a differance. When I take the assembly out I can pull the water pump drive boss off the shaft with my fingers.

109.jpg

Sponsor
Granturismo 218
Joined: 04 Feb 2013
Posts: 6075
Location: NWAOK
Sat Oct 26, 2019 5:03 am quote
GotMojo wrote:
Motovista wrote:
It needs to be pressed on with a press. You are supposed to put it on the bottom of the stack, then the bearings, and press the shaft down through all three of them, then install the part as a whole. It sounds like you tried to stick it on the shaft after you'd installed the bearings in the cover.
The results would be the same. The tolerances aren't right. It's a bad part or parts.

The kit from Scooterwest did not have this problem.
That's because they are pressing the parts together for you, and eliminating one of the most difficult steps, so you're not trying to do it yourself without proper tools or experience. You do have to press the shaft straight down into the bushing for it to work properly, and that's almost impossible without a press.
You're basing your statements solely on your own experience doing this once, and then buying a kit that someone else had partially assembled. These kits are from Italy, are assembled with OEM and OEM quality parts, and are sold all over Europe and the world. I know for a fact that most of the parts that you installed both times came from the same manufacturers.
Even our kits for Kymco scooters come out of Italy, but they source parts in Taiwan, for the most part. Over the years, we've sold over 200 kits for the Vespa GTS alone, and the company that we get them from has sold tens of thousands, for a lot of different makes and models. You can purchase them on Ebay and Amazon in every country in the EU.
If shops that purchase them from us on a regular basis and have the tools to do it correctly have problems like this, there's a concern, and there's a bigger problem for the company we get them from.
We sell water pump repair kits for most major brands of scooters, and no matter the make or model, people who've never done this before and don't know how to do it right or have access to a shop press, are the ones who have problems. If a shop buys it, that's the lasts we hear about it.
Personally, if it's my bike, I do what JimC said.
Enthusiast
GTS 300, BV250
Joined: 29 Jun 2018
Posts: 58
Location: Orange County, CA
Sat Oct 26, 2019 7:03 am quote
Motovista wrote:
That's because they are pressing the parts together for you, and eliminating one of the most difficult steps, so you're not trying to do it yourself without proper tools or experience. You do have to press the shaft straight down into the bushing for it to work properly, and that's almost impossible without a press.
You're way off base here. I have put together a few of these (and mangled a few in the process) so I know how it's supposed to be done. None of the kits I bought were pre-assembled. I pressed them on with a setup similar to S.Ro's photo. The only kit that DID NOT WORK was the one supplied by you.

It's not rocket science. It's a pretty straightforward interference kit. It either stays put when you press them or it doesn't. When the tolerances aren't right or the material is inferior, the cap doesn't stay on.
Veni, Vidi, Posti
Neutrino MP3 492.7 AK, 2013 Moto Guzzi Norge
Joined: 29 Mar 2008
Posts: 21579
Location: Harriman, Tennessee, Tn
Sat Oct 26, 2019 3:06 pm quote
GotMojo wrote:
Motovista wrote:
That's because they are pressing the parts together for you, and eliminating one of the most difficult steps, so you're not trying to do it yourself without proper tools or experience. You do have to press the shaft straight down into the bushing for it to work properly, and that's almost impossible without a press.
You're way off base here. I have put together a few of these (and mangled a few in the process) so I know how it's supposed to be done. None of the kits I bought were pre-assembled. I pressed them on with a setup similar to S.Ro's photo. The only kit that DID NOT WORK was the one supplied by you.

It's not rocket science. It's a pretty straightforward interference kit. It either stays put when you press them or it doesn't. When the tolerances aren't right or the material is inferior, the cap doesn't stay on.
BINGO.
Veni, Vidi, Posti
MP3 500, GTS 250 (both 2008 MY), 2012 Honda NC700 DCT
Joined: 02 Mar 2013
Posts: 5911
Location: Madison, Wisconsin
Sat Oct 26, 2019 3:09 pm quote
Out of curiosity, what if the old shaft was at high limit of tolerance, and when the keyed drive was pressed on, it deformed (plastically). Then, when removed from the original shaft, and installed on the new shaft (presumably at low limit on diameter) there is no interference fit to press on?

Just curious.

Also, if this is the case, what about mashing the keyed piece in a vice or suchlike, to slightly deform it out of round, then press on the shaft?

Hooked
2009 250
Joined: 13 Oct 2019
Posts: 127
Location: Canada
Sat Oct 26, 2019 3:21 pm quote
Madison Sully wrote:
Out of curiosity, what if the old shaft was at high limit of tolerance, and when the keyed drive was pressed on, it deformed (plastically). Then, when removed from the original shaft, and installed on the new shaft
The kit I bought came with a new keyed drive. New on the left.
Enthusiast
GTS 300, BV250
Joined: 29 Jun 2018
Posts: 58
Location: Orange County, CA
Sat Oct 26, 2019 9:45 pm quote
Re: Water pump rebuid kit problem
Curiously enough, I had to revisit this tonight (unrelated to the OP's problem -- I'm rebuilding an engine).

I took a look at some of the shafts I had lying around and spotted something that might explain everything.

The shaft that has the darker metal is the "defective" one. The uniform gray-ish one is from the scooterwest kit. I had just removed it prior to replacing the bearings which is why it looks a little beat up.

Note 2 things:

1. The band at the end of the shaft looks like its prepared differently, almost as if its been ground down a hair

2. The end of the shaft has a hole in one and not the other. I suspect that the OEM tool peens the end of the shaft and widens it slightly. This would effectively lock it in place.

OK, 3 things...

3. They are CLEARLY different and were produced by different sources. Usually not a big deal if they're both 'OEM'. I betcha one is and the other isn't in my case.

I made sure that I gave it a good whack with a pointy punch after I pressed it all back together this time to be safe. It's nice and tight on this second go-around.

IMG_20191026_203422886.jpg

IMG_20191026_203436719.jpg

Veni, Vidi, Posti
Neutrino MP3 492.7 AK, 2013 Moto Guzzi Norge
Joined: 29 Mar 2008
Posts: 21579
Location: Harriman, Tennessee, Tn
Sun Oct 27, 2019 6:05 am quote
the one with the hole in the end is precision lathe ground versus the other is just bar stock cut.

So the OEM one will have better tighter tolerances than the cheap aftermarket bar stock one.
Hooked
2009 250
Joined: 13 Oct 2019
Posts: 127
Location: Canada
Sun Oct 27, 2019 7:11 am quote
I noticed the same things as GotMojo. No dimple on the end and darker colour with the "aftermarket" one.

The dead give away is the back of the impeller. If it doesn't have the Piaggio symbol and PA66 it's probably "aftermarket". Does the ScooterWest one have it?

Old as dirt is right. The dimple on the end is the mark from the holding tool when in a lathe.
Your Rally Here   vespa scooterwest scooter west Motorsport Scooters   Scooter Parts Company
Post Reply    Forum -> General Discussion
[ Time: 0.1762s ][ Queries: 27 (0.0407s) ][ Debug on ]