hopefully last jet pump rebuild!

[sea~smith]

So all my parts for the jet pump have arrived! Big thank you to 97sltx1050 for being my middle man and shipping the stuff over to Canada (saved me 30 bucks!). I figured I would post some pictures of my jet pump rebuild - I also have a few questions.

I have the parts laid out in the order I think they go, but I am not sure where that o-ring on the bottom of the picture goes? The manual isnt being much help either. The rebuild kit was a wsm for all models 94-00 so I have the right kit. I also put the seals back to back with springs facing outwards (correct me if im wrong). There is also an o-ring I already put on that is at the cone end, it might be a bit hard to see but it is on there.

Does the seal collar always rub up against the bearing race? When I first took appart this pump, the seal collar had actually fused itself to the bearing...is the mystery o-ring supposed to go in between the seal collar and bearing?

I didint bother including the cone o-ring because i know where that goes.

Thanks for your help, this pump has been rebuild 3-4 times now from what i hear, so i really want to make sure this is the last time.

[xlint89]

Does this help? http://partsland.com/index.cgi?N=120...650-PROPULSION

[sea~smith]

its as if they are missing some o-rings... in that diagram, like the manual, 15 and 16 are there, and I know where they go. There is another o-ring which I am pretty sure goes on the opposite end of the stubshaft, but i cant figure out where that bigger o-ring goes?..

[sea~smith]

today I put the bearings in the stator, along with the spacer. The bearings went in so that the spacer could no longer move at all, in fact it is really jammed in there - is that normal? I used the socket on the outter race to hammer it in there, and i used a rubber mallet. Once they were in, I could put the stub shaft in with a little pushing, but I could not put the alignment tool in very well at all, it just wasnt going through.

This stator has had some history, I think this might be the 4th or 5th time it has been rebuilt, what do you guys think, just pitch it and get a new one from john ziggler? Its a very frustrating thing to have to replace a stator because it is out of round, mainly because it can be so hard to prove...

[K447]

today I put the bearings in the stator, along with the spacer...I used the socket on the outer race to hammer it in there, and i used a rubber mallet...

For future reference, a suggested technique is to use temperature differences to allow the bearings to fit in without a lot of force being applied.

With the stub shaft inserted into the bearings, give the stub shaft a modest tap on the impeller end, before attaching the impeller. The tap can help ensure the bearings are aligned with the shaft.

[K447]

...The bearings went in so that the spacer could no longer move at all, in fact it is really jammed in there - is that normal?

Others will know for use, but my guess is that the tight spacer is putting side pressure on the bearings, which may shorten their lives.

You may have found a contributing factor to the previous bearing failures. If the bearing spacer is slightly too long, or the stator bearing support faces are too close to each other, then the bearings might have had unwanted side loads since new, and after each rebuild.

Unless those bearings are designed to handle side loads from the spacer side, they will not have happy lives.

I don't think you can accurately measure the spacer length or the bearing face-face gap with the bearings installed, and I do not know exactly what those measurements should be. Perhaps others will be able to shed some light on the tight spacer question?

[xlint89]

The internal spacer should not be tight. Mine will have some side to side movement with the bearings properly seated.

[beerdart]

Measure spacer length with a Vernier caliper.
Replace if worn beyond service limit. If the spacer
is too short, the bearings will be side loaded and
premature wear will result.

[sea~smith]

I think we might be on to something.. I measured the spacer I bought from babbits, and it was between 43 and 44 mm long. The odd thing is, when I hold the spacer in the stator where it would usually go, its LONGER than the distance from bearing seat to bearing seat by about a mm each side. This seems very strange to me, since it means the bearings will never seat, and they will squish the spacer as I did the first time round. This is very likely the reoccuring problem with this pump! Here is my thinking:

1. same spacer (which is too long) has been used each rebuild

2. When attempting to seat bearings, the bearing hits the spacer prematurely and never really seats, exept on the inner race

3. By continuing to whack at the bearing outer race with a socket, you are really destroying the bearing by putting a huge load on the inner race each time you hit it because of the excessive length of the spacer

4. The stub shaft can be forced in, but the alignment tool tells a different story, as it wont go through both bearings!

The only way my line of thinking fails, is if the bearings are NOT supposed to seat on the outer race, but instead on the inner race. I dont find that logical... Why would the bearings seat on a spacer, it just doesn't make sense.

[beerdart]

The spacer seats on the inner race when the impeller is torqued. If the spacer is to long or short you are distorting the inner race.