'95 GTX impeller bearing replacement (was: how to static test?)

[Normallysailing]

Finally got a chance to start pulling it apart. Didn't take long to find a handful of nastiness under the impeller cover. Looks to me like it ate the thrust bearing, which would be consistent with observation: That it made an evil noise while pushing water but didn't sound bad while testing on dry land.

Now, does the whole impeller housing have to come out in order for me to do this repair? Looking at the exploded diagram it appears I should just be able to unscrew the impeller shaft (with the housing in place) and replace the bearing(s). I can't see how it attaches to the drive shaft, though. Do the two just screw together? Is there a wrenching flat or similar on the driveshaft that I hold in order to unscrew the impeller shaft? And if so, it it a left- or right-hand thread?

Or is my thinking about how to tackle this totally wrong?

 

[artr]

There are probably detailed instructions in the shop manual for your model but basically you need to remove any reversing and steering mechanisms from the rear of the pump then remove the pump from the ski (should pull off and leave drive shaft behind), remove nose cone and drain pump oil, get an impeller removal tool to slide into impeller and place pump in a vise to hold the flat end of the impeller shaft that is under the nose cone, use a long wrench or breaker bar to spin off the impeller. I think it is a normal thread but if in doubt, the engine spins the impeller in the direction to tighten it on the shaft. It may be difficult to get it off because of loctite that is specified between the impeller and shaft. You can heat up the impeller to help break that seal. Once the impeller is removed the shaft can be pulled out and bearings can be inspected and replaced if necessary. The thrust bearing and washer come out with the shaft and are simple to replace. I have not replaced the the other bearing yet or the pump seal but there are description in the shop manual and posts on the forum to do it without special tools.

 

[Normallysailing]

Hmm. So it isn't done in situ - the whole impeller assembly has to come off first. I'm as far as having taken off the nose cone - that's where I found the remains of (what I presume is) the thrust bearing, and no lube. If I'm reading you right, the drive shaft just seats into the impeller from the front, and the impeller shaft screws into the impeller from behind. I just googled the impeller removal tool, and it's just a splined bolt, so that must be how the drive shaft and impeller are coupled. Do I have that right now?

 

[artr]

Yes. Unfortunately, if there was no jet pump oil in the nose cone chances are that the other 2 roller bearing might have been damaged. I think you need to pull the pump apart and do a thorough inspection of the shaft, seals and bearings.

 

[Normallysailing]

That looks like what happened - it was run dry. I'm new to these things (got this and an SPI a couple of years ago), and they haven't seen too much use. So I'm still getting up to speed on details like this.

When I pulled the nose cone, it was just full of bearing bits, carbon dust and chunks, and bad smell. I assume that post-assembly it's filled through that setscrew hole.

 

[artr]

That is correct

 

[Normallysailing]

I was hoping that after pulling those four 17mm nuts holding it in place, the pump would pretty much fall off. Not quite so lucky - looks like some PO aggressively RTVed it in place (unless there's something else holding it on that I haven't spotted?). Can anyone offer any suggestions for separating it with minimal damage?

 

[artr]

I once used a silicon sealant instead of the neoprene seal and that was a mistake. To get the pump off I used a pry bar with a L shaped tip to get under each of the for tabs on the pump that the 17mm bolts go on. you could also use the claw of a normal hammer if you can fit it in the tight space. You need to be careful especially if the pump body is plastic not to break the tab. I remember trying to get the pump to rock a little while applying pressure with the pry bar until the sealant eventually broke loose in each area.

 

[POPPS]

So,,,make sure the venturi is on,,,then get 2 long pry bars,,,if there are 2 of you,,,otherwise I will use the top of the hull to pry the top edge of the venturi,,,and then i go below the venturi,,,usually gets the job done,,

 

[Normallysailing]

Getting in there anywhere to pry looks like a real challenge, especially with the shoe in the way. And I'm terrified of prying either the impeller housing or the venturi for fear of breaking bits off. I feel like I need some kind of pry bar with a right-angle point just to try to get at where the impeller housing meets the hull.

 

[POPPS]

Please post a pic,,,trust me,,,i have hadnthe older style pumps sealed with rtv,,and i thot i will not get them off,,but i do with a pry bar,,working alternatively,,,top of the venturi,,,bottom of the venturi,,,

 

[Normallysailing]

Man, did that ever SUCK, and if I ever find the guy who did it, there's going to be a 'nad-kicking for the Guinness book. I got it off. The (black automotive) RTV was glopped all around the water outlet tubes, and that other tube that connects to the three holes inside the pump body - I assume those feed back to a pressure sensor or something - no, wait, it looks like it has something to do with the cooling system, but I really don't get what's what with all that plumbing. Is there a guide somewhere that explains the flow path? Anyway, what's just described as a "fitting" came away with the pump, and I strongly suspect it should have stayed with the hull, so I'm going to keep cleaning this crap off and try to seal all these tubes properly once I've gotten my bearing kit and tool and done the thing I came to do.

 

[Normallysailing]

Followup: I see now that the "fitting" screws into the impeller body - but it had been broken off and RTVed back together. Now that I've extracted the broken end, is that part (293 700 019) still available?

[edit]

Yeah, looks like it. Hoping I can catch my order for the bearings+tool and get this added to it.

 

[POPPS]

I have the pump..if you can't find the part,,the intake cooling fitting,,,i believe it is an npt thread that you can buy at diy and plumbing stores

 

[etemplet]

That part can be ordered. He's gonna have to rebuild the whole pump if the pump housing isn't seriously damaged. Probably gonna need a new pump shaft as well. $120 for parts I think and he'll need to tools to install the bearings. Good Luck

 

[Normallysailing]

I think my girls caught it quickly enough (they're learning!) that the pump housing wasn't damaged. Hoping I don't need a new shaft, because it really is turning out to be difficult to get parts for these things. Once I get the impeller/shaft tool I'll be able to see what I'm up against.

Until then, I just got my Mikuni rebuild kit today, so it's off to work on the SPI while I wait for the GTX stuff!

 

[mikidymac]

If you found the "remains" of the bearings an no lube the shaft and all bearings inside are trash. Just rebuild it and be good to go.

 

[Normallysailing]

At the moment, the only thing that's not clear from the diagrams is the three coolant hoses that pass through the hull. There's so much RTV to be cleaned out that I really can't see how the hard inlet tube threaded into the pump housing engages the line in the hull. Same with the pair of outlet tubes. Raining now, but once I can get outside and continue the cleanup I'll try to figure out how all these lines are supposed to seal without a (literal) mess of RTV.

 

[Normallysailing]

If you found the "remains" of the bearings an no lube the shaft and all bearings inside are trash. Just rebuild it and be good to go.

So far, just those of the thrust bearing, I think. I'm hoping the two needle bearings aren't blown out enough to have damaged the shaft, but I've gotta wait for the tool to find out.

 

[Normallysailing]

The kit (and tool) came in. Now I just have to disassemble this thing. I'm a-pullin' and it's not a-turnin'. How much torque am I going to have to apply to get the impeller off of the shaft? Is this a job for an impact driver? First timer, so I'm a little nervous, of course.

 

[mikidymac]

Put the impeller shaft in a vice, heat the impeller with a propane torch and use a breaker bar with a cheater bar to unscrew the impeller off the shaft. It has normal threads.

An impact typically will not work and could damage the splines.

 

[Normallysailing]

Thanks. I'm pretty much strapped for cranking stuff like this - a 3/4" ratcheting breaker bar is usually pretty convincing. Will get it toasty and give it another go.

 

[Normallysailing]

That was easy. Looks like this shaft is trashed, though, and in quite a weird way. There's a deep groove just behind the shaft's head that has the thrust washer trapped in it - the two pieces look like an impossible assembly. I guess what happened is that the blown-out thrust bearing and washer cut the groove in the shaft, then the washer flattened/deformed inward into the groove (the bearing is totally vanished, of course). Very odd.

 

[Normallysailing]

Waitaminute... I'm looking at a picture of the shaft here:

Jet Pump Impeller Shaft - Seadoo 580-800cc

and it appears the groove is supposed to be there. Obviously the washer has been deformed and shouldn't be trapped in it, so it'll have to be cut/ground off. I thought the groove looked too clean to have just been carved by spinning trash. But with that groove, how do the bearing and washer stay centered?

 

[Normallysailing]

Mmmm... on third thought, I think the shaft is done for. The face of the shaft that the thrust bearing contacts isn't flat anymore - it's worn/bent/deformed convex, and the thrust washer conforms to it. So I'm in for a replacement shaft after all.