yz426 water pump shaft

[slopoke]

alright, well, i've got water dribbling out of the little hole on the bottom of the water pump casing...so far, i've searched and found that i think i need the two oil seals that go on the shaft?? do the shafts usually do ok?? i shouldn't need to replace it also will i???

[Hick]

alright, well, i've got water dribbling out of the little hole on the bottom of the water pump casing...so far, i've searched and found that i think i need the two oil seals that go on the shaft?? do the shafts usually do ok?? i shouldn't need to replace it also will i???

That depends.

If there is a big groove (usually by the outer seal, not sure why) then the new seals will wear out prematurely.

It is a judgement call, but if you see a deep groove in the shaft you can bet the new seals won't last very long.

I think a new shaft is in the high $20, low $30 range.

BTW...

If you are leaking water out the weep hole you may only need one seal, the outer one, in which case only the pump cover and impeller need to be removed. Make sure you install the seal facing in the proper direction (take a good look at the old one before you take it out).

Hope this helps.

[slopoke]

http://houseofmotorcycles.bikebandit.com/partsbandit/oem_schematic_view~schem_dept_id~850186~section_dept_id~1~section_dept_name~OEM+%28Stock%29+Parts~dept_type_id~2~model_dept_year~2002~model_dept_mfr~Yamaha~model_dept_id~845592~model_dept_name~YZ426FP.asp

so is that seal no. 5?

[Hick]

so is that seal no. 5?

No, #4.

The pic is slightly confusing, outer vs. inner. You just want to replace the one right behind the impeller (#2, #3 is a washer).

Seal #5 is the oil seal, or inner seal, which keeps the oil inside the cases, the outer seal keeps the water inside the pump, when water gets by it, it exits out the weep hole.

Hope this helps.

[slopoke]

icic, so at the very least i need seal no. 4 btw, what causes these to go out?? also, do i need to worry about antifreeze in my oil since that seal went out or, i guess that's seal #5's job correct?? thanks for all the help!!

[grayracer513]

If there is a big groove (usually by the outer seal, not sure why) then the new seals will wear out prematurely.

It's because coolant doesn't lube seals as well as oil does, and it isn't so much a matter of the seal installed on a grooved shaft wearing out early as it is of the seal being "trapped" by the groove so that the seal lip is unable to "follow" the shaft.

Otherwise, you're pretty much right, but I recommend replacing both seals, as they don't cost enough not to, and by the time you get the shaft out to inspect, you may as well.

Also, there is a machined groove in the shaft. That one belongs there. But you should easily enough be able to differentiate between that and one worn in by a seal.

[slopoke]

ok, going to order them tomorrow..hope they have them in stock....also...can i just unbolt the impeller from the shaft via taking off the water pump cover or do i have to take off the whole clutch cover?

[slopoke]

i meant the whole side cover, not just the little plate...just fyi..

[grayracer513]

If you try to remove the impeller from the outside just by cranking on the nut, you run the risk of damaging the drive tab on the shaft. With the cover off, you can use a pair of flats cut on the shaft to hold it with a wrench while you remove the impeller, and then you'll also be able to remove the shaft for inspection, and replacement of the inner seal, which isn't otherwise accessible.

[slopoke]

icic, thanks for the advice..i guess i'll just pull it all off...man..i just put new fluids in the bike!!!..grr...lol...also, the impeller isn't reverse threaded is it?

[grayracer513]

the impeller isn't reverse threaded is it?

not as far as I know.

[slopoke]

cool deal....thanks for all the advice!!!!