Fasteddy, would you mind clarifying the orientation you used for the seals? Hard to tell from the pics.Water pump seals
After some delays I have finished rebuilding my water pump. I ended up using two different types of seals and from all that I have learned about rotary shaft seals I would not use the OEM seals.
The original seal used, part number J760122455, is a single lip seal made form something that is meant to be some type of rubber, I assume.
I had hoped to acquire a PTFE Teflon double lip double spring seal, this is the type of seal used in the LC8 water pump and one with correct dimensions was used in the race version RC250 - R Rookie Cup engine in 2013 / 2014, part number 0760122407 SHAFT SEAL RING 12X24X7 PTFE, but unfortunately that part is not available from KTM and I was unable to source one from anywhere else.
I was able to find a much better seal that is used in KTM 450 XC water pump and many others, part number 77335057000 SHAFT SEAL RING 12x24x4 which is readily available. I also sourced a couple of Fluorocarbon / FPM material seals with stainless steel spring from www.123bearing.com part number OAS-12X24X7-FPMSS.
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left - OEM, middle - 450XC, right - FPM
The OEM seals have a noticeable difference in texture from the Viton 450 XC seal, the quality became obvious when I tore the pump down. The outer seal looked to be in good shape but coolant had filled the bore past the seal, after removing the lock ring I was quite surprised that I was able to remove the seal just by grabbing the outer edge with a pair of needle nose pliers and giving it a tug. It was obvious not only had coolant been getting past the lip but also past the bore and seal.
I then removed the crankcase seal through the bore with the drill and screw method, it too came out with surprising ease.
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So I debated on different ways to use he 15mm of bore depth, two XC seals doubled up on the pump side, replace the OEM with the thicker FPM, in the end I chose to use the XC seal for the crankcase side and an FPM seal for the pump side. One of the things to consider was where the seal would land on the wear bushing. I used clear silicone grease to on the seal lip surface and the shaft and a light film of RTV on the outside of the seals. The crankcase side went in as expected with more resistance then the OEM had coming out. The pump side had resistance form air trapped in the bore and pushed back out (needs weep hole), I took my time and slowly got it in and the lock ring installed.
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The weep hole looks like it could be added but It would be nice to have a measurement of how much material is behind the pump face. This would need to be measured from the inside of the case, If anyone has a case split apart I would be interested in a PM ...
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note: if you remove the coolant pipe from the pump housing you will want to put in a new "J770018530 - O-RING 18,5X3" that does not come with the pump kit.
Water pump and/or linkage failure
- Thread starter streetfighter
- Start date
Fasteddy, would you mind clarifying the orientation you used for the seals? Hard to tell from the pics.
Fasteddy
Member
The flat face of the seal goes away from pressure, so the flat faces go against each other, inner seal flat face towards outside, outer seal flat face toward inside of motor...
Thanks! I have a variety of seals on hand (the OEM water pump kit and a few extras) including the 450 XC seals which I had planned to use based on your / other's successes. As was noted above the 450 XC seals are not as thick as the OEM units. I'm assuming the best move is locate the seals at the extreme ends of the bore so they are as far away from one another as possible (the inner seal with the rear face pressed against the inner housing, and the outer one with the rear face against the retaining clip). Would you agree?
Fasteddy
Member
Yes, I would agree. I have another RC390 that I have the XC450 seals in and no issues...
I would not use the OEM part number 901.... seals.
Roger that and thanks for confirming. My part number for the 450 XC seals is 77335057000. Agree on the weep hole concept too. If anyone trashes a right side cover and can spare it for science, would be good to see how to add one without impingement into an adjacent cavity.
Circling back on this.
This particular example (2020 390 adventure) had a low oil pressure warning light going off.
Drained the oil and found several ounces of coolant. Refilled oil. Tested oil pressure at the filter housing. 30+ psi at idle.
Replaced both seals as detailed and discussed above. No retaining clip on this particular bike. Didn't even see a groove for one cut in the bore.
Outer seal found to be installed correctly, inner seal was installed incorrectly, I think. It's almost like it's a 2 sided seal (it was also falling apart).
Installed the new 450 seals with the rears facing the fluid filled systems (oil and coolant respectively).
Refill the bike with coolant. Test ride followed.
The bike was still exhibiting a low oil pressure warning light.
Next step. Dump the oil and look for evidence of coolant... negative.
Next, pull the oil pressure sensor at the head. Check for pressure while running with a mechanical gauge. Gauge reads zero (remember it had oil pressure at the filter housing when tested via the factory method).
Hmm.. what if we remove the oil filter and test for pressure again at the head???
Voila!! 30 psi at the head!! YES!!
Filter autopsy time.. cut the pleats off.. filter media is greenish and squishy... Hmm. Coolant?? Likely.
Dump oil. Install a new filter. Refill oil.
Test pressure at the head again.. still 30+ psi at idle. More like 45psi at 5k rpm.
Long story short, the filter being wet with coolant blocks flow completely.
Now to my scolding of the engineers.. this wouldn't happen if the filter had a bypass..
Silver lining. We wouldn't have discovered this if the filter had a bypass.
Next steps.
1) Ride testing to verify integrity.
2) Find a filter the same size with a bypass.
3) Tell everyone I know with a KTM 390 to do this retrofit
This particular example (2020 390 adventure) had a low oil pressure warning light going off.
Drained the oil and found several ounces of coolant. Refilled oil. Tested oil pressure at the filter housing. 30+ psi at idle.
Replaced both seals as detailed and discussed above. No retaining clip on this particular bike. Didn't even see a groove for one cut in the bore.
Outer seal found to be installed correctly, inner seal was installed incorrectly, I think. It's almost like it's a 2 sided seal (it was also falling apart).
Installed the new 450 seals with the rears facing the fluid filled systems (oil and coolant respectively).
Refill the bike with coolant. Test ride followed.
The bike was still exhibiting a low oil pressure warning light.
Next step. Dump the oil and look for evidence of coolant... negative.
Next, pull the oil pressure sensor at the head. Check for pressure while running with a mechanical gauge. Gauge reads zero (remember it had oil pressure at the filter housing when tested via the factory method).
Hmm.. what if we remove the oil filter and test for pressure again at the head???
Voila!! 30 psi at the head!! YES!!
Filter autopsy time.. cut the pleats off.. filter media is greenish and squishy... Hmm. Coolant?? Likely.
Dump oil. Install a new filter. Refill oil.
Test pressure at the head again.. still 30+ psi at idle. More like 45psi at 5k rpm.
Long story short, the filter being wet with coolant blocks flow completely.
Now to my scolding of the engineers.. this wouldn't happen if the filter had a bypass..
Silver lining. We wouldn't have discovered this if the filter had a bypass.
Next steps.
1) Ride testing to verify integrity.
2) Find a filter the same size with a bypass.
3) Tell everyone I know with a KTM 390 to do this retrofit
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