Rebuilding the LC4 Mechanical Water Pump - a Guide

Thanks for the excellent how to LC4 pilot, much appreciated.

I've now pulled my pump apart, and am replacing everything.

I've one quick question though, with the rubber seal that the shaft goes through, there is a bit of a recess on the inside that looks like it may be a good place to put some rubber friendly (red castrol) grease or some water proof grease, to lube the shaft that is spinning inside it. Has anyone done this? My shaft was a little bit worn in this area and was thinking some lube may have reduced this wear?

Cheers

S

the shaft wears out eventually,,,after about 4 rebuilds..

Sean, I'm glad you found the article helpful. I just put a light coating of motor oil on the shaft, mainly to help the shaft seat in the rubber seal properly. It's a tight fit, so it's easy to accidentally have the edges of the rubber seal not sit properly by being pushed outward from the insertion of the shaft.

Sorry if that sounds "dirty," but I don't know how else to word it!

If your shaft is significantly worn, you may consider replacing that too, since I don't know if a coating of oil will be sufficient to seal it.

Good luck!

There's enough room in there for a little grease, as well as the surface isn't totally flat, it's a little concave on the inside.

I'll have a think about it, I may put some grease in there.

Cheers

S

About to put it all together again tonight.

Still not 100% sure on the loctite to use for the seal, I've bought the 603, only worried it mightn't hold up under heat as well as the 648, but I'm not going to fork out $50 for a bottle just to use 3-4 drops!!

Also found NTN bearings, part#: 6001 LLUC3/2AS which are cheap.

If anyone has anything against NTN bearings please let me know and i'll buy some SKF ones instead.

Cheers

S

http://www.amazon.com/Loctite-648-Retaining-Compound-Bottle/dp/B0016KU6MU

$11.43 @ Amazon for the little bottle.

I just noticed that you're "Down Under"...so I guess Amazon is out. sorry.

Cheers, yes down in Oz.

I'm going to go with the 609 (not the 603 as stated above), I've cleaned the housing up with petrol and then acetone and rags. I'll coat the seal outside surface with the 609 and press it in in a bit. I'll then give it around 24hrs to cure before I put the shaft and bearings in.

S

Okay, I manged to get the WP off the bike and all of the various and sundry parts of the WP have been removed...but I'm having trouble getting the shaft driven thru the seal. I've destroyed two seals (one of which I spent three hours driving down and back this afternoon to pickup from the closest KTM dealer)...so obviously I'm doing something wrong.

I just placed the order for two more seals, as the "local" dealer won't be open Monday, and I'm pretty sure they said they only had the one seal in stock.

So, any additional hints or tips on installing the "shaft" thru the seal...more lubricant, more cowbell, more ???

Has anyone tried installing the seal on the shaft and then installing the entire assembly into the housing? I can force the seal on the shaft, but that seal is a bit wacked (one of the retaining springs, keeps falling out) so I'm going to have to wait until next weekend to play with an undamaged seal.

FWIW, I'm using a new shaft and the edge of he shaft seems too sharp, I might try to put a very, very slight chamfer and see if that helps it "slip in".

Pictures for those who might be interested...

Yes, there was an inmate that first installed the seal on the shaft and then successfully pressed it in....

What are you using to press the bearings/shaft into the housing?

I pushed the shaft in by hand, with some lube. It was real tight , after it was assembled I could barely turn the shaft by hand. No wonder they wear out.

Probably if you put the assembled bearing/shaft/seal combo and threw it in the freezer overnight and then warmed the pump body it would slide in with little force....

That's what I'm going to try (once I get the new seals). Use a heat gun to warm up the housing and perhaps get a bit of dry ice to chill the shaft/bearing/seal assembly.

I was using a rubber mallet and a 17mm 1/2" drive Craftsman socket to motivate the shaft assembly into the housing. I've been wanting to get a small press, perhaps I'll stop by HF after church and see what they've got in stock.

I would install the shaft, and then finding it too hard to rotate, thus I would pop it back out and reinstall the shaft. I finally noticed that the circle spring from one side of the seal sitting meekly on the floor. That was the second seal, the last I had in my possession, so I gave up for the night and went to whine on the internet.

Like dhally said, the shaft is very hard to turn when the pump is assembled... The 2 lip seals create quite a bit of drag....

The original pump didn't feel all that difficult to spin, but it was seeping slightly, so I suppose the seal was shot.

I did pickup the small arbor press at HF this afternoon, and will try installing the seal and shaft as an assembly. I shall report back once it's back together (hopefully this week sometime).

M.

Today I discovered this leak, well very small leak.


Coolant looks clean, oil looks fine. I guess just one side leaks? I had it on my bmw F 650, except that it leaked a lot. Anyhow, it took almost 10 years and 22 kmiles to get it leaking.

It's your lucky day as the leak in your picture looks to be coming from the thermostat seal which only requires removal of the 2 Allen screws in the picture and a replacement O-ring to fix...

Cool. I spend about an hour trying to understand how water pump seal failure can cause this leak.
On other bikes it's designed to show that the water pump seal is busted.

Yeah, that leak is a long ways from the water pump.... If you look on the opposite side of the cylinder head you will see where the plumbing connects into the pump/impeller housing....

666,
Still you better do the pump this winter. You are at the time and mileage where it can't be trusted. Neither can the cam followers. Rebuild time for you. IMHO. Gunner knows more. I just did mine for the third time at 37K miles. One seal was leaking, the bearings were solid. I pop the bearing seals and add extra grease when I rebuild. I never loctited a shaft seal, in fact I grease them to get them to go in and grease the lips. Greasy lips on the shaft....
bill

What winter? We don't have it here.

I have parts on hand and would do rebuild sometimes in the near future.
My former bmw blew 5 sets of seals in 20 k miles. All done under warranty, really annoying.