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Crank Seals


jandyb
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Hi again

Engine splitted and the old crank seals are out. At least the left one seems very bad so I guess it was on time to replace them.

But how the h***** get the new ones in place?? I have tried to drive them in using a socket, but they refuse to go straight in. I have also cooled the seals in the fridge for a couple of hours. Any Ideas?

-Jan

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Hi again

Engine splitted and the old crank seals are out. At least the left one seems very bad so I guess it was on time to replace them.

But how the h***** get the new ones in place?? I have tried to drive them in using a socket, but they refuse to go straight in. I have also cooled the seals in the fridge for a couple of hours. Any Ideas?

-Jan

Jan,

I usually put the bearings in a sealed plastic bag in the freezer for a while, add a little anti-seize on the bearing bore of the case and then lightly tap the bearing in about halfway with a smalll brass hammer and use a press to finish/seat it in the bore. I have a press with special attachments to push the bearing in square but I like to tap the bearing about halfway in with the hammer as it's easy to check that it's going in straight and easy to correct any misalignment as you go.

Jon

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Jan,

I usually put the bearings in a sealed plastic bag in the freezer for a while, add a little anti-seize on the bearing bore of the case and then lightly tap the bearing in about halfway with a smalll brass hammer and use a press to finish/seat it in the bore. I have a press with special attachments to push the bearing in square but I like to tap the bearing about halfway in with the hammer as it's easy to check that it's going in straight and easy to correct any misalignment as you go.

Jon

Hi jon

So You are online.. :-) Daytime in US now?

I am not replacing the bearings as they seem to be Ok. "Just" the seals.

Im beginning to wonder if I have got the wrong size as they refuse to go in. I`d never thought this shold be so difficult.. :-(

-Jan

Edited by JanDyb
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Hi jon

So You are online.. :-) Daytime in US now?

I am not replacing the bearings as they seem to be Ok. "Just" the seals.

Im beginning to wonder if I have got the wrong size as they refuse to go in. I`d never thought this shold be so difficult.. :-(

-Jan

It's about 5:30pm here.

Sorry, Jan, I misunderstood. Yea, you might want to check the parts number to be sure. As I remember, you have an 04" 300 and I've got the inner seals as #ME250112008 and the outer alternator seal as #MT280212009.

What I've done with seals is to get a long socket that just fits inside the seal and use a 10" extention in the socket so that, with the added length and leverage, it's a lot easier to keep the socket square to the bore when tapping it in.

Jon

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If you have it apart , it is a false ecconomy not to replace the bearings as well. I would do them even if nearlnew

lee

Point taken. You are of course right. And when at a closer look the clutch side bearing was beginning to "lug". Both bearings and all seals are changed now. I took the engine to a GasGas workshop, and the guy there was also very surprised that the seals were so tight, but after using way much more power than I dared to they finally came in.

One bearing question: on the flywheel side the bearing is supposed to be lubricated by oil through a "passsage", but the bearing and seal almost blocked that passage. Are there something to be aware of here?

-Jan

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One bearing question: on the flywheel side the bearing is supposed to be lubricated by oil through a "passsage", but the bearing and seal almost blocked that passage. Are there something to be aware of here?

-Jan

As long as there is a passageway, you should be fine. Ball bearings need very little oil (think about ones that only use what oil is in the premix) but they do not react well to contaminates. Bush type bearings (like in some four-strokes) tolerate contaminates to a greater degree as they embed in the bearing shell coating, but they require oil pressure to function.

This is why it's important to keep the transmission oil in the Pro clean and fresh by changing it often.

Jon

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