Question on carbon seal

[100dollarbill]

Does a new carbon seal fit snugly on the driveshaft or is there supposed to be some play in it?
The hole in my seal is bigger than the diameter of the shaft and so is the one I got with the used driveshaft I ordered online.
I'm trying to resolve my high rev and little thrust problem. (wear rings are brand new)

 

[BoLongo]

The carbon seal is not supposed to touch the shaft. If your engine is out of alignment, you can get a wobble that can egg shape the inside of the seal from making contact with the shaft. Check your bellow (the accordion boot); it should be flexible, not hard or cracking. A little trick for added pressure between the carbon seal and the hat (the metal piece that rides against the seal) is to slide the bellow forward about a 1/4 inch and tighten up the rear clamp.

 

[100dollarbill]

Ok got ya. So when they talk about air leak around carbon seal causing cavitation, where is it getting in? A bad bellows or a gap between the carbon seal and the hat?

 

[BoLongo]

Yes, it is usually between the carbon seal and the hat. If it is really bad, it will let water in the bilge.
The pump suction is so strong; it can pull air from between the carbon seal and the hat; even if it is not leaking water.
You also have a couple of o-rings inside the hat that prevents water from leaking between the shaft and the hat.

 

[100dollarbill]

Thanks Bo. It makes sense now.
One more question... Is there any way to test if the carbon seal is bad or do you just replace it? And just the carbon seal ($30) vs. the driveline repair kit ($85 seal, bellows, hat, etc.) OK that was 2 questions.:willy_nilly:

I'm going to try the bellows adjustment you mentioned.

 

[100dollarbill]

I just saw you're edit. I don't recall seeing those O rings on mine. Are they in the hat or are mine missing??

 

[BoLongo]

If the bellow is hard or cracked, get the kit. If it still looks kind of new just replace the seal.

You have to look inside the hat to see the two o-rings

 

[100dollarbill]

Bellow looks good, I'll get the seal.

 

[Coastiejoe]

You can go for a run with the seat off and watch the CS area. A drip is fine. A stream is not.

If you do the slide the bellows trick, put a zip tie behind it in the gap you just made. This will help to prevent the bellows from sliding back into place.

 

[BoLongo]

I like the zip tie tip; I will be using that one in the morning. :thumbsup:

 

[100dollarbill]

You can go for a run with the seat off and watch the CS area. A drip is fine. A stream is not.

I'll just open the hood. (it's a speedster):cheers:
And thanks for the ziptie tip. I'll definitely do that.

 

[BoLongo]

You also want to clean up the surface on the hat that rides against the carbon seal. Get a piece of 1200 grit sandpaper and lay it on a smooth flat surface. Slide the hat in a circular motion until the surface looks clean.