Cutless bearings - wear

[philmarks]

I've got a 40mm dia propshaft. I can move the shaft 0.5mm or so in the bearing. Is that excessive wear for this shaft size and should I change it now, or will it last me another couple of years? (I don't plan to haul out next winter).

Advice appreciated.
Rgds
Phil

 

[AndrewB]

This amount of wear would be regarded as excessive. Permitted tolerance is measured in hundreths of a mm - if you can move the shaft noticeably by hand, that is too much.

That having been said, there are plenty of boats about with this amount of play. You might take a chance on another season, provided there is no evidence of shaft vibration. But replacing the bearing is a DIY job on most boats and not expensive, so why take chances?

 

[david_bagshaw]

Is the movement loose movement or squashing the rubber?

If loose, it is time to change.


Good luck

David
<A target="_blank" HREF=http://www.euroboating.net>http://www.euroboating.net</A>

 

[airbubble]

2 % of the shaft diameter is the standard tolerance.

 

[philmarks]

Thanks everyone for advice. I make 2% of 40mm to be 0.8mm which would put me within tolerance. The play was without squashing the rubber.

On balance though, I guess it's time to get that hacksaw blade out.

Given that I've probably got excessive play in my back bearing (?) then I look forward to less noise in the aft cabin next year!

Thanks again

 

[Trevor_swfyc]

Phil,
I have fitted a new cutlass bearing at the end of last season so may I give you the benefit of my experience.
While I was removing the shaft to replace the volvo stern rubber packing box (stern seal) which was 14yrs old, original and due for replacing, volvo recommend 5 yrs life in use. So I decided it made sense to replace the cutlass bearing as well.
First remove the prop and shaft, then remove the cutlass bearing holder by removing the two securing bolts and unscrew anti clockwise ie counter to the prop rotation. Remove the two grub screws which hold the cutlass bearing in the holder.
You refer to using a hacksaw, I managed to remove mine without resorting to this by the use of a dowel rod just under the diameter of the external diameter of the cutlass bearing and driving the old cutlass out of the holder. When I purchased a new bearing I took the old bearing and holder to the helpful Volvo supplier, he measured the wear which was not uniform, it was eliptical also the rubber was clearly damaged probably by barnicles. I was told the new bearing would not be tight on the shaft and indeed should not be, it turns freely on the shalf and in use floats on the water (lubrication) between the shaft and cutlass bearing. The bearing also fitted easily into its holder and is held from any chance of turning by the two grub screws. I marked the cutlass bearing with a drill down the grub screw holes to ensure the grub screws held onto the bearing.
Hope some of the above helps.
All the best Trevor.