Very stiff cutlass bearing

[GHA]

A short tale of woe and red herrings..

Previously.....
After much gnashing of teeth getting the old cutlass bearing out - steel long keel hull, so bearing goes into a short piece of pipe against a shoulder then the pipe continues for about 3' to where the stuffing box is attached.

So, tapped the new cutlass bearing in and then tried to insert the prop shaft, gets very stiff quickly. So ever the pessimist I concluded it was catching on corrosion in the longer section of the pipe. Managed to get the new cutlass bearing back out and welded up a grinding stone on a 3' piece of rod to clean up the inside of the pipe.

Turns out the stiffness was nothing to do with that, the bearing will slide up and down the propshaft easily on it's own but once fitted the shaft become very stiff, as in barely possible turn it by hand.

Is this normal? Will it bed itself in quickly when running or do I need to ream out a tiny bit of the inside of the cutlass bearing?

It's a tight fit into the stern tube but it does go, not sure if i want to take off too much of the outside of the bearing, but maybe a bit.

Tia.

 

[Heckler]

A short tale of woe and red herrings..

Previously.....
After much gnashing of teeth getting the old cutlass bearing out - steel long keel hull, so bearing goes into a short piece of pipe against a shoulder then the pipe continues for about 3' to where the stuffing box is attached.

So, tapped the new cutlass bearing in and then tried to insert the prop shaft, gets very stiff quickly. So ever the pessimist I concluded it was catching on corrosion in the longer section of the pipe. Managed to get the new cutlass bearing back out and welded up a grinding stone on a 3' piece of rod to clean up the inside of the pipe.

Turns out the stiffness was nothing to do with that, the bearing will slide up and down the propshaft easily on it's own but once fitted the shaft become very stiff, as in barely possible turn it by hand.

Is this normal? Will it bed itself in quickly when running or do I need to ream out a tiny bit of the inside of the cutlass bearing?

It's a tight fit into the stern tube but it does go, not sure if i want to take off too much of the outside of the bearing, but maybe a bit.

Tia.

Dont dress the outside of the bearing. If necessary do the ID. Check that the shaft is square to both the CB and the Stuffing Box. If it is OK dress the ID. Bit of sand paper on a rod, something along those lines. Be careful of using emery in case it leaves bits in the CB. Although I have used that before now!
S
PS both my Benes had rubber CBs Even new they have half a mill clearance

 

[vyv_cox]

I assume you have tried it wet? A dry cutless bearing has very high friction against a shaft. Try water with some detergent.

 

[MoodySabre]

Two stories here.
The bearing slides on the propshaft OK - well it does need to be a cosy fit so why take anything off the inside of it?

When the bearing is pushed in the stern tube then the bearing gets very tight on the propshaft - do you need to take something off the stern tube? It sounds as if the stern tube is distorting the bearing but surely it would only do that if a lot of pressure was applied (thought, is it a brass/rubber bearing?). To squash a bearing slightly oval would take a lot of effort if it is a brass shell.

Was the bearing worn unevenly? Perhaps it doesn't all line up very well.

What to do? well messing about with the bearing is cheaper than altering a stern tube which has worked OK so far. If you can turn the propshaft a bit then I'd be inclined to leave it and let the engine effort wear the bearing down a bit. I know that's not ideal.

 

[scottie]

Check the sizes and look out for imperial and metric mixes

 

[GHA]

I assume you have tried it wet? A dry cutless bearing has very high friction against a shaft. Try water with some detergent.

Oh but I can be so very stupid sometimes

Though even with fairy liquid it still seems very stiff, though not uniform up and down the shaft. Brand new shaft from t norris and bearing from ASAP.

 

[GHA]

Check the sizes and look out for imperial and metric mixes

Both metric, brand new.

 

[GrahamM376]

Is this normal? Will it bed itself in quickly when running or do I need to ream out a tiny bit of the inside of the cutlass bearing?

I would say leave the cutless bearing alone and look for a high spot in the stern tube where it fits, it sounds like the bearing is getting distorted by something. Presumably, there isn't another bearing just behind the stern gland and the two don't line up?