Replacing cutlass bearing

[carpediem32]

Is it possible to replace the bearing without removing the propshaft? The shaft on my boat will not pass the skeg and I would like to avoid having to shift the engine forward to do this. I wondered if the bearing would turn on the shaft if it was tapped lightly, after releasing the grub screw. Any ideas?

 

[Tranona]

Is it possible to replace the bearing without removing the propshaft? The shaft on my boat will not pass the skeg and I would like to avoid having to shift the engine forward to do this. I wondered if the bearing would turn on the shaft if it was tapped lightly, after releasing the grub screw. Any ideas?

Not usually. The bearings is a press fit in the housing. The grub screw just ensures it won't move. Has to be pressed or cut out which means removing the shaft.

 

[Suttle]

+1
Very unlikely you will be able to move it without removing the shaft. Are you sure you cannot get your shaft past the skeg. I have a skeg and there is just enough play to get the shaft past skeg.

 

[GrahamM376]

Depends on how your cutless bearing is mounted. If it's in a P bracket then it may be possible to knock it out using a split tube, depends how tight a fit it is. Unfortunately, some P brackets like ours have a lip at one end so, our shaft has to come out.

 

[Norman_E]

Not usually. The bearings is a press fit in the housing. The grub screw just ensures it won't move. Has to be pressed or cut out which means removing the shaft.

No it does not, if the yacht has a skeg. You need to make a split tube extractor to push the bearing out after removing the prop from the shaft. I have posted this picture of the parts of mine before to show what is required. All parts are there, including two different split tubes. The only other parts needed are two lengths of 10mm studding.

 

[Suttle]

That wont work on mine as I have a skeg but not a P bracket, mine is fixed to the deadwood. You have to remove the shaft to get the bearing out.

 

[Westerly Jetstream]

I changed mine last yr (fixed to deadwood) without removing shaft as shaft couldn't come past skeg and I was NOT taking engine out.

Mine was in a housing secured to deadwood by two bolts I removed prop undid bolts slid housing cw cutlass down shaft retired to workshop, removed and replaced cutlass and then reversed process.

 

[alahol2]

I changed mine last yr (fixed to deadwood) without removing shaft as shaft couldn't come past skeg and I was NOT taking engine out.

Mine was in a housing secured to deadwood by two bolts I removed prop undid bolts slid housing cw cutlass down shaft retired to workshop, removed and replaced cutlass and then reversed process.

Ditto, except had to hold stern tube inside boat whilst cutless carrier was unscrewed from it outside.

 

[Westerly Jetstream]

Yes ditto three long extensions on ratchet with socket, but this yr I've discovered tube original from early 70s is porus so whole lot has to come out and be replaced with GRP

 

[Mistroma]

Ditto, except had to hold stern tube inside boat whilst cutless carrier was unscrewed from it outside.

Same arrangement on my old Southerly 95 and quite an easy job to remove the tube and cutless bearing. Much easier to push the bearing out of the tube in the garage at home. It was quicker to remove and replace using 2 people as the nuts inside the hull weren't captive.

Removing the prop. proved to be easy using a puller, some heat and a light side tap with a hammer.

 

[Tranona]

No it does not, if the yacht has a skeg. You need to make a split tube extractor to push the bearing out after removing the prop from the shaft. I have posted this picture of the parts of mine before to show what is required. All parts are there, including two different split tubes. The only other parts needed are two lengths of 10mm studding.

That will not always work. It depends on the boat and the number you can do this with is small. That is why I said usually.

 

[Neil_Y]

Depends on the type of bearing and the type of fit (clearance or interference) possible but difficult.

We like our bearings fitted on epoxy so installing with the shaft in place is difficult as it's best to coat the bearing carrier with epoxy when you install, removal is easier as the epoxy softens with heat.

 

[charles_reed]

Depends on the type of bearing and the type of fit (clearance or interference) possible but difficult.

We like our bearings fitted on epoxy so installing with the shaft in place is difficult as it's best to coat the bearing carrier with epoxy when you install, removal is easier as the epoxy softens with heat.

I've heard of people using silicon sealant to fix the cutless in the housing but never epoxy!!

I'd be surprised indeed if the shaft didn't come out, with a clearance fit to the skeg, on the OP's boat. In my case it's the rudder that's in the way - it's easier to take the latter off than try anything else. Using a split removal tool is the ideal way to do it with a P-bracket but, as I understand it, the cutless bearing is in the deadwood (as is mine).

 

[Neil_Y]

I've heard of people using silicon sealant to fix the cutless in the housing but never epoxy!!

Epoxy is widely used on commercial and military vessels for Maritex bearings.There are a number of advantages not least of which is that no tools are required for install or changing. Epoxy in a thin layer doesn't actually bond but supports the bearing against what can be a rough uneven surface, it also prevents salt water pockets giving rise to corrosion (particularly bad on Al carriers). Using a low melting point type such as 2011 means it softens with heat for removal.
Press fit risks squeezing the bearing to the point that bore closure means the clearances are too small, with a clearance fit you know the ID will be unchanged after fitting. I've never heard of anyone using silicone but it doesn't surprise me, The problem is the side loads on a bearing in a soft material will cause it to move, seeing as the bearings are there to hold the shaft in a straight line this can't help much.

 

[charles_reed]

Epoxy is widely used on commercial and military vessels for Maritex bearings.There are a number of advantages not least of which is that no tools are required for install or changing. Epoxy in a thin layer doesn't actually bond but supports the bearing against what can be a rough uneven surface, it also prevents salt water pockets giving rise to corrosion (particularly bad on Al carriers). Using a low melting point type such as 2011 means it softens with heat for removal.
Press fit risks squeezing the bearing to the point that bore closure means the clearances are too small, with a clearance fit you know the ID will be unchanged after fitting. I've never heard of anyone using silicone but it doesn't surprise me, The problem is the side loads on a bearing in a soft material will cause it to move, seeing as the bearings are there to hold the shaft in a straight line this can't help much.

I wonder how many boats, owned by contributors to this site have Maritex bearings - most will be nitrile rubber in a bronze tube though some may have a phenolic case.
I'd certainly agree heating a metal stern tube is perfectly acceptable, but one that is mounted in a GRP deadwood???

 

[Neil_Y]

I wonder how many boats, owned by contributors to this site have Maritex bearings - most will be nitrile rubber in a bronze tube though some may have a phenolic case.
I'd certainly agree heating a metal stern tube is perfectly acceptable, but one that is mounted in a GRP deadwood???

With the question being about removal/fitting the technique pioneered by Maritex can be used on other materials, although you would have to check clearances.

I just hate to read all the stories of people struggling press fitting and using fiddly extractors when there is a more elegant solution.

When we fit bearings in grp and deadwood, the epoxy can easily be split using a sharp chisel. Some installers put release agent on the bearing but as the epoxy layer is very thin it doesn't bond, it just supports. A piece of coarse sand paper on a rod attached to a hand drill cleans up the old epoxy nicely.

 

[alahol2]

I wonder how many boats, owned by contributors to this site have Maritex bearings - most will be nitrile rubber in a bronze tube though some may have a phenolic case.
I'd certainly agree heating a metal stern tube is perfectly acceptable, but one that is mounted in a GRP deadwood???

I've got one of H4's maritex bearings bedded on epoxy. Mainly because the original bearing was white metal and maritex was the only type I could get with a thin enough wall to fit the same carrier. Mine is in a carrier bolted to the GRP 'deadwood'. I've not yet tried to remove it but I've left a few mm sticking out to grasp and a small quantity of heat should release it. Only one season but so far so good.

 

[carpediem32]

Cutless bearing replacement (Cobra 750)

Same arrangement on my old Southerly 95 and quite an easy job to remove the tube and cutless bearing. Much easier to push the bearing out of the tube in the garage at home. It was quicker to remove and replace using 2 people as the nuts inside the hull weren't captive.

Removing the prop. proved to be easy using a puller, some heat and a light side tap with a hammer.

Thanks all for your advice. I have been told I would have to unbolt the engine and move it forward to remove the prop shaft out that way which seems a crazy design. The boat is a Cobra 750 with a substantial skeg, which I don't think would move, to slide the shaft out backwards. I wouldn't want to risk damaging the skeg and had hoped I could maybe cut a slot in the end of the bearing and tap it loose so it would come off over the prop. That said, I guess that would spoil the press fit of the replacement.

Sounds like this could be an expensive, or at least time consuming, job for when it next comes out of the water.

 

[Talulah]

..I have been told I would have to unbolt the engine and move it forward to remove the prop shaft out that way ...

Not so much move engine forward but up so prop shaft can be pulled forward under the engine.
Disconnect the prop shaft. Undo the engine mount nuts.
If the engine is accesible from above (i.e. Cockpit floor access)
Wooden beam across the cockpit seats.
Make up pulley system between beam and engine using ropes and pulleys allready on board.
Raise engine.
Slide propshaft forward underneath.
Usually no nead to disconnect anything else on the engine but check for available movement in seawater cooling pipes, throttle/clutch cables, battery cables etc and disconnect where appropriate.
Once you've done it once you realise it's a doddle.
I should add that a lot of boat yards have a tool made up for extracting the cutlass bearing without removing propshaft.
It usually slides over the propshaft and has teeth cut into it to grip the cutlass bearing so it can then be pulled out.
More difficult cases require the prop shaft removed and the cutlass bearing cut out in pieces.
A flap wheel sander is then used in the electric drill to clean up the inside of the carrier.

 

[carpediem32]

That sounds a good plan although I have no overhead access so would have to jack the back of the engine up (carefully) about 6" to slide the shaft out under the gearbox. Better still if I can find a yard with a special tool available. I might then leave it up to the experts....