Replacing the Cutlass Bearing

Talulah

Talulah

Well-Known Member
Joined
27 Feb 2004
Messages
5,824
Location
West London/Gosport
Visit site
The boat is out and I'm in the throes of replacing the cutlass bearing.
The cutlass bearing housing is mounted to the hull hence the bearing is only accessible from one end.
I’ve removed the prop shaft and started to make longitudinal cuts in the bearing so I can collapse it in on itself to get it out. After a couple of hours with a hand padsaw I’ve made very little progress and have retired back home to come back tomorrow with a bigger hammer! The bearing feels well and truly bonded to the housing.

Tomorrow I shall also be armed with the electric jigsaw but the blades will only reach about 110mm into the inside of the bearing. (The bearing is about 145mm long.) Maybe I’ll be able to extend the cuts with the padsaw. (I don’t have an electric reciprocating saw.)

But why do they make these bearings like this? In order to make removal easier why not have longitudinal cuts in the bearing already? If you had four cuts that extended for three quarters the length of the bearing then inserted the bearing with the cut end first removal would be so much easier. You would just have to finish the cuts. Can anyone think why I should not do this to my replacement bearing?
 
They don't all work like that.
We supply cutless bearings that we advise are fitted as a clearance fit bedded on epoxy, to remove in a stern tube either heat stern tube or get a sharp chisel and break the epoxy bond, the bearing slides out.

Fitting as a clearance fit allows you to confirm carrier alignment, the bearing should spin on the shaft and in the carrier, press fitting was used before good epoxies were developed.
 
bearing

some bearings (like mine) have a small grub screw half way along the length of the housing. Mine was a PITA to get out, and I had to remove the housing from the boat. Mine had two bolts on each side, which had to be removed first, before unscrewing the housing from the stern tube. you need to make sure the stern tube does not rotate (like mine did) otherwise you need to seal that in too. Once it is out it is obviously quite easy to tap the old bearing out, after removing the grub screw!!!
 
Presumably the housing cannot be removed. You're in for a very tedious task. A much more effective way of cutless removal, with no risk of damage to the housing, is with a slide hammer. The bad news is that you'll need to know someone with the equipment, a lathe etc, to make one up to suit your shaft diameter. Just a suggestion !
 
Make yourself a puller. At one end a series of thick washers whose od is the id of the bearing carrier. At the other end a piece of tube of the same id as the carrier (an old bearing is good for this. ) Between the two a piece of threaded studding and nuts.

You've given yourself a real job trying to saw a cut in the bearing and you shouldnt use impacts from hammers.
 
heres the puller idea in pictorial form.

http://www.diybob.com/diyCutlessBearing.htm

May also be done without removing the prop shaft.
1. undo any retaining screws on the stern tube.
2. remove prop.
3. get some PVC tubing (or an old cutlass bearing as suggested previously)that will just fit into the stern tube.
4. use the tubing to tap the bearing out of the stern tube & towards the engine. or If this isn't possible, cut a slot along the tube's lenght so you can fit it around the prop shaft, and tap bearing towards the outside world.

rgds
 
As Higgs sais pullers rather than hammers. It's simple but needs someone inside to line up the discs on the bearing. It is a pig of a job when its been press fitted.
 
The problem is you can't get to the far side. The tool in the digram is fine when the bearing is mounted within a pbracket/strut.
In our case the housing is mounted against the hull and the prop shaft tube is then a couple of feet long. You would need a long tube of the correct size to push through from the inside of the boat along the prop shaft and then I suspect you would hit the end of housing, not the bearing itself. Hence the reason for cutting it and collapsing it in on itself. It may be a slide hammer will work once most of the bearing is collapsed.
I'll post back tomorrow evening with how far I got!
 
You seem to have a set-up rather similar to mine. My prop shaft is obscured for a distance of around 3 ft. Don't worry about the possibility of damage with a slide hammer. The important thing is to get solid, metal to metal impact, with absolutely no cushioning effect that plastics etc would cause. Quite moderate tapping should then suffice to persuade the bearing out. I wouldn't bother with further sawing. (But do make sure any grub-screws etc are removed.)
PS. The other important point is to avoid getting any part of your anatomy trapped by the slide!!
 
I removed the cutless bearing from my Vancouver 27 in just over 1 hour with the prop shaft left in place using a tubular cutter I made up from a 35mm dia holesaw (available from any hardware shop) welded to a length of steel tubing of slightly smaller diameter and about 14 inches long. With the prop removed the whole cutter assembly was slipped over the prop shaft from the outside (leaving rudder and skeg in place) and rotated to cut through the bearing in no time. The job could be done single handed using some sort of power drive on the cutter tube - but I enlisted the help of a couple of crew and we rigged up a simple manual power source by taking a couple of turns around the cutter shaft with a rope and heaving to and fro. Piece of cake! Use a wooden block on the back of the cutter shaft to push the cutter forward - Note - the end of the tube gets HOT! You just need to keep the cutter head clear of swarf by withdrawing it regularly. The holesaw needs to be a couple of mm smaller in diameter than the bearing to ensure you don't cut into the housing. Can supply photo if required.
 
Bosun Higgs said:
Make yourself a puller. At one end a series of thick washers whose od is the id of the bearing carrier. At the other end a piece of tube of the same id as the carrier (an old bearing is good for this. ) Between the two a piece of threaded studding and nuts.

You've given yourself a real job trying to saw a cut in the bearing and you shouldnt use impacts from hammers.
Click to expand...

Unfortunately his is at the end of the stern-tube, so no puller will work.

I had the same problem - use a phenol backed cutless bearing, bed in silicon and leave enough projecting from the end of the stern-tube to get a stillson on and turn the bearing.

Meanwhile get cutting (sorry about the lacerated knuckles)
 
sounds like you need a puller with an internal griping arrangement. there are standard bearing pullers (used by fitters & mechanics) that have reversable clawls (typically 3). You can configure for external or internal gripping on the bearing. Getting a set with the correct reach to grip the back of you bearing would be the challenge.

Worth a google though. I would consider getting a set made up. Sounds like a tool you need for your boat.

something like this (but to suit your situtation!).

http://www.justoffbase.co.uk/Micro-...20eb22a.e3eTaxiMa38Te38Qci0?sc=9&category=109
 
Talulah

It will cost you a fiver at B+Q tp buy a metre of 12mm threaded studding, some nuts and copious washers.
You will also need a 1/2 inch socket set from which to 'borrow' the largest socket that will slide down the stern tube and make firm contact with the inside face of the old cutlass bearing..
The trick is to load one end of the studding with A) that biggest acceptable socket, B) about 3 washers and lastly C) two nuts wound up tightly against each other so that they will remain locked together when you wind the other end of the studding..
With that lot fed down the stern tube from inside the boat,( you may have to shorten the one metre of studding by the way if you have to manouevre it past the gearbox but it will go), you should then have the socket resting snugly against the inner face of the cutlass bearing, and about 200mm (say) of studding exposed and poking out of the rear of the stern tube. This is the basis of your custom cutlass puller...
Now drill a 12mm hole in the middle of a 200mm length of say 50x50mm wood and feed that over the protruding studding, add a washer and a nut and -this is the important bit-add a couple of small offcuts of 50x50 wood between the 200 length and the back of the propshaft to ensure a gap into which the cutlass can slide out as you gently and precisely and without recourse to hammers and implements of brute force and destruction, force the old cutlass out by simply winding down on the back nut.
After 2 inches of cutlass has 'appeared' you have used up the available gap, back off the back nut, add more offcuts and wind up some more etc and Bob's your inexpensive Uncle Cutlass remover..
Takes less time to do than to read through my post !
 
second that Blueboatman
this is the most direct route to get over the hump today.
Just couldn't muster the energy to put the words around it.
Well done. :)
 
Yup thirded, just did mine the same way and have long stern tube and tiny prop aperture. Once I had the bits, took about five mins. Wish I took some photos and would have been easier to explain. Good luck!
 
You must log in or register to reply here.

Share this page

Top