Cutless bearing replacement

[roaringgirl]

We're hauling out tomorrow, and I will be replacing the cutless bearing. I haven't done this job before and having read the instructions online about how to do it, I'm left with a couple of questions:

1. What do the 2 blue dots on the new one signify?

2. My bearing is in the stern tube - we don't have a P-bracket, so I can't reconstruct a hacksaw around it to cut up the old one. I have made a press with dowel and washers and I was wondering if it makes sense to press the old one out with the new one? Any comments?

Thanks!

 

[Tranona]

Can you remove the bearing housing from the stern tube? You should find 2 grub screws, one either side of the housing. Often difficult to see under years of paint. Remove as the bearing won't come out. Would not use the new one, but depending on size you could use a large socket. Don't know what the blue dots might mean - not seen those before.

 

[roaringgirl]

Yes, there are grub screws. I had assumed they were holding the bearing, but perhaps you're right - I hadn't considered the possibility of removing the housing. I will have to see, once we're in the cradle.

 

[Tranona]

If the housing is removable then it is a straightforward job. If it is not then you will have to cut the old bearing out. Typical removable housings are screwed onto the stern tube and locked in place with either screws or bolts into the deadwood. Probably need a big pair of stilsons to shift as the housing will be bedded on sealant.

 

[roaringgirl]

Hmm, I haven't taken off the PSS seal yet, so I don't know what I'm going to find on the inboard end. The outboard end of the housing is flush with the end of the fibreglass of the prop tube, so no chance to grip it there...

 

[Ardenfour]

I cut mine out using just a hacksaw blade. The brass tube is quite soft, so easier than it sounds.

 

[BobnLesley]

I cut mine out using just a hacksaw blade. The brass tube is quite soft, so easier than it sounds.

This, or easier still if you can borrow a reciprocating saw. Before removing the housing give some thought to refitting it, some can be absolute pigs to resecure.

 

[Stemar]

On my Snapdragon, the cutless bearing was in a mounting on the end of the stern tube, attached by two bolts into the GRP. If yours is the same, take those off, then the mounting unscrews from the tube, but mine was a left hand thread, which caused some difficulty before I twigged.

 

[roaringgirl]

I've made up a rig for pressing out the old one in-situ, hopefully this will work and I won't need to remove the liner.

 

[LadyInBed]

If the tube housing is bolted in, be aware that when you unscrew the bolts, the nuts on the inside of the hull might not be captive!
If you can't get to the internal nuts, don't apply any forward pressure to the bolt shaft which could cause the nut to 'unbed'.

 

[BabaYaga]

Hmm, I haven't taken off the PSS seal yet, so I don't know what I'm going to find on the inboard end. The outboard end of the housing is flush with the end of the fibreglass of the prop tube, so no chance to grip it there...

Are you sure it is an actual housing that you see? Or might it be just the brass shell of the bearing?

 

[BabaYaga]

I cut mine out using just a hacksaw blade. The brass tube is quite soft, so easier than it sounds.

I found this type of saw quite useful for this task:
Gun Saw Set 24TPI Metal/10TPI Wood/Plastic

 

[NickRobinson]

Small word of warning, disturbing the screwed on housing on an elderly deadwood may cause problems
I've changed non-p bracket cutless bearings by the hacksaw and narrow chisel (to collapse inwards) method mentioned.

 

[Laysula]

Small word of warning, disturbing the screwed on housing on an elderly deadwood may cause problems
I've changed non-p bracket cutless bearings by the hacksaw and narrow chisel (to collapse inwards) method mentioned.

Yup. I did one on a Cobra 850 years ago. When I unscrewed the housing the stern tube just crumbled. I had to chop the rest of it out and replace the whole lot. Pig of a job.

 

[roaringgirl]

PSS seal removed, propshaft clamp bolts removed, clamp grub screw removed, propshaft won't budge. Any ideas? I'm thinking maybe something similar to a ball-joint separator might work (there's only about 3cm of exposed shaft between the end of the stern tube and the prop)

 

[NickRobinson]

Shaft stuck to prop? (Three leg puller, heat and taps)
Shaft stuck in coupling? There is a trick, unbolt flange to gearbox, insert packing on the exposed end of the shaft and replace flange bolts to wind out the shaft. Not advised to welly the gear box flange...

 

[LadyInBed]

There is a trick, unbolt flange to gearbox, insert packing on the exposed end of the shaft and replace flange bolts to wind out the shaft.

Another ploy to use in conjunction is to remove flange to shaft bolts, insert metal plates into the gaps then put the bolts back in from the reverse end and tighten against the plates. This will help break any rust seal around the shaft.

 

[roaringgirl]

Update: propshaft out, slots cut in old bearing, but the bastard won't move. I wrecked the threads on some M19 nuts trying to press it out. The ham-fisted goon that put it in used some kind of sealant. There's no liner in the tube, just glass.

 

[BabaYaga]

Update: propshaft out, slots cut in old bearing, but the bastard won't move. I wrecked the threads on some M19 nuts trying to press it out. The ham-fisted goon that put it in used some kind of sealant. There's no liner in the tube, just glass.

The first time I replaced a cutless bearing, the original was also glued into the GRP stern tube, although that bearing had a phenolic shell, not brass.
It's a long time ago, but I seem to remember that the trick was to make two parallel cuts fairly close together, maybe 10mm, and start by prying that section out.
Once that was out it was not difficult to break out the rest of the shell, using a narrow wooden wedge and a hammer to break the bond.