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New cutless bearing installation hiccup

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jansan

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Jan 22, 2008
38
Catalina 28 Clyde Scotland
Wonder if I could get some feed back.I have come to a halt installing a new cutless bearing to a Catalina 28 Mk 1.

The new bearing is 1 1/4 inch O/Dia with a 1 inch I/Dia -------- that is the bronze meatal tube is 1/16 inch thick.

Using best practice I lightly preheated the " P bracket " and cooled the sleeve prior to screw fitting the cutless bearing into the bracket ( threaded rod plus washers, grease between washers etc etc )

Eventually had to give up halfway into the fitting as the threaded rod had stripped it`s thread ------- yes it was that tight !! 12 inch spanner at almost limit of strength

Cut off half the four inch cutless bearing and then started to intall the two inches left over into the other end of the bracket.

Again had to give up after one inch had been inserted, with extreme force having been exerted to have got that far.

Have decided on a " time-out " ---------- it`s time for a rethink.

I`m left with half the bearing in one side, a quarter of the bearing in on the other side, and with a quarter in fresh air so to speak.

There seems to be three options.

1. Use a larger diameter threaded rod, say 3/4 inch with a less coarse thread, and just force the remaing quarter in. I am convinced that as the first half was beiing pressed in there was a distinct " bulging " of the P bracket boss as the cutless bearing tube progressively entered.This has now evened out now that the other half of the bearing has been forced into the other end of the P bracket boss. I am worried that if I continue I might just split the outer boss of the P bracket. Has this happened to anyone else ?

2. Cut off the last remaining inch sticking out and just go with three inches of cutless bearing ( two inches at one end and one inch at the other) rather the four inches as originally planned for.

3. Leave it as is with one inch sticking out. This leaves four inches of bearing material -------- five inches between ends but with one inch " in fresh air "

All responses gratefully listened to ------ sorry for the long winded explanation.
 
Oct 2, 2006
1,517
Jboat J24 commack
A bearing like this cant be installed fast enough to allow heat and cool to work


When i press in or pull in bushings the big issue is how the tools are setup so it gets started straight

I will make tools many times that fit in both the housing and bearing that allow this to happen as once it gets a bit off its easy to dammage it which happend in your case

What size rod did you use and fine or corse thread ?
 
Jun 2, 2004
5,802
Hunter 37-cutter, '79 41 23' 30"N 82 33' 20"W--------Huron, OH
You need to start over. Remove the cobbled bearing. Then rent or borrow a real bearing tool. They are very heavy duty with very fine threads, designed to not booger up the bearing under all that pressure. Make sure you use some emory paper and get the inside of the strut very clean and smooth. It will still go in hard. This assumes that the lock screws are not protruding into the hole. :)
 

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Dec 2, 2003
1,637
Hunter 376 Warsash, England --
I admire your resourcefulness in trying to use the cut off end of the bearing in the opposite end of the P bracket.
These sleeves are not intended to be a heavy interference or a heavy force fit and the current practice of using a sleeve only 1/4" larger in diameter than the shaft leads to very thin walled sleeves. This, in turn means they are almost impossible to extract without removing the prop shaft - which, of course, means all the work inside the boat and then a realignment of the engine when the gearbox flange is bolted up again. Much up and down ladders!
So, frustrated, by this I removed my 'P' bracket and had it bored out to 1 1/2" ID and now use the older style cutless bearing with a 1/8" wall bronze tube. These are a much better engineering proposition and will push fit without swelling up when compressed. They also have a decent thickness of wall for the locking grub screws to be dimple drilled into.
Seems to me the makers took one step forward and many steps backwards.
BTW I keep an old sleeve with 1" wide piece sawn out of it along its length. This slips over the shaft and my extractor pulls it into the 'P' bracket thus removing the old bearing as it goes.
All a ten minute job.

Now, returning to your problem, may I suggest measuring the OD of the bearing with a digital calliper to see if it is (now!) oversize. I just measured an old one of mine in the garage and it was dead size to perhaps 1 thou oversize.
I have never seen anyone need to use heat or cold to get them out or in. Gentle tapping with a hammer and drift or compression with a home made tool is normally sufficient.
I have come across cutless bearings in 1 1/4" diameter tuphnol (SRBP) sleeves which might be easier to fit - or at least to sand off the excess diameter.
As yours does seem to have been a heavy force fit then the P bracket could be undersize. Again it needs measuring and, if undersize, perhaps scraping out in-situ using engineers blue on the cutless to get it right.
Sorry as this has now turned into an engineering exercise - but next time it should be a doddle.
 
Feb 6, 1998
11,096
Canadian Sailcraft 36T Casco Bay, ME
1- Must go in straight

2- Should use heavy enough threaded rod or real bearing press.

3- May need to wax or grease the strut and bearing (I prefer wax). If it's not a bad fit often Ivory soap works but if it's tighter then you may need wax or some grease..

4- Remove all remnants of old bearing and start over and be SURE the inside of the strut has no burrs from removal of the old, one especially near the set screw holes.

5- Heating cooling won't help as the bearing wall is so this that by the time you get set up it is back at near ambient..

Many of these bearings are a press fit. While some are sloppy others are not.

Get it straight, use heavy enough rod and grease or wax the inside of the strut and outside of the bearing and be sure of no burrs...

Mine went in fine, and it was a tight fit..
 
Jan 22, 2008
1,474
Hunter 34 Alameda CA
Really soak the strut with penetrant and let it do its work for a few hours.. You should try to remove the piece you just attempted to put in and use it to push the remaining part back uphill some. Moving back and forth may loosen it up. Last resort is to remove the shaft and use a saw blade to carefully split the bearing lengthwise and remove the pieces. Coat the new one with grease before installing. It will be easier to remove when that one has worn out.
 
May 11, 2005
3,431
Seidelman S37 Slidell, La.
Might I suggest

Get yourself a brake cylinder hone, and lightly hone the inside of the strut. Not so much as to make it any larger, but enough to clear out any burrs or bulges.
 
Nov 1, 2009
10
Catalina 27 Worton
I changed the cutlless bearing on my c27 last spring. I used a Morse blackfish that is is 1x1 1/4 x4. I screwed up the first one, it got tight and the end mushroomed. So I removed that one and sanded with real fine paper and polished the inside of the strud. I lubed the bearing with soap and used a 3/4 inch threaded rod with nuts and large washers to press it in. I had one nut welded to the rod and the other presses the bearing in. I put some electrical tape on the threads to protect the bearing. From the welded nut four inches on the thread. The first time I tried I think I worked to fast there was a lot of heat built up. The second time I pressed it in a little at a time. I would press in a 1/2 inch and wait a few minutes. It went in perfect.
 
Dec 25, 2008
1,506
catalina 310 Elk River
Funny how this should come up. I'm going to be dealing with the same job.
Here are my issues to date:
1) The Johnson Duramax "BACK" 1.25 OD x 1" ID x 4" that has been sent to me is not manufactured to spec.
a) The casting wall thickness according to their spec should be .0469 or 3/64, I'm getting .07. The issue I have with this is, with the rubber so thin that any slight mis-alignment and your going to score the shaft. The tolerances are already tight with a 1.25 OD and a 1" shaft design, but there is no reason to make it worse by a thicker casting wall.
b) The end should be cut off squarely, it's not, this is just sloppy workmanship.

In the context with this thread I would be dam sure the end of the bearing was cutoff square during manufacture because if it isn't, than one would be applying uneven preasure when insearting causing it to bind as you are experiancing.
 

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Jan 2, 2009
35
beneteau 323 Riverside NJ
Hmmm, I have to do thiis same job on a beneteau 323, however I think the job is a bit easier, although I have never tried. I am saving the job for next spring. If anyone has done it on beneteau's, I would be interested in any tips you might have?
 

jansan

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Jan 22, 2008
38
Catalina 28 Clyde Scotland
Thanks to all who have contributed.

Just to clarify ---------- the prop shaft was removed prior to work commencing.

The two halves of the bearing now firmly installed are not deformed even after the stresses applied to the ends . The propshaft is to all intents and purposes a perfect fit and turns without undue friction within the two halves of the new bearing.

Other than the fact one inch is sticking out it would have been a highly staisfactory result.

Presumably if I was to cut these two parts out now the bore of the " P bracket " will have been enlarged/resized so making the refitting of another cutless bearing from the same supplier a much easier fit. I am assuming the bore of the " P bracket " will not be springing back to it`s original size.

But the big question is ----------- is it really necessary to replace it ? It`s in place- ----- other than it`s now in two halves, and there is no obvious damage " size-wise " to the rubber part of the bearing or the brass/bronze outer tube. If the outer tube has bellied it isn`t immediately apparent, and if it had, I would have expected the internal dimensions to have also changed

A point of note in the passing.

When offering up the propshaft ( with flange attached ) to the output flange of the gearbox it is noticeable that the two are not in an exact line-up. It is probably to be expected that now that the boat is on the hard that there will be a discrepancy anyway between " in the water and out of the water" alignment whether I replaced the cutless bearing or not. But I get the impression that now that there is absolutely no play between the cutless bearing and the propshaft that maybe now the two mating flanges could be in a slightly different relationship than before.

To " Witzend " ------- the ends of my bearing were square and true. I reduced the O/Dia with emery cloth prior to offering it into the " P Bracket " to ensure that it was true as it was being forced in. Ialso used lubricant on the tube and in the bracket bore as it became obvious it was going to be a very tight fit. Once I had to cut the tube in half ( half in ---- half out ) I then really worked on the half I cut off with emery paper before trying to fit in the other end of the bracket.

My verdict ( based on a machine tool/automotive engineering background ) is that the tube and the bracket bore are what we used to call an extreme interference fit. In a workshop environment they would be assembled by a flypress. But the tube would have a much thicker wall thickness than the " P bracket " wall thickness, and it would be expected to have material shaved off the tube as it was being forced in.
 
Sep 29, 2008
1,765
Catalina 310 #185 Quantico
Do it right

Ed (do it over), Main Sail (keep it straight) and Nice n' Easy (brake cylinder hone) gave some really great advice. The boat is out of the water and it will never be easier to do than now. I do suspect there is a burr somewhere (again the brake cylinder hone is a great idea) and it is better to get this right.
 
Dec 2, 2003
1,637
Hunter 376 Warsash, England --
Jansan,
I found my 1" od propshaft would sag by almost 1/2" when supported only by the cutless. I have a Dripless stern gland which does not support the shaft - and anyway this had been removed whilst I was replacing the 'P' bracket and getting everything in line.
The sag was due to flexing of the shaft so I would not expect it to be perfectly aligned when offering up the flanges.
I suggest putting in the bolts loosely to centralize the flanges and then setting the alignment to 4 thou.
 
Dec 25, 2008
1,506
catalina 310 Elk River
Jansen, what is the condition of the shaft that would be now inside the bearing that use to be out. If it is rough it will just tear it up.
 

jansan

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Jan 22, 2008
38
Catalina 28 Clyde Scotland
The shaft surface condition in the area of the bearing is OK`ish, certainly I have no worries in that regard. Prior to finishing the job I`m quite certain it will polish up really well.
There were some witness marks on the shaft surface which the old rubber insert had left --------- the rubber had detached from the bearing tube and was then solid on the propshaft whilst turning inside it. How long this had happening I dont know. From the witness marks maybe several years !
 
Dec 25, 2008
1,506
catalina 310 Elk River
Then...fundamentally I don't see any reason leaving it stick out would cause any problem. The side forces on a 1" extension are nil, especially on the non-prop side.
So, you're indicating that the rubber brass interface failed and the rubber fused to the shaft? What is you shaft made of, SS or brass? Either one, seems amazing this would happen. Maybe it was run in gear out of the water for a period, maybe to suck in polypropylene glycol for winterization and the shaft got too hot and melted the rubber and stuck to the shaft???
Why the hell the strut is not designed as two halves bolted together encapsulating the bearing I will never understand.
Take pictures please.
 
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jansan

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Jan 22, 2008
38
Catalina 28 Clyde Scotland
Then...fundamentally I don't see any reason leaving it stick out would cause any problem. The side forces on a 1" extension are nil, especially on the non-prop side.
So, you're indicating that the rubber brass interface failed and the rubber fused to the shaft? What is you shaft made of, SS or brass? Either one, seems amazing this would happen. Maybe it was run in gear out of the water for a period, maybe to suck in polypropylene glycol for winterization and the shaft got too hot and melted the rubber and stuck to the shaft???
Why the hell the strut is not designed as two halves bolted together encapsulating the bearing I will never understand.
Take pictures please.
The propshaft is either made of brass or bronze. Here`s a couple of photos showing the witness marks left by the rubber bearing which had fused itself to the shaft ---- you can just make out the lines of the flutes.

When I next get up to the boat I`ll take some pictures of the P bracket and the new bearing. I got my bearing from www.tidesmarine.com ( the UK version ) ------ the outer shell material is corrosion resistant brass but just what the exact 1 1/4 inch O/Dia size was I can`t say.

With hindsight I wished I had been able to establish the interference fit dimensions between the tube O/D and the bracket`s I/ D to be able then to have given you some guidance.

We`re all Einsteins after the event.

If all else fails after you have started the job and it is proving to be a problem ------ dramatically reduce the tube O/D with emery paper, cut off what you can`t get in before it bellows, and what you cut off try that into the other end of the bracket.
 

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Dec 25, 2008
1,506
catalina 310 Elk River
Is your shaft pitted? It looks like some deprivation has taken place. Make sure it is smooth so you don't eat up the new bearing. Who was the manufacture of your bearing? I could not find them at your posted link.
As I indicated before, the Johnson Duramax "BACK" 1.25 OD x 1" ID x 4" that has been sent to me is not manufactured to spec. I have sent it back to them. We will see if they come clean with the issues. I suspect there has been a change to make the casting thicker so it won't mushroom when inserting, although when I complained that the ends were not cut off square and that could cause uneven pressure when inserting under load leading to binding, their response was "they should just slip in, no unnecessary force required" so if they come back with "we are using a thicker shell to prevent mushrooming" they will have contradicted them selves. There literally is very little rubber in the new “Back” bearing and this is very concerning to me because if things get a little out of kilter scoring the shaft is more likely.
 
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jansan

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Jan 22, 2008
38
Catalina 28 Clyde Scotland
Is your shaft pitted? It looks like some deprivation has taken place. Make sure it is smooth so you don't eat up the new bearing. Who was the manufacture of your bearing? I could not find them at your posted link.
As I indicated before, the Johnson Duramax "BACK" 1.25 OD x 1" ID x 4" that has been sent to me is not manufactured to spec. I have sent it back to them. We will see if they come clean with the issues. I suspect there has been a change to make the casting thicker so it won't mushroom when inserting, although when I complained that the ends were not cut off square and that could cause uneven pressure when inserting under load leading to binding, their response was "they should just slip in, no unnecessary force required" so if they come back with "we are using a thicker shell to prevent mushrooming" they will have contradicted them selves. There literally is very little rubber in the new “Back” bearing and this is very concerning to me because if things get a little out of kilter scoring the shaft is more likely.
You`re quite right there is a degree of pitting there. Assuming the bearing is " frictionless " ie it runs on water I`m hoping it will be OK. Prior to final installation I shall give it a proper polish up

best of luck with your installation (ps. if you search www.tidesmarine.co.uk you`ll find it under their listed parts ( GBP price list ) ) I`m assuming the US company will be able to source it if you give them a call
 
Dec 25, 2008
1,506
catalina 310 Elk River
Here is the problem:
I just spoke to Duramax about the bearing they sent me that was out of spec. To put a long story short, they admitted that the catalog dim. for the wall thickness for the "Back" (1.25 OD for a 1" shaft) is incorrectly stating as 3/64 (.046) and should be .058 mine measured close to .70 so there was very little rubber inside the shell (see photo).

Morris manufactures the "Blackfish" same Dim. except the wall is listed as 1/32 or .031. which seem a little thin and may be prone to mushrooming in a tight fit situation. I'm trying to find someone who can spec the part out to see what it really is.

Here is the rub:
Do I go with the Duramax and not have to worry as much about mushrooming during installation, but do worry about scoring the shaft if things get out of alignment, or do I go with the thinner wall Morris and hope it slides in with out too much force and then have much thicker rubber wall to buffer against scoring?
 

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