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-   -   Prop shaft / cutlass bearing overhaul (http://www.sailnet.com/forums/gear-maintenance/99651-prop-shaft-cutlass-bearing-overhaul.html)

SchockT 05-20-2013 04:04 AM

Prop shaft / cutlass bearing overhaul
 
Well, I just hauled my boat this weekend, for the first time in almost 3 years! First let me say that I am VERY impressed with Petit Horizons antifouling paint! After all this time the only significant growth I had on my hull was the spots where the paint wore off completely! I could have easily got another season out of that 1 coat of paint!

On the other hand, I inspected my cutlass bearing and decided that it was time to replace it. Of course, as with all jobs on a boat, it snowballs! Given that I have to pull the prop shaft anyway, I should also deal with the stuffing box. I have had the boat for 9 years, and I have never done it. I have no idea when it was last done so it would be prudent to replace the hose as well.

All of this is new to me since my last boat had an outboard. I understand the principles involved, since I am a mechanical kinda guy but I am looking for some guidance on a couple of issues. A quick search online reveals that there is some debate as to which is better for packing, the old school waxed flax, or the "new fangled" teflon. I tend to lean towards modern solutions, but is it true that with teflon packing you don't need to have any water seepage as some sites suggest? Is there a down side to modern packing materials? Also, I have noticed that my prop shaft is not perfectly aligned with the cutlass bearing. It exits the shaft log slightly off center, and is slightly "cocked" in the cutlass bearing. I am assuming that it is simply a case of loosening off the engine mounts and nudging the alignment a bit upon re-assembly. Is there any tricks to achieving the best alignment?

While we are on the subject of prop shafts, I am also curious about zinc placement. I have always placed my zinc several inches away from the cutlass bearing because I didn't want it to interfere with water flow through the bearing. At the same time I don't want to place it too far from the strut because the weight could amplify any slight imperfections in the prop shaft, causing more vibration. Are there any guidlines as to how close you should put a zinc to a cutlass bearing, of am I over-thinking things?

sony2000 05-20-2013 10:03 AM

Re: Prop shaft / cutlass bearing overhaul
 
My knowledge is a bit limited but I'm mechanical. The shaft flag must attach to the engine with an egual space all around before bolting the two together. Moving the engine might change that. My stuffing box is attached to the boat with a flexible poly tube so it should compensate a change.
The shaft must enter the cutlass bering, alligned perfectly to minimize wear.
Its hard for the zinc to impede the water from reaching the bearing.

JimsCAL 05-20-2013 08:59 PM

Re: Prop shaft / cutlass bearing overhaul
 
I've also had good experience with Pettit Horizons. Good stuff and a good price.

Having replaced strut bearings and repacked stuffing boxes a number of times over the last 25 years, here's some thoughts. Pulling the shaft is a pretty big job (especially if you have to drop the rudder), so do everything while its out so you don't have pull it again in a year or two. I've had good luck with the fancy packing, but I don't agree with those that say you don't need a slow drip for lubrication. Yes the teflon may be less likely to overheat, but it still needs a bit of water for cooling and lubrication IMO. Check out Mainesail's excellent tutorials on replacing a strut bearing and repacking a stuffing box.

onestepcsy37 05-21-2013 12:30 AM

Re: Prop shaft / cutlass bearing overhaul
 
a few months ago, while i was hauled out, i decided to replace my cutlass bearing.

it had only the slightest amount of play in it, and i guessed it would be good for maybe two more years, but i didn't want to haul out again in two years so i decided to go ahead with replacing it. i'm fairly handy and do much of my own work, but after looking it over i decided to have the really good mechanic in the yard do it for me.

a couple of weeks and $800 later, it's replaced. in order to get the bearing out he had to remove the shaft; which meant he had to remove the prop as well in order to clear the rudder. when he pulled the shaft it was obvious that it had some serious wear grooves in it, so he replaced that too; and the coupler as well, because the four bolt holes that keep it attached to the v-drive were worn out of round. i asked him to replace the packing gland hose too; it's the cheapest part in the whole system. and four new hose clamps. the packing gland was in excellent shape, so that remains, but he did repack it of course.

i'm back in the water now, and the whole thing looks pretty good and more importantly, i trust it. i'm fastidious about anything below the waterline. anything above the waterline can often be fixed whenever, but below is usually an emergency....

deniseO30 05-21-2013 12:35 AM

Re: Prop shaft / cutlass bearing overhaul
 
for DIYers it's common drop the rudder, pull the shaft..... but for pros... I would think they should have the right tools BUT, Prop pullers and Cutla$$ bearing puller$ aren't cheap!

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Ritchard 05-21-2013 05:04 PM

Re: Prop shaft / cutlass bearing overhaul
 
Quote:

Originally Posted by deniseO30 (Post 1033089)
for DIYers it's common drop the rudder, pull the shaft..... but for pros... I would think they should have the right tools BUT, Prop pullers and Cutla$$ bearing puller$ aren't cheap!

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I made one.

http://www.sailnet.com/forums/showpo...&postcount=283

SchockT 05-22-2013 01:34 AM

Re: Prop shaft / cutlass bearing overhaul
 
Well, I thought it would be no biggie pulling the prop shaft. Being a tiller boat the rudder comes off easily. Unfortunately the prop shaft coupler does not want to part with the shaft! It is very rusty, and likely has not been removed in the life of the boat! I have it disconnected from the transmission but there is no room to get a puller on the end. I have hit it with PB Blaster and it is sitting overnight. I have an idea to make a puller that will fit. Normally when faced with such a problem I would just pull out my acetylene torch and heat it up, but I am very hesitant to do that in such a confined space with the fuel tank, fuel filters and fuel lines all in the immediate vicinity! Worst case scenario something will have to be cut off. The coupler or the shaft, depending on which is cheaper! My other option is to leave the shaft in place and forgo the stuffing box hose replacement, and just invent a tool to remove the cutlass bearing with the shaft in place.

JimsCAL 05-22-2013 08:49 AM

Re: Prop shaft / cutlass bearing overhaul
 
You can make a puller easily from a piece of steel plate. Just drill some holes at the spacing of the coupling bolts. Use a socket from a socket wrench set between the plate and the end of the shaft and then tighten the bolts or threaded rods with nuts, pushing the shaft out of the coupling.

deniseO30 05-22-2013 10:03 PM

Re: Prop shaft / cutlass bearing overhaul
 
The one that can be bought from Inboard marine tooling company, looks like this http://www.henrysmith.com/images/transcouppuller.gif

SchockT 05-23-2013 01:47 AM

Re: Prop shaft / cutlass bearing overhaul
 
Thanks for the suggestions!

I got my hands on a harmonic balancer puller that should do the trick if I can get a shorter pusher screw for it. I only have 2.5" to work with!

http://images.palcdn.com/hlr-system/...61/8261653.jpg

my plan "B" is a short piece of shallow Unistrut with a 3/8 bolt and captive unistrut nut for the pusher.

I didn't have time to work on it today since I had to get the bottom paint on between weather systems!


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