kashurst
Well-known member
The shaft looks pretty good. If it turns enough to do the coupling great. Get it all going and see how it feels after some use.
Failed to remove the shaft coupling
- Thread starter Lucas Gan
- Start date
Lucas Gan
Active member
Thanks.
Regarding the coupling cutting. Here is my experience. The last time I cut the key position, I nearly damage the keyway on the shaft. Just less than 1mm to touch the shaft keyway (I am grinder beginner!). Luckily only damaged the key, not the keyway. So this time I will not cut from the keyway position, I will cut two sides not on the keyway because making two cutting scratches on the shaft surface doesn't affect anything. But if the keyway is damaged will be a disaster as that is where the power is being transferred from the gearbox to the shaft.
Regarding the coupling cutting. Here is my experience. The last time I cut the key position, I nearly damage the keyway on the shaft. Just less than 1mm to touch the shaft keyway (I am grinder beginner!). Luckily only damaged the key, not the keyway. So this time I will not cut from the keyway position, I will cut two sides not on the keyway because making two cutting scratches on the shaft surface doesn't affect anything. But if the keyway is damaged will be a disaster as that is where the power is being transferred from the gearbox to the shaft.
Last edited:
fisherman
Well-known member
ermm.....scuse me.....If the shaft is tight in the cutless, why change it? Have I missed something?
Lucas Gan
Active member
Now I am not going to change it. Just want to withdraw the shaft but found it was too difficult yesterday. Then thought this bearing may be worn out need replacing. But today become easier to turn the shaft for no reason. I think it should be ok to withdraw the shaft, just take longer than the other shaft.
AndieMac
Well-known member
Cutless bearings usually wear and allow lateral shaft movement, but they can also delaminate internally and cause binding on the shaft, which could be part of Lucas’s problem.
Often it’s only one side (either port or stb) binding, but can create a slight overheat in the engine temps at cruise revs and clunking into gear.
Tight shafts can be withdrawn with the help of a webbing strap wound around the shaft at the stern tube as a forward connection point and a small come-along winch using the aft end of the P bracket as an aft anchoring point.
As the shaft slowly withdraws during the winching, squirt dishwashing detergent at the forward end of the P bracket to lube the shaft as it travels through the tight cutless bearing. Keep resetting the webbing strap, winching and lubing until the shaft is out.
Often it’s only one side (either port or stb) binding, but can create a slight overheat in the engine temps at cruise revs and clunking into gear.
Tight shafts can be withdrawn with the help of a webbing strap wound around the shaft at the stern tube as a forward connection point and a small come-along winch using the aft end of the P bracket as an aft anchoring point.
As the shaft slowly withdraws during the winching, squirt dishwashing detergent at the forward end of the P bracket to lube the shaft as it travels through the tight cutless bearing. Keep resetting the webbing strap, winching and lubing until the shaft is out.
Last edited:
Lucas Gan
Active member
cherod
Well-known member
i would be wary of using mild steel , it is going to rust like crazy and may require another epic if ever you should have to remove it ,,, my , recently fitted , keys were made of phospher bronze ( or whatever ) , same as the new props were made from .
Lucas Gan
Active member
So, is it brass key better than mild steel? I can buy a brass key if this is true. What do you guys suggest? Brass or mild steel?
I was trying to find a stainless key, but can't find it anywhere.
Thanks.
I was trying to find a stainless key, but can't find it anywhere.
Thanks.
Bran
Active member
If you have purchased the key steel you linked to earlier then stick to that, it’s not mild steel, it’s key steel, should be ideal for your application. Key steel is normally en8 so it has a higher tensile strength than normal mild steel, maybe prone to more corrosion but should be away from that near your gearbox.
Last edited:
Lucas Gan
Active member
Oh. Good to learn that. Yes, I bought it from there said it's key steel.
Lucas Gan
Active member
My p bracket cutlass bearing is still too tight. I used a pipe wrench to turn it by the middle of the shaft, made so many scratches on it. It only moved around 60cm after around 2 hours of trying. Still have 2 meters to go!
Last edited:
kashurst
Well-known member
I think you will have to try and bring the cutlass bearing out with the shaft as per post 193. The scratches on the prop shaft will smooth out with a file and emerge cloth.
Lucas Gan
Active member
That is something I am trying to avoid. I am afraid the p bracket bearing is not easy to remove while I don't have the right tool at the moment. I could try to make another DIY puller in a few days. But worries like the shaft coupling still can't remove even with my DIY puller. That will cause more time and headaches.
The boatyard people tell me to use fire to destroy the bearing rubber to move the shaft out then use a saw to cut the bearing brass tube.
Struggling!
The boatyard people tell me to use fire to destroy the bearing rubber to move the shaft out then use a saw to cut the bearing brass tube.
Struggling!
Last edited:
fisherman
Well-known member
Is the internal stuffing box slacked off? Take it off if you can, allow the shaft to wobble.
Lucas Gan
Active member
The stuffing box already removed. Nothing else holding the shaft but this p bracket bearing only now.
The shaft can wobble inside the stern tube already.
The shaft can wobble inside the stern tube already.
cherod
Well-known member
looks like you are having about as good a week as i am 
Lucas Gan
Active member
Read something said it could be a wrong size of bearing if it's too tight. This might possibly right as one of the previous owner might accidentally replaced a 45mm bearing for this 1-3/4 inches shaft (44.45mm). I also almost buy a 45mm coupling and seal for it. Luckily have Croftie remind me that could be 1-3/4 inches which is correct.
vas
Well-known member
was thinking about it btw, imho it's important to remove and replace with the right one, else you're stressing the engine and overheating the shaft (possibly...)
Anyway, if it's 1 3/4, the 45mm would be a v.loose fit not a tight one!
more confused!
Anyway, if it's 1 3/4, the 45mm would be a v.loose fit not a tight one!
more confused!
Lucas Gan
Active member
Oh yes. You are right! Shouldn't be a 45mm bearing!
Now I have three options:
1. Continue to spend two days to remove the shaft in this extremely tight bearing, then polish the bearing rubber inside to loosen it, then make the job done by next Monday (relaunch date booked) and back to the water.
2. Just replace the new coupling and seal, don't withdraw the whole shaft, just let it be that tight. This can be done today, and the boat back to water next Monday.
3. Expand hardstanding for one or two weeks, replace both the bearings on two shafts.
What is your choice?
Now I have three options:
1. Continue to spend two days to remove the shaft in this extremely tight bearing, then polish the bearing rubber inside to loosen it, then make the job done by next Monday (relaunch date booked) and back to the water.
2. Just replace the new coupling and seal, don't withdraw the whole shaft, just let it be that tight. This can be done today, and the boat back to water next Monday.
3. Expand hardstanding for one or two weeks, replace both the bearings on two shafts.
What is your choice?
kashurst
Well-known member
I would go with option 3. Probably not what you want to hear but there is something wrong with that cutlass bearing and you don't want it to cause other damage to gearbox etc. Especially now you know about it.
