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The problem with trying to get silicone grease into the hole under the allen nut is that you can only get a tiny bit in. So, the first thing I'd do is undo the 3 bolts that hold the front bronze housing onto the gland. Carefully pull the front bronze housing forward and slide it up the shaft making sure you don't damage the gasket between the two as you separate the bronze housing from the gland. Then smear a load of silicone grease into the gland and replace the front housing. Water will come in as you're doing it and this may help flush out any dirt, but it's not going sink the boat unless you take too long!

 

If that doesn't cure it perhaps the prop shaft is slightly worn because of an old or dirty seal so the gland leaks and a new seal and silicone grease alone might not cure the problem. One trick you can do is loosen the shaft in the coupling on the gearbox and slide the shaft about 5mm backwards or forwards and then retighten the coupling. This will seat the seal on a new area of the shaft. Ideally you'd want new seals as well otherwise the old seal might wear the shaft again.

Edited by blackrose
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As far as propshaft alignment goes, because it's a flexible gland alignment is not critical. If you can turn the shaft easily by hand that's good, and another check is to stand above on deck and put the engine into gear at idling using one eye to see if the spinning shaft wobbles. Imagine there was a needle gauge touching the shaft - would there be more than a couple of mm movement? Look at it spinning from a couple of different angles. If there's no wobble then alignment should be good enough.

Edited by blackrose
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How much does the unit leak without the seals.

 

Is it a 'have a good pump in place and do it quickly' job, or is there scope to remove the seal unit, take it to a local seals place, replace the seals, and then return the seal unit back again in the afternoon?

 

 

Daniel

The first time I did the job the answer would be no.

After a tip on forum go tie thick rag round shaft via weedhatch and push up to hull the answer would be yes. It just dripped in. Best way all round is to have spare seals ready.

The problem with trying to get silicone grease into the hole under the allen nut is that you can only get a tiny bit in. So, the first thing I'd do is undo the 3 bolts that hold the front bronze housing onto the gland. Carefully pull the front bronze housing forward and slide it up the shaft making sure you don't damage the gasket between the two as you separate the bronze housing from the gland. Then smear a load of silicone grease into the gland and replace the front housing. Water will come in as you're doing it and this may help flush out any dirt, but it's not going sink the boat unless you take too long!

If that doesn't cure it perhaps the prop shaft is slightly worn because of an old or dirty seal so the gland leaks and a new seal and silicone grease alone might not cure the problem. One trick you can do is loosen the shaft in the coupling on the gearbox and slide the shaft about 5mm backwards or forwards and then retighten the coupling. This will seat the seal on a new area of the shaft. Ideally you'd want new seals as well otherwise the old seal might wear the shaft again.

Best way to get grease in is with small syringe like the things vet gives you to give pet medicine. Turn shaft as you inject grease and you get more than enough into the gap between seals.

Shaft back in different position is excellent suggestion and it works.

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Be careful moving the shaft too far forwards. Too close to the sterntube collar and the propeller boss will rub on it when in forward gear and wear them both, due to the flexible engine mounts.

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The first time I did the job the answer would be no.

After a tip on forum go tie thick rag round shaft via weedhatch and push up to hull the answer would be yes. It just dripped in. Best way all round is to have spare seals ready.

Ok, so the rag etc is required, unlike a conventional shaft where typically it will seal plausibly even without packing during the re-packing.

 

Obviously having the seals to hand is the way forwards, and has to be a recommended route, but clearly you need to know the size beforehand.

 

Sounds like the process if I where doing it would be;

- Rag round the prop shaft outside the boat.

- Remove seal pack, note seal sizes, take photos etc.

- Refit seal pack with old seals.

- Take numbers/measurements/photos to seal provider and or order over the phone.

- Once you have the seals, return to the job and fit them one sitting.

 

Best way to get grease in is with small syringe like the things vet gives you to give pet medicine. Turn shaft as you inject grease and you get more than enough into the gap between seals.

Shaft back in different position is excellent suggestion and it works.

Slightly surprised there is not method provided, such as a grease nipple or provision of a syringe with the correct thread to match the plug. However it if works it works, and maybe the abily to force high pressure grease in would be more likely to damage/displace the seals than improve things.

 

 

 

Daniel

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After 10 years of boat ownership I only realized last year that you needed to put silicone grease in the unit !!

 

Good to know the rubber seals can be replaced in the water, although mine isn't bad at all.

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Ok, so the rag etc is required, unlike a conventional shaft where typically it will seal plausibly even without packing during the re-packing.

 

Obviously having the seals to hand is the way forwards, and has to be a recommended route, but clearly you need to know the size beforehand.

 

Sounds like the process if I where doing it would be;

- Rag round the prop shaft outside the boat.

- Remove seal pack, note seal sizes, take photos etc.

- Refit seal pack with old seals.

- Take numbers/measurements/photos to seal provider and or order over the phone.

- Once you have the seals, return to the job and fit them one sitting.

 

Slightly surprised there is not method provided, such as a grease nipple or provision of a syringe with the correct thread to match the plug. However it if works it works, and maybe the abily to force high pressure grease in would be more likely to damage/displace the seals than improve things.

 

 

 

Daniel

The size can easily be determined from other members with same size shaft. Mine is 30 47 7. 30 is the shaft diameter. 47 diameter of seal housing. & 7 the seal thickness.

No need nipple or any high pressure the syringe gets plenty in. When renewing seals put grease in before fitting on shaft, fill whole cavity of both seals.

 

post-481-0-30651700-1456837901_thumb.jpg

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The original Vetus seal, at least from 11 years ago, is plain inside. The ones i am using now have a spring wire inside. Hope description means something, see photo.

 

A word of warning. I once changed one on a friends boat aged about 13/14 years. The seals were NOT removable. The whole unit was one lump. The rubber seals were one and the rubber was for lack of correct term glued inside the bronze unit. Vulcanised perhaps is the term.

Anyway this unit is no good for putting loose seals in even if you clear away the rubber its the wrong shape bronze unit internally.

post-481-0-72403700-1456839976_thumb.jpg

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Thanks for the reminder, I had intended to order a spare set of seals when this topic was discussed some time ago with pics and a great description of how to do and a link to a supplier £7 for two delivered (35mm)

They are now ordered

Regards Ray

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Thanks for the reminder, I had intended to order a spare set of seals when this topic was discussed some time ago with pics and a great description of how to do and a link to a supplier £7 for two delivered (35mm)

They are now ordered

Regards Ray

Ray would you post a link as to where you obtained these seals from as I could do with ordering some.

Thanks Fred

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I am just going by what the engineer on Ashby canal told me when he came out and looked at it.

Try putting grease in. What have you got to lose. Could save a lot of cash. You will need grease after a new seal unit is fitted anyway for ongoing maintenance.

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I am just going by what the engineer on Ashby canal told me when he came out and looked at it.

I think you need to investigate the leak further. It must be quite obvious where the leak is coming from as the water tube is a few inches away from the shaft seal. Tie the boat to a tree or bollard, start up and put it in gear and get down there and watch. If it leaks in astern gear all the better because you can tie the bow end only to a tree or bollard, start up, into astern gear and shove the tiller over to the appropriate side, this will swing the stern out so the prop will be away from the bank.

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A bit scary. Of course there is much more pressure with a sea type boat. the prop being deeper in the water I would think. Nothing like that amount of water came in when I changed ours afloat (I did wrap a bin bag around the outside of the tube/shaft thru the weedhatch, but don't think it made a huge difference TBH). Wish I had videod it now, there would have been plenty of time. I would guess at a gallon or so of water came in during the couple of minutes I took to remove the vetus seal, and carefully slide the new Radice seal onto the shaft (didn't ram it on like that guy, he had no choice!). There would have been time to have a brew, and that is the important thing.

There is a small plastic guide for the Radice seal to stop the lips from inverting when inserting (this had happened on my first vetus seal and it never did seal properly from new. I would recommend anybody fitting a new Vetus seal to make a suitable tool out of a plastic drink bottle readily available from any canal/towpath. ) The small bilge pump on our boat easily coped with the water coming aboard.

Time will tell, but to date I am impressed with the Radice (very like the Volvo unit but modified), and for the first time in 12 years have dry bilges when reverse is engaged ;) Of course I can't blame the first Vetus seal for that as it had been installed badly, in fact it was a credit to it that it sealed at all. This was the older type moulded in solid unit, which I prefer TBH.

I keep the old Vetus unit on board for backup purposes only.

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It really depends on how much wear on the rubber tube bearing as to how much water comes in when removing the seal. How old the installation is, how many hours its run, and whether or not the engine and shaft have always been in more or less alignment. Before removing the seal and after disconnecting the shaft from the coupling at the gearbox end it would be worth checking for wear by removing the weedbox lid, grasp the propeller and yank up and down on it, you can gauge the bearing wear roughly by how much free movement,(play) in it, do the same at the inboard end. The ones I've done seals on have all been on fairly new wide beam boats that hardly ever move, but had seriously misaligned engines, from new I expect, which I had to correct. But not much water came in. As others have said, have all the gear ready for the job, new 0 ring for the seal unit too if nec, grease ect. Wrap rag around between prop and tube collar if you wish and have a bilge pump handy.

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Best way to get grease in is with small syringe like the things vet gives you to give pet medicine. Turn shaft as you inject grease and you get more than enough into the gap between seals.

 

Are we using the same type of silicone grease? Mine is too thick to squeeze it out of a syringe - I tried it (and no, there was no needle! tongue.png ). I know there are some thinner types of silicone grease in a tube with a nozzle, but for a water lubricated gland you want the thick stuff.

 

This is the type I use.

 

silicone-grease-60ml-pot-x-50-8-p%5Bekm%

Edited by blackrose
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It really depends on how much wear on the rubber tube bearing as to how much water comes in when removing the seal. How old the installation is, how many hours its run, and whether or not the engine and shaft have always been in more or less alignment. Before removing the seal and after disconnecting the shaft from the coupling at the gearbox end it would be worth checking for wear by removing the weedbox lid, grasp the propeller and yank up and down on it, you can gauge the bearing wear roughly by how much free movement,(play) in it, do the same at the inboard end. The ones I've done seals on have all been on fairly new wide beam boats that hardly ever move, but had seriously misaligned engines, from new I expect, which I had to correct. But not much water came in. As others have said, have all the gear ready for the job, new 0 ring for the seal unit too if nec, grease ect. Wrap rag around between prop and tube collar if you wish and have a bilge pump handy.

Some very good points. There is a bit of up and down wear in our stern gear, getting close to 5000 hrs cruising (not battery charging) on the clock now.

 

Are we using the same type of silicone grease? Mine is too thick to squeeze it out of a syringe - I tried it (and no, there was no needle! tongue.png ). I know there are some thinner types of silicone grease in a tube with a nozzle, but for a water lubricated gland you want the thick stuff.

 

This is the type I use.

 

silicone-grease-60ml-pot-x-50-8-p%5Bekm%

Similar to what I often use from plumbers merchants, though I can get it through the syringes that I use. They are just plastic ones, with a reasonable sized outlet. The Volvo blue grease is very good and much cheaper than vetus own, though dearer than the plumber's pots. Many chandlers seem to stock the Volvo stuff which is handy at times.

There is silicone grease on Ebay that is cheaper but much thinner. I made the mistake of buying some and just used it up on electrical connections, hinges etc.

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Some very good points. There is a bit of up and down wear in our stern gear, getting close to 5000 hrs cruising (not battery charging) on the clock now.

Similar to what I often use from plumbers merchants, though I can get it through the syringes that I use. They are just plastic ones, with a reasonable sized outlet. The Volvo blue grease is very good and much cheaper than vetus own, though dearer than the plumber's pots. Many chandlers seem to stock the Volvo stuff which is handy at times.

There is silicone grease on Ebay that is cheaper but much thinner. I made the mistake of buying some and just used it up on electrical connections, hinges etc.

 

I guess I'll try it through a syringe again and just push harder!

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I guess I'll try it through a syringe again and just push harder!

I use a syringe I got from the chemist, for flushing out ears.(15p)

It's a tight fit in the 'ole and quite strong, so you can give it a good push.

 

Rob.

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