Jump to content

Overtightened packing gland


Featured Posts

Hi  guys,

 

Can't post a picture at the moment, but I have one of those basic packing glands with a bolted in piece that needs tightening up every now and then to push the packing down.

 

The other day I tightened it up and have gone too far as I now have no drip whatsoever, whether in gear or not. I also now have to give the engine a really good rev when it first goes into gear or it stalls, so I'm guessing the prop is so tight it slips on the gears.

 

On the other hand, I can still turn it by hand relatively easily and it doesn't get REALLY hot. I mean it feels probably too hot. I have seen a "warm cup of tea" being an indicator. Well it's more like a fresh cup of tea, I can hold my hand on it for a couple of seconds before it feels too hot to grab.

 

I am pretty sure I will just need to repack it now as it is the same packing that was in there (new) when I bought the boat, about 5 years ago. However, I literally can't afford the few quid I need to get the packing for at least a few weeks.

 

My questions are, is this likely to be bad enough to damage my prop shaft if it remains like so for the next couple of cruises and secondly (and more importantly) is there anything I can do to correct it even temporarily until I can afford some new packing?

 

If I loosen the bolts now, the fitting just slides out there is no "spring" left in the packing. I was wondering if I could loosen it slightly, run it in gear and try to "push" the packing back out? Could this work, or is it likely it has just gone hard and useless now and will stay like it is.

Link to comment
Share on other sites

49 minutes ago, DrunkenDonkey said:

Hi  guys,

 

Can't post a picture at the moment, but I have one of those basic packing glands with a bolted in piece that needs tightening up every now and then to push the packing down.

 

The other day I tightened it up and have gone too far as I now have no drip whatsoever, whether in gear or not. I also now have to give the engine a really good rev when it first goes into gear or it stalls, so I'm guessing the prop is so tight it slips on the gears.

 

On the other hand, I can still turn it by hand relatively easily and it doesn't get REALLY hot. I mean it feels probably too hot. I have seen a "warm cup of tea" being an indicator. Well it's more like a fresh cup of tea, I can hold my hand on it for a couple of seconds before it feels too hot to grab.

 

I am pretty sure I will just need to repack it now as it is the same packing that was in there (new) when I bought the boat, about 5 years ago. However, I literally can't afford the few quid I need to get the packing for at least a few weeks.

 

My questions are, is this likely to be bad enough to damage my prop shaft if it remains like so for the next couple of cruises and secondly (and more importantly) is there anything I can do to correct it even temporarily until I can afford some new packing?

 

If I loosen the bolts now, the fitting just slides out there is no "spring" left in the packing. I was wondering if I could loosen it slightly, run it in gear and try to "push" the packing back out? Could this work, or is it likely it has just gone hard and useless now and will stay like it is.

I'd slacken it off a bit even if it does drip a bit. If the the engine tends to stall when putting it in gear then so are the gearbox clutches getting punished. You may have forced a strand or two of packing between the shaft and gland bearing which would be difficult to release. Never overtighten them.

  • Greenie 1
Link to comment
Share on other sites

55 minutes ago, DrunkenDonkey said:

Hi  guys,

 

Can't post a picture at the moment, but I have one of those basic packing glands with a bolted in piece that needs tightening up every now and then to push the packing down.

 

The other day I tightened it up and have gone too far as I now have no drip whatsoever, whether in gear or not. I also now have to give the engine a really good rev when it first goes into gear or it stalls, so I'm guessing the prop is so tight it slips on the gears.

 

On the other hand, I can still turn it by hand relatively easily and it doesn't get REALLY hot. I mean it feels probably too hot. I have seen a "warm cup of tea" being an indicator. Well it's more like a fresh cup of tea, I can hold my hand on it for a couple of seconds before it feels too hot to grab.

 

I am pretty sure I will just need to repack it now as it is the same packing that was in there (new) when I bought the boat, about 5 years ago. However, I literally can't afford the few quid I need to get the packing for at least a few weeks.

 

My questions are, is this likely to be bad enough to damage my prop shaft if it remains like so for the next couple of cruises and secondly (and more importantly) is there anything I can do to correct it even temporarily until I can afford some new packing?

 

If I loosen the bolts now, the fitting just slides out there is no "spring" left in the packing. I was wondering if I could loosen it slightly, run it in gear and try to "push" the packing back out? Could this work, or is it likely it has just gone hard and useless now and will stay like it is.

Sadly I think you probably know the answer - you need to repack - may not need to remove it unless its burnt hard or there is no capacity left in the threads but you will need to take a view the packing must be flexible/soft.

NOT good news if its so tight it stalls the engine as it stresses other parts and can at worst distort the shaft - don't beat yourself up this is a trial and error job but caution is always best 

We've all been there - if you aren't confident then pay someone and learn from watching them for next time.

Link to comment
Share on other sites

Thanks for the responses guys.

 

I'd be lying if I said I wasn't a little bit nervous about repacking it, but I'm happy to give it a shot. I'm more worried about the interim few weeks before I can get the bits I need to do it. Yes, I'm concerned about the gearbox as well as the prop shaft. I will have to move along again at least once before next pay day.

 

I don't think the packing has gotten itself stuck anywhere, just a feeling, as if I put it in gear with even a tiny bit more than tickover, it doesn't stall and after it has run in gear for even a few seconds, I can take it out of gear and back in no problem, so to me that seems more like it's a little bit tight and maybe I have been overcompensating with the grease. As the grease warms up it loosesns a bit and it's fine.

 

I was hoping there would be some trick to make it expand again, but I was already leaning towards the old packing having gone stiff :(

Link to comment
Share on other sites

1 minute ago, DrunkenDonkey said:

Thanks for the responses guys.

 

I'd be lying if I said I wasn't a little bit nervous about repacking it, but I'm happy to give it a shot. I'm more worried about the interim few weeks before I can get the bits I need to do it. Yes, I'm concerned about the gearbox as well as the prop shaft. I will have to move along again at least once before next pay day.

 

I don't think the packing has gotten itself stuck anywhere, just a feeling, as if I put it in gear with even a tiny bit more than tickover, it doesn't stall and after it has run in gear for even a few seconds, I can take it out of gear and back in no problem, so to me that seems more like it's a little bit tight and maybe I have been overcompensating with the grease. As the grease warms up it loosesns a bit and it's fine.

 

I was hoping there would be some trick to make it expand again, but I was already leaning towards the old packing having gone stiff :(

As long as you aren't stalling and the shaft is no hotter than tea drinking temp you should be OK you will get a drip so keep an eye on it all until you can resolve.

 

Many of us would be pleased to have the problem highlighted above (sorry couldn't resist!)?

 

 

Link to comment
Share on other sites

No drip at all though! Even in gear, that was what got me concerned in the first place.

 

I have since learnt to read instructions before carrying out procedures. It has only taken me 30 years which is pretty good by male standards I would say.

 

RTFM...

Just now, BWM said:

You have nothing to lose by backing off the two nut 1/2 a turn, run in gear. After a few minutes see what you've got, i am certain the situation won't be any worse.

Thank you, this is what I wanted to hear. Want to give that a go but don't want to make matters worse.

Link to comment
Share on other sites

1 minute ago, Halsey said:

As long as you aren't stalling and the shaft is no hotter than tea drinking temp you should be OK you will get a drip so keep an eye on it all until you can resolve.

 

Many of us would be pleased to have the problem highlighted above (sorry couldn't resist!)?

 

 

You'll need to know what size packing, If an 1.1/2'' shaft 5/16'' is common but there are a couple of other sizes. To find out undo the nuts, withdraw the pusher and measure the thickness of the part that pushes the packing with a ruler or depth gauge.  Do not force oversize packing in it !!

Link to comment
Share on other sites

Quote

 

You've said nothing about pumping some grease in?

Have you tried to grease it at all?  The material is supposed to absorb some grease and that should help to cool it somewhat.

Or am I assume it's another type of bearing, especially as you say the packing is expensive?

Link to comment
Share on other sites

Thanks for that Bizzard, I was going to try measuring outer and inner shafts and subtracting but that is much simpler :D

 

OldGoat, I have been using a lot of grease hoping it might swell it out again, but that doesn't appear to be making any difference. The packing isn't expensive, but I'm totally broke for a couple of weeks unfortunately. It's just normal packing.

Link to comment
Share on other sites

1 hour ago, DrunkenDonkey said:

Thanks for the responses guys.

 

I'd be lying if I said I wasn't a little bit nervous about repacking it, but I'm happy to give it a shot. I'm more worried about the interim few weeks before I can get the bits I need to do it. Yes, I'm concerned about the gearbox as well as the prop shaft. I will have to move along again at least once before next pay day.

 

I don't think the packing has gotten itself stuck anywhere, just a feeling, as if I put it in gear with even a tiny bit more than tickover, it doesn't stall and after it has run in gear for even a few seconds, I can take it out of gear and back in no problem, so to me that seems more like it's a little bit tight and maybe I have been overcompensating with the grease. As the grease warms up it loosesns a bit and it's fine.

 

I was hoping there would be some trick to make it expand again, but I was already leaning towards the old packing having gone stiff :(

If you are only having to move along to comply with the 2 weeks guidance it may be worth contacting CRT and explaining that you have a mechanical problem with the boat that will not prevent you from moving if you have to but that you would prefer to stay put for a few extra days to avoid the risk of permanent damage to the running gear of your boat

Link to comment
Share on other sites

Yeah I have been considering that. I had a really good relationship with the last EO but he has been promoted recently and I have no experience with the new guy at all. Definitely worth a shot though. I mean, I can't afford packing, there's no chance I can dock it and fix a damaged prop shaft or get a reconditioned gearbox!! :D

Link to comment
Share on other sites

1 minute ago, DrunkenDonkey said:

Yeah I have been considering that. I had a really good relationship with the last EO but he has been promoted recently and I have no experience with the new guy at all. Definitely worth a shot though. I mean, I can't afford packing, there's no chance I can dock it and fix a damaged prop shaft or get a reconditioned gearbox!! :D

worth doing it sooner than later, I would think that they would look more favourably on someone that lets them know before they are overstaying and gives a rough date for repairs being complete (+/- a couple of days) than someone that is already overstaying

Link to comment
Share on other sites

This should give you an idea on the price of packing, but of course if you slacken off a bit it may not need doing yet. I couldn't see short lengths at Midland Chandlers web site only reels https://www.asap-supplies.com/propeller-drivetrain/gland-packing-and-removal-tools/prop-shaft-gland-packing

Link to comment
Share on other sites

2 hours ago, DrunkenDonkey said:

Yeah I have been considering that. I had a really good relationship with the last EO but he has been promoted recently and I have no experience with the new guy at all. Definitely worth a shot though. I mean, I can't afford packing, there's no chance I can dock it and fix a damaged prop shaft or get a reconditioned gearbox!! :D

If you don't do something quickly that could well be your next consideration. These things go surprisingly quickly when they go so you need to, at least, back the nuts off a turn or two and put up with the excess dripping. You will need to check your bilge regularly to ensure the water doesn't build up too much. I take it you do not have an automatic bilge pump fitted? That would be a good investment along with the packing when you get some dosh.

Link to comment
Share on other sites

Hi Pete,

 

So the main issue I had was after backing the nuts off, it still wasn't dripping and the pusher could just wiggle back and forth between packing and locknuts. My theory and what I will try next was as BWM had said, to loosen it up a bit but then put it in gear for a bit and see if that brings some water through.

 

I do have an automatic bilge but after a recent engine oil problem I can't turn that on until the oil is cleared. Always something to do...

 

Next paycheck, packing AND oleophilic pads...

Link to comment
Share on other sites

Surely the fact that no water is dripping is not in itself a problem. I have always regarded the drip purely as an indicator that the shaft is not too tight; the ideal situation being that the gland is just, but only just, tight enough to prevent any drips. If the gland does not get hot when running then all is ok.

Link to comment
Share on other sites

28 minutes ago, Keeping Up said:

Surely the fact that no water is dripping is not in itself a problem. I have always regarded the drip purely as an indicator that the shaft is not too tight; the ideal situation being that the gland is just, but only just, tight enough to prevent any drips. If the gland does not get hot when running then all is ok.

except that it currently does get hot (from the OP's description somewhere around 70-75 deg C ) and it is currently tight enough to stall the engine when cold

Link to comment
Share on other sites

18 minutes ago, Jess-- said:

except that it currently does get hot (from the OP's description somewhere around 70-75 deg C ) and it is currently tight enough to stall the engine when cold

At that tightness, I wouldn’t be surprised to find some evidence of wear on the prop shaft where the packing has been rubbing.

Link to comment
Share on other sites

19 hours ago, pete.i said:

If you don't do something quickly that could well be your next consideration. These things go surprisingly quickly when they go so you need to, at least, back the nuts off a turn or two and put up with the excess dripping. You will need to check your bilge regularly to ensure the water doesn't build up too much. I take it you do not have an automatic bilge pump fitted? That would be a good investment along with the packing when you get some dosh.

Backing the nuts off a turn or two would be excessive, 1/2-3/4 of a turn would be ample.

 Don't be concerned if there is no dripping, a drop in temperature and drag on the shaft is all you require. 

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.