Stern tube greaser copper pipe advice please?

[Hairy Animal]

The stern tube greaser that I took off our boat early in our restoration was connected to the stern tube by a length of 3/16" copper pipe via compression fittings at either end. However, the existing pipe is too short for the new location of the greaser so I need to replace the pipe.

 

Does anyone know if I can use 3/16" copper pipe I can buy on eBay that is advertised for use in car braking systems?

 

Thanks.

[RLWP]

Yes

 

I'm surprised it is as small as that, I would have expected a larger diameter. Cold grease is very viscous

 

Richard

[Hairy Animal]

I'm surprised it is as small as that, I would have expected a larger diameter. Cold grease is very viscous

 

Richard

Thanks Richard. Yes, I was surprised by the narrowness of the pipe, especially as it's quite thick walled, but presumably it worked okay in the boat before we bought it and it keeps things simple to use the same pipe size again so that I don't have to change the fittings at both ends. The new position for the greaser will be close to the electric motor which will probably get warm and should therefore keep the greaser warm and the grease a bit more fluid.

[bizzard]

Car hydraulic brake bundy tubing is thick walled and has a very small bore which I think you'll have trouble forcing thick grease through especially in cold weather when the grease is thicker, when it will take quite a time and considerable force to get enough in.

[Hairy Animal]

Yes, I was surprised when I looked at it as well. Photo attached of one end of the pipe. Considering the o/d is less than 5mm it doesn't give much space for the grease to move, but as it seems to have worked before we bought the boat, I'll try it out and see how it works. If it's too difficult, I'll look at replacing the fittings and pipe with a larger diameter.

[bizzard]

Yes, I was surprised when I looked at it as well. Photo attached of one end of the pipe. Considering the o/d is less than 5mm it doesn't give much space for the grease to move, but as it seems to have worked before we bought the boat, I'll try it out and see how it works. If it's too difficult, I'll look at replacing the fittings and pipe with a larger diameter.

Hard plastic-nylon tubing is commonly used these days, normal olives work on it. just don't over tighten.

[blackrose]

Car hydraulic brake bundy tubing is thick walled and has a very small bore which I think you'll have trouble forcing thick grease through especially in cold weather when the grease is thicker, when it will take quite a time and considerable force to get enough in.

Especially since you're lengthening the pipe.

[Dalslandia]

I or the boat have long greese tubes, they are larger then brake lines, 1/4 or so maybe 3/8"

Edited March 5, 2016 by Dalslandia

[MtB]

Yes

 

I'm surprised it is as small as that, I would have expected a larger diameter. Cold grease is very viscous

 

Richard

 

 

And the pressure from the greaser is very high....

 

The small diameter only limits the flow rate, not the pressure. And the stern gland only needs a CC or three every 24hrs...

[alan_fincher]

And the stern gland only needs a CC or three every 24hrs...

For my boats.....

 

"I wish!".

[MtB]

For my boats.....

 

"I wish!".

 

 

Hmmm shirley this is easily fixed? Have you tightened the nuts on the packing glands?

 

Or worst case scenario, replace the packing material?

 

Both my boats use microscopic volumes of stern gland grease.

[RLWP]

 

 

Both my boats use microscopic volumes of stern gland grease.

 

And macroscopic quantities of engine oil?

 

Richard

[Hairy Animal]

And the pressure from the greaser is very high....

 

The small diameter only limits the flow rate, not the pressure. And the stern gland only needs a CC or three every 24hrs...

That's a very good point.

 

I have managed to find a local car spares place with the requisite 3/16" diameter copper pipe for £3 and new olives from eBay for less than £2 so the system should be working again soon. If I'd changed to any other size of copper pipe or nylon pipe, it would have cost much more. The downside will be how long it takes to refill the very long (2 metres or so) stern tube with grease initially, but once done, hopefully it will be easy to top up as required.

 

I expect top-up will depend on how well I've repacked the stuffing gland. As I've never done this before I will be keeping my fingers crossed when the boat goes back in the water, as that will be the most likely source of initial water entry. Fortunately, I have had good guidance on how to do this.

[Hairy Animal]

Using the locally sourced 3/16" pipe and new olives from eBay, I've reinstated the stern tube greaser some three years after I removed it at the beginning of our restoration. Despite the near freezing temperatures this morning, it wasn't difficult to squeeze a bit more grease through the metre of pipe into the stern tube, so all is well and thanks to all for your contributions.

[bizzard]

Using the locally sourced 3/16" pipe and new olives from eBay, I've reinstated the stern tube greaser some three years after I removed it at the beginning of our restoration. Despite the near freezing temperatures this morning, it wasn't difficult to squeeze a bit more grease through the metre of pipe into the stern tube, so all is well and thanks to all for your contributions.

Are you sure the grease has reached the tune gland. If the the greasers piston 0 ring is worn grease can easily squeeze past it and just transfer grease to above the piston. It might be worth unscrewing the greasers top and handle and having a look.