Stuffing box packing - When to replace?

[mikecambrai]

You don't mention whether you grease the packing?
Most packing needs to have some form of lubricant and if not it will leak particularly when stationary as when it is running it will expand and not leak.
Packing is so cheap that it is not even worth arguing about.
You can change it in situ if you wish.
I have changed my packing to Goretex as it does not need lubricating and on my shafts, there are no grease nipples.
I don't like teflon seals - just a personal issue based on bad experiences.
Greased wax impregnated seals are long lasting as long as they are greased or have a water coolant fed to them from the engine.
Shaft seals are the simplest and fail-safe system as long as you grease them if they need it and keep them adjusted such that they run slightly warm with perhaps 1 drip per minute, running and none stationary.

[jhulmer]

I would recommend inspecting and maybe changing the pack at least once a year. It's not expensive and fairly easy to do when out of the water.

I removed my prop shaft on my 40 year old boat during refit to find it grooved badly. My research says that this is caused by sand finding its way into the packing and wearing away the shaft over time.

I own a machine and fab shop and I wouldn't attempted to repair this shaft due to the complications of straightening and corrosion resistance of the repair. Others may have had better luck but not me.

I replaced the shaft and installed a dripless shaft seal.

[Brewgyver]

Originally Posted by Nicholson58

(Snip)

BTW, clean the marine growth out of the grooves of the Cutlass bearing with a SS bicycle spoke.

Good idea!

[Cheechako]

If the boat sits a lot, or has sat a lot, often the shaft will corrode inside the stuffing box. Low oxygen and SS dont mix! You can repack, but the corrosion will eat up the packing fairly quick and it's also hard to get it right. Just sayin it might be that. I would say about 50% of the shafts I've pulled on my boats have been corroded as they sit without use for months with a previous owner.
Monel shafts were far superior.

[Cadence]

Packing is cheap, replace it. Especially if you are on the hill that much.

[Wotname]

Originally Posted by Nicholson58

There was no replacing my shaft. Nine feet long, 50 mm and hollow bored for the variable prop pitch controls. It would have been more than $20,000 to replace. I was chief engineer at a large custom machine builder at the time. I put it in our large engine lathe and turned down the packing area and also the heavily worn part at the Cutlass bearing. It was then plasma powder spray welded over sized in both places. Back in the lathe, turned and polished. My only out of pocket cost was the plasma weld, $380.

BTW, clean the marine growth out of the grooves of the Cutlass bearing with a SS bicycle spoke.

Thanks for the explanation of your repair process.

[Sailorbob8599]

I'm surprised there are so many of you using this 'ancient' technology since 'dripless' seals became available a few decades back. I considered the location of my shaft gland nut & realised it was in an almost inaccessible position that would cause a lot of pain & anguish just trying to get down there with an adjusting wrench to try & get the correct amount of 'drip' … so I installed such a dripless sealing system & would never consider a packing gland ever again. So far, it has been absolutely trouble free.