My opinion is it is just a waste of grease.
Marine seals, just pack the bearings as normal. Check the temperatures regularly after a long run, if you don't have to, don't back the hubs under cold water whilst still warm, that is the most likely time you will get water in the hubs. (Regardless of whether they are full of something or not, as the contents (be it air oil or grease) will tend to shrink as it cools creating a small vacuum).
You and Aussiebasher have it right, that's what I do, six years since my Dunbier was new, lazy hubs ( 1st to go in water ) are still original set, had to replace front rotors due to rust so they are newer, about 4 years now. I Touch hubs after long drive and Luke warm temp tells me they are still good, I take the bearing buddies off every 6 months or so to inspect, grease is not milky so back on they go without disturbing or blowing dust onto the grease. All good!Originally Posted by Crunchy
Scalem
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I dont use any of the trendy stuff, used BB for a while and they where ok. over 30 odd years of boating reasonably often I have not had a failure and i have done all my bearings myself, surgical cleanliness is the go when fitting, I pack full most of the void full of grease and use a lot of time filling the bearing before fitting and also pack the region between the rear seal and rear bearing till chokers and keep a reasonably thick finger smear of grease at the back of the hub/seal where it meets the axle to ward away potential rusty areas spreading inside the lip of the seal as that has caught me out before as I had to change the axle or potentially not get my 6 years out of the new bearings.
Oh on packing hubs, if a bearing starts to go and this heats the hub past normal op temp, poorly packed hubs have less than 1/10th the watery now leaking/oily grease running around (literally) to keep a level of lubrication happening...the oil in the grease was used up hundreds of km ago in the dryer packed hubs and the bearing has been running metal on metal with only the clay filler component of the grease ever since...guess which one will probably make it home.....on average if tested.
Here's my take for what it's worth...
All seals leak, it's impossible to get a perfect seal on a moving part.
The best defense against water is to have the hub completely full.
The only way to completely fill a hub is with bearing buddys.
If the seal isn't weeping then the hub is not full.
My before and after bearing maintenance which took 30 Seconds with a rag.
IMG_0364.jpg
IMG_0365.jpg
Now here's a picture from a guy who reckoned he had a perfect seal and also used bearing buddys.
axleseal (Small).jpg
My response was, "Your hubs are not yet full".
He still doesn't believe it... *shrug*
I pack mine full and use bearing buddies. My other practice is I replace my bearings every xmas so I know when I did them. 99% of the time they are perfect when I change them. I then recycle the 12 month old bearings into my box trailer and bike trailer. Pretty good turn around and get good useage out of them.
"We gave Howard the Arse now we have to fix Rudd"
"Now we have to sort Gillard" F@?k me RUDD again
Abbott and Newman what a great next few years "NOT"
I used to go through bearings after a couple of outings. Always the bigger inner bearing. Despite bearing buddies. However bearing buddies make the perfect hub cap.
Then I started packing the inner seal (ribs) with grease as well as packing the bearings.
The bearings last for years now.
I usually try to clean and repack them once a year but doesn't always get done. (You can see how things are working if you have a shoofty every now and then.)
Thanks for the replies!! - will keep on top of the bearing buddies with grease and see how things work over time
The finish on one axle flange was pretty poor so might end up tidying that one up next time it's off for checking.
Will also repack the hubs full of grease - more the merrier I reckon!
Durahubs/oil hubs maybe coming when I slowdown spending on the boat itself!!
If you're running the old moving seal type then fit speedi sleeves to it.
http://www.skf.com/au/products/seals...eve/index.html
So if I can ask a stupid question. How do you know if the hub is completely "Full of Grease"???
If you travel that close to the line, one more pump of the grease gun and oops, that's too much now as the grease has popped the inner seal and you may as well start again. Bearing buddies have springs to compensate for the increase and decrease of internal pressure caused by temperature fluctuation. If the hub is too full of grease there will be little room for the spring tension on the backing plate to perform to the way it is designed. I think of it as a shock absorber, the internal design is to cushion impact. Too much grease will inhibit the cushioning of the positive ( when hub warms up while travelling) and negative ( sudden cooling off as the hub enters the water) pressures. When I pack hubs and bearings I probably half fill the hub with grease, no more, so that the air in the hub will help with expansion and contraction as the BB is designed to do.
Scalem
My inner bearing seals let water in.
Found it hard to believe they would not let air (compressed by bearing buddy or heat) out.
However I guess if you have jagged bits with perfect tolerances you might be lucky. I wasn't.
Only issue with that theory (and I don't know the answer) is which one has a greater volume change due to temperature fluctuation. I know air changes volume considerably - put a bit of hot water in a milk bottle, put the lid on and give it a shake - it blows up like a balloon and then sucks back down when it cools. Does anyone have any idea on the volume change with grease over a typical thermal range of a bearing???
I doubt grease changes in volume as it increases in temp and even if it does it would not be more than air to help with the design of the BB which should keep a positive pressure inside the hub.
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And therein is the way they are designed to work Brian.
Any 'pressure', whether +ve or -ve, arises from a change in density of the grease due to temperature changes, and hence the volume 'it wants' to occupy within the hub. Air compresses easily, grease does not - hence (too much grease) popping off inner seals.
The BB/hub is recommended to be charged with grease so that the spring is compressed by half; no more, no less. This then allows the spring to compensate for density/volume changes with the grease, (+ve and -ve), compressing or retracting the spring as required.
'If' I only wanted to half fill my hubs, I would use dust caps (but that's just my opinion). Done this in the past, but then moved on to B/B's, where I used them as above (full hubs, 1/2 spring deflection - wouldn't use them any other way)... but moved on again and would use neither of above again (unless I had to).
If you're happy with how you do it, and more importantly it works well, that's all that matters so just go fishing/boating and enjoy it
Cheers
Brendon
PS. Next meeting is the 2nd Monday (12th Oct), due to public hol, and there is gear/tackle for sale, so bring $'s if you are coming
see previous post (and yes I am a slow thumb typer, so you replied while I was typing
Cheers
So assuming that grease won't change or has a minimal change in volume due to temperature in comparison to air, if you don't want your hubs to suck water past the seals when you dunk them after warming them up ( None of us would sit at the ramp long enough to let them cool properly when we are cracking our necks to get going) then to me it makes sense to fill the hub as best possible with grease through whichever means you choose - manual packing or bearing buddies as against only greasing the bearings and leaving a large volume of air that will contract on cooling and create a suction - sound theory????
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