Bearing pre-load and filling the hub

[Nitrousbird]

As I started repacking bearings this morning, I realized I have never done this job by myself.  I've assisted friends a couple times (many years ago), and might have done it once on a vehicle of mine 15-20 years ago, but never a trailer.  First boat I had for almost 11 years and never touched the bearings and got away with it.  This one had them freshly done by the original owner before purchase and haven't been touched since.  Had made 5 ~1000 mile round trips in the last 7 years, along with our 4 mile round trip to our ramp on the regular.  I already screwed up and forgot to buy new inner hub seals, so I had to way overpay locally.

Two things of concern, as I've done two of them so far...had to stop to do other stuff and will finish tomorrow:

#1:  Bearing pre-load.  I've read everything from 1/4" play to 0 play.  How I did mine was get it seated and spin the hub a bunch back and forth, nudging the hub in and out as well.  Tightened the castle nut (by hand only) until the play just went away.  The hub spun as freely as it did with some play.  Cotter pin hole lined up fine.  

#2:  I used a bearing packer tool (smart move on my part, worked great).  I pre-greased the spindle, hub and rear seal.  I just put the bearing in covered in grease but did not fill the hub further.  Same for the front side.  I do have bearing buddies and pumped them about 1/3 full once everything was reinstalled.  I've read recommendations both ways

- Should I leave my pre-load as is, or back it off 1 notch to get the slightest amount of play?  This can be done with wheels on so not a big deal.
- Should I pull the whole hub assembly to pack it full of grease on the back side or just leave it as-is?

Everything else looked great in the hubs.  Grease was ready for replacement but the bearings/races look mint.  I will get about a 10-15 mile tow maxing at 55MPH prior to a 1000 mile round trip starting next Friday.  I have an infrared gun I will use to check hub temps.

[wakesonthesnake]

I have always done mine as you did.  When I check them after a few hundred miles there is almost always a tiny bit of play by then.  Sounds like you have the right amount of grease to start.  One thing bearing buddies hate is too much grease.

[Nitrousbird]

Finished it up.  When I had a wheel come off last year, I had to have a trailer shop do the repair as we were on the road.  Walking in you could tell this was a good shop (plenty of work, as I had to really plead my case to get him to do the job, super clean/neat place and they knew exactly what they were doing without hesitation).  He had the pre-load set on that wheel tighter than I had it.  Made it a good 700 miles on his work with zero issues; much of that going 70-75MPH.  

Grease wise, I tried back filling additional grease on the rear bearings and couldn't really get any more in.  I think I'm good to go.

[justgary]

I like to set the preload by turning the nut until the wheel is fairly hard to turn and then backing it off until I get a tiny bit of play, then slightly tightening again to just remove that play.  I overtighten while spinning the wheel in an attempt to seat any race that got driven in with a slight angle.  I've done it this way for a very long time. 

Here in salt water, the number one thing is to keep fresh grease on the bearings, so I give the bearing buddies a few pumps before every outing.  Yes, it gets messy as the old grease finds a way out, but I don't have very many bearing problems this way.

[granddaddy55]

The bearing buddy should only be filled/used after a trip of length immediately following your re grease maintenance  to create real heat snd grease expansion ,  not 4 miles?, at the launch start filling the bearing  buddy and stop as soon as you see it move.  Then launch or go home.  Above he is creating his problem by overfilling and when  the grease heats from a real trip , it blows out the rear seal as the mess he is referring to( continued filling as he does is necessary to push out the water broken down grease replacing it with new grease with old broken down squirting out the rear seal as he pushes new in through the buddy fitting)

  Bearing buddies are basically caps that allow that one top off after heat.  When you follow this protocol , you don’t have rear seal leakage or water intrusion because of the blown rear seal 

you have already overfilled yours 

i think the rubber “caps “ sort of help especially when you don’t overfill , hopefully in reducing how much the spring seal gets penetrated especially when it’s not tight/pushed out far from overfilling 

some folks damage rear seal when pressing /tapping that in if it goes in on  angle before it pushes in flat treating it like its the race 

Edited September 16, 2018 by granddaddy55

[Nitrousbird]

Well, my pack job was spot on.  Highest hub temp I measured was 101 degrees with high 80's ambient.  No grease out the back seal either.

[racer808]

I remove any play in the hub.  I left just a little last time & lost 3 bearing buddies.  Might have lost a wheel too if I didn't take it apart, snapped two studs putting the wheel back on so there was a ton of force on that spindle.