how to properly regrease bearings in a trailer

[columnshift]

I'm aware i've posted some other topics regarding trailers - yes i've towed anywhere up to 7000lbs before - but i've never once had to deal with the maintenance side so i'm totally clueless. :^)


I bought a Harbor Freight 4x8 folding trailer last year (12" rims, 1200lb max rated weight, no ebrakes) which the only parting comment I was told was "the bearing grease in these totally sucks and you probably want to replace it".

Well when I was assembling it I started removing the bearing grease... but then felt like I didn't know what I was doing, realizing it was too late to buy any more that night, and being on a super-compressed time schedule (had to have the trailer on the road hours previously) just used it as was, with about 1/2 or 2/3 the grease in the one side partly removed. I stopped every few hours, it clearly heated up the hub more on that side, wasn't happy about driving under those conditions but was too far behind schedule to mess with it. It was never too hot to touch though, just notably warmer on that side with my cooloff periods.


Mostly I didn't know if i'm supposed to clean the old grease out with a solvent (ie every last trace) and also didn't know the proper way to pack new grease into there to be honest. It seemed like quite a bit of grease was in there from the factory... Nor what grease would count as a good one even!

So can someone please walk me through the For Dummies version. I was told to repack grease every 2000-3000 miles anyways and the last trailer trip put 2000mi on it. What is a GOOD grease to use, whats the right way to clean the old grease out, how much do I put into where (do I shove it in by hand or squeeze it in through that little fitting or both), etc.

 

[Oldtom]

Harbor Freight sells a wheel bearing packer that works in conjunction with a grease gun. I have one and it works well. You can also pack by hand, this is slower but works well and no special equipment needed. There are several Youtube videos on how to pack by hand or with a bearing packer. Either method works well, just be sure you do the following:

Clean all old grease out of the hubs and bearings. Cheap brake cleaner spray works well for this. The spray is flammable so be careful. Mixing old and new grease can cause bearing failure.

Use a grease rated GC-LB. That is the top rating for grease. Brand name does not matter, just use quality grease. Always stick with that brand and do not mix grease.

Adjust the preload on the bearing carefully. See Youtube for how to do this. Hope this helps

 

[Oldtom]

Columnshift - The reason I suggested Youtube videos is visual learning. I have the worst time learning something from reading a manual but can learn quickly watching a video. Maybe that is why school was such a lovely experience I thought of another tip:

Do not "spin dry" the freshly washed bearings with compressed air. The dry bearing will be ruined by spinning it with the air hose. You can hold the bearing tightly and blow any traces of brake kleen away, just do not let the bearing or individual rollers spin.

Hope this helps

 

[RooflessVW]

Diesel or gasoline in a bucket is the best way to clean bearings. Set them in the sun to dry. Hand pack them afterwards and coat the races and spindle with a nice layer. Tighten by hand until you feel them drag and then back off to the install the cotter pin.

 

[SwampSurvivor]

The issue with Youtube videos is pretty much every one I have seen on trailer bearings they skip the inner bearing. That's not good. There's two bearings.

It's quite simple, though.

Just pull the spindle nut (it should not be tight at all) , then take the hub and outer bearing off at once, then the inner bearing will be in there.

I cleaned mine with kerosene, probably not necessary.

There's good videos on how to pack the bearings themselves - that's a good one to watch.

Then put everything back together as it came apart.

I usually put everything together, then tighten the spindle nut (not much!!), then spin the hub to get everything to seat, then back the spindle nut off until it's just touching the hub.

 

[Donald]

You will need a new seal if your going to do inner bearing.

 

[chainblu]

Originally Posted By: Donald
You will need a new seal if your going to do inner bearing.


Good point. Is there a number on the old seal that the guy at NAPA could cross to?

 

[BrocLuno]

OK, it's a newish trailer and the original grease was something... it ran down the road and did not seize up. So pull it apart and look at the bearings. Any score marks, and color change in the metal? Any gritty feeling when they roll?

If all OK, just get a bearing packer and force the new grease through the old. Yeah, some will remain, but it was working so no biggie.

This was a new trailer so I'll bet the seal will still be usable... Do the same for the inner bearing and re-assemble.

The thing that can make a bigger heat difference than the slight lack of grease on one side or the other is the bearing pre-load. That is how tight you crank that nut before you lock it in place?

My uncle (a mechanic/welder) taught me many decades ago to crank it down until the wheel starts to drag when rotating it by hand, then back off 1/8~1/4 turn on the nut and insert the cotter pin. Has worked for me for about 50 years now

 

[columnshift]

Thanks for the specifics... I guess one thing I was confused of was when I saw the original bearing there was a huge glop of seemingly extra just slopped or shoved in there. I know the bearings had grease, i wasnt sure how much more than 'inside the bearing' there should be grease. The overgreased side was cooler on the road.

I'm not even sure what bearing preload is offhand, I can look for a youtube video but short version how is it usually done and verified as correct?

 

[SwampSurvivor]

With my small trailer axle, I just made everything was together and tightened the spindle nut with my hand turning the socket. You don't want it lose, but you don't want any drag, either.

The "grease" on these trailers is just some sort of assembly grease or corrosion prevention grease.

 

[cptbarkey]

Originally Posted By: Miller88
The issue with Youtube videos is pretty much every one I have seen on trailer bearings they skip the inner bearing.


Yeah, suggesting youtube should really be:

watch 4 youtube videos of the same thing.

that way you filter out the chaff of people making the video about themselves versus doing the job.

i'm looking at you eric the car guy.

 

[SwampSurvivor]

I never got into ETCG. Maybe I started watching his videos too late?

Pine Hollow Auto Diagnostic, South Main Auto, Scanner Danner I'm good with. Enjoy those.

 

[sciphi]

All I did with my HF trailer was squirt in real grease until it started oozing out the other side, lol. After realizing there was no way I could get the inner bearing race out with the tools on hand without damaging it, I started pumping in grease with a grease gun. That surprisingly appeared to push out most of the old assembly lube. The zerk is next to the inner bearing, so it gets the inner bearing pretty well. It's been a few years and a few dozen loads later, including lending to friends, without issue. I'll probably re-grease the bearings soon using the same method just to get some fresh grease in there.

 

[supton]

That reminds me, I haven't checked mine in a few years.

On my HF trailer I found that HF had the bearings for it cheapest--NAPA wanted like $20 per bearing, HF wanted $5 per. But this was a decade ago, so prices may have changed. Anyhow, at $5 per I'm not sure I'd clean the bearing; I'd just replace if the grease was all garbage--pretty sure I bought a spare set to sit on the shelf for that purpose. If the grease looks good, then just wipe down a bit, slap some more on, then reinstall.

I had a trailer with those Bearing Buddies on them; after doing much reading I decided I didn't want them. When I removed them I saw that they were pumped to full out. But once removed, I found that grease had not worked its way past the outer bearing to the inner. Maybe it takes some driving to do that, dunno. But I decided that since it wasn't a boat trailer then I really didn't need those; and that I was best off packing by hand, rather than just relying on a zerk fitting.