If you've got a spare drum, with a set of bearings already in, ready to go, just in case (which is definitely the right move), then hopefully you won't need a hub puller to get the drum off.
The thread Peter was talking about is here: http://www.rib.net/forum/f49/changing-a-set-of-sealed-for-life-bearings-46903.html
It shows how to remove and install a set of "sealed for life" bearings.
I had a message from Steve (the chap who owns the rig and generously allowed me to post the pics in the first instance) and he said he's covered around 5000, carefree, miles in the year or so that I did the service. Which is great news for both of us
If push comes to shove you can definitely change a set with a hammer and socket, at the side of the road. If you're blessed with hefty forearms it doesn't take long at all. What you will struggle with is the retaining circlip, if it's rusted in. They can be a complete PITA and take some effort to remove if rust has got hold. Ensure you remove it too - I remember getting a call from the depot of our largest, national, trailer company who'd try to press a set out with out taking the circlip out first. They'd got themselves in a right pickle and asked me to come and sort it out for them. Personally I'd have just binned the drum and put a new one on, as you don't the stresses you've put on the casting doing something like that. Each to their own I guess. Buy some decent
, large, circlip pliers if you're going to do this (mine are Snap On jobbies, but there's other good ones out there). Don't be tempted to buy thin, cheap, ones as you'll find out, on their first use, that'll the nibs will bend because they're made of plasticine and fairy dust.
Anyhow, I digress, apologies! I've had my hub pullers for years. I've got a few - one huge one that weighs over 30kg on it's own (nothing's defeated it yet
) but if I was to buy another it'd be this, as it's what I already use regularly and is fantastic:
Not cheap (around £200 ish), but I don't buy cheap tools, as I can't afford for them to fail if I'm on a job. However, I've seen them on ebay, second hand, for around £50 from time to time - well worth the investment for someone inclined to tinker with their trailer. Additionally, you'll find you'll become everyone's best mate very quickly...
buy one of these, or similar style, as even if the PCD is attainable, you'll find it's too narrow for a trailer drum's centre boss:
Something like this looks like it might do the trick, but you'd want to check the PCDs it covers:
So, if you wanted to change a drum yourself (with bearings already fitted), you'd likely need:
1. A 3/4" ratcheting torque wrench with a rating of at least 280Nm
2. A good size lump hammer
3. A decent trolley jack - mine's a 3.5 ton job and a (or pair of) axle stand
4. Emery roll
5. A new hub nut
6. Correct size sockets for hub nut and wheel bolts/nuts
7. Rag (all jobs require a rag - hang it out your back pocket, this will ensure that anyone watching will know you're a professional)
To do it:
1. Immobilise trailer, to negate it rolling when you've one side in the air
2. Loosen the wheel bolts/nuts (harder to do when it's in the air)
3. Jack the side up in to the air and stick an axle stand under there too
4. Spin the wheel, to make sure the brake shoes aren't stuck to the drum
5. Remove the wheel
6. Remove the dust the cap
7. Undo the hub nut (using the 3/4" torque wrench)
8. Thump the drum (using your lump hammer). Noise is mandatory - again it shows how professional you are
9. Remove the drum
10. Use the emery on the stub axle, to remove any lips created by the old drum bearing
11. Wipe the stub with your professionals rag
12. Fit the new drum - may need tapping on with your lump hammer
13. Fit new hub nut
14. Torque it up - usually 240Nm
15. Re-fit dust cap - trusty lump hammer again
16. Re-fit the wheel
17. Remove the axle stand and drop on to the deck
18. Torque up the wheel bolts / nuts
19. Stand back and admire your work
20. Wipe hands on your rag (dirtiness of hands is immaterial, again this is for the benefit of onlookers, now in awe of your superior man-skills)
Should take you around 10mins a side. All the best.