A Little Learning

Cupie · Guru

Servicing Bearings & Brakes

Dav4Cris · Senior Member

Yep agree with that one, so easy to do, just some common sense and time, which we all have?

Brenda and Alan · Guru

A few comments on this article from a lot of years as a mechanic.

Any grease applied into the hub centre is just a waste as it will remain there until cleaned out next service.

Tensioning of wheel bearings is a misnomer as Timken type bearings are designed to run with ZERO preload. It is better to be a bit loose than a bit tight as any preload will shorten bearing life markedly. With the castle nuts used on caravan axles avoid the temptation to tighten the nut in order to fit the splitpin, always loosen it to fit.

Re packing every 10,000 Km is over kill for quality bearings that are properly packed with grease and adjusted correctly, but won't do any harm.

Dougwe · Chief one feather

Just another view from a different angle.

As easy as that all sounds in the link I am one that has never dabbled in that sort of thing so the lack of knowledge and experience stops me from performing such an important item of caravan maintenance. I think I will leave that one for those that are qualified or someone I trust. Not saying you guys don't know what you are doing as you sound like you do, just adding a different view.

Cupie · Guru

Brenda and Alan wrote:
A few comments on this article from a lot of years as a mechanic.
Any grease applied into the hub centre is just a waste as it will remain there until cleaned out next service.
Tensioning of wheel bearings is a misnomer as Timken type bearings are designed to run with ZERO preload. It is better to be a bit loose than a bit tight as any preload will shorten bearing life markedly. With the castle nuts used on caravan axles avoid the temptation to tighten the nut in order to fit the splitpin, always loosen it to fit.
Re packing every 10,000 Km is over kill for quality bearings that are properly packed with grease and adjusted correctly, but won't do any harm.

Alan ...

Of course I bow to your superior knowledge, training & experience as a Mechanic.

I agree that the 10,000 Km is probably an overkill but I have always done so primarily as an insurance. My 1999 21'6" Jayco is still on the original bearings with no sign of wear after at least 200,000 KM. So I must be doing something right.

I have never taken out the inside rollers or seals, I just clean them while still attached to the drum & repack them as best I can. A bit lucky I guess and not to be recommended of course.

After inserting the split pin I fit the wheel & test for top & bottom wheel movement. If none, I loosen the nut off to the next slot & try again, repeating this until I get a barely perceptible movement. After traveling 10 or 20 KM on the next trip I usually pull up & check the wheels for wobble & temperature. Look for excess grease weep too.

After listening to guys like you, I have gradually reduced the amount of grease that I leave around the stub axle. As a young fellow I even filled the grease cap over the castle nut. I do get a bit of grease weep out of the outside of the cap after a regrease. Never anything on the always dry, break linings etc. Lucky again perhaps.

To adjust the breaks, I just wind them right up until I can't turn the wheel, operate the breaks fully on manual over ride on the controller, and them back them off until the wheel turns freely with a faint 'chink , chink' noise as it spins. Then I again apply the breaks & test for chink chink again.

I learnt from backyard mechanics many years ago when we did all of our own mechanical work out of necessity, so certainly don't profess to be expert in these matters and always bow to greater wisdom. Getting to old with failing arm strength to do much these days so I use a local mechanic for most of my mechanical work. Long gone are the days where I would pull down the motor of my old Vanguard & repack the big end bearings progressively with brown paper then shims of brass or perhaps tin cans, even cutting out new oil grooves in the slippers when they got too worn. Cars were much simpler & perhaps forgiving in those days. Calling me a 'bush mechanic' is giving me far too much credit.

The old saying " A little learning is a dangerous thing. Drink deep or taste not the Pierian Springs ... " comes readily to mind and no doubt applies to guys like me..

ps. This is where I stole that wise old saying from .. It has stuck in the back of my mind for decades and pops out as a self alarm when I tackle something that I know only a little about

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A Little Learning

by Alexander Pope

A little learning is a dangerous thing ;

Drink deep, or taste not the Pierian spring :

There shallow draughts intoxicate the brain,

And drinking largely sobers us again.

Fired at first sight with what the Muse imparts,

In fearless youth we tempt the heights of Arts ;

While from the bounded level of our mind

Short views we take, nor see the lengths behind,

But, more advanced, behold with strange surprise

New distant scenes of endless science rise !

So pleased at first the towering Alps we try,

Mount oer the vales, and seem to tread the sky ;

The eternal snows appear already past,

And the first clouds and mountains seem the last ;

But those attained, we tremble to survey

The growing labours of the lengthened way ;

The increasing prospect tires our wandering eyes,

Hill peep oer hills, and Alps on Alps arise !

Brenda and Alan · Guru

Cupie nothing wrong with that method of adjustment. I adjust similarly after seating bearing if new by tightening and loosening. I do it with the wheel on, tighten till play just disappears then back of to split pin hole. Our old Patrol went over 500,000 Km on first set of bearings and were only changed when replacing steering bearings, but would have gone longer.

Alan

03_Troopy · Guru

One thing that surprised me, when he mentions blowing out the bearings with compressed air, he doesn't make the point that you shouldn't spin the bearings with the compressed air.