Rear axle end float

Post by **Dru** » Sat Jul 11, 2009 11:47 am

...or whatever it's called

I replaced one of the rear hub bearings a while back, as it was a bit deficient in the number of balls it had, and the oil seal was wrecked too as part of the collateral damage...

Anyway, I went back into the hub yesterday to see how it was settling down. There was a bit of float on the hub- that is to say, it could slide inward and outward rather a lot. The Workshop Manual says that the bearing should protrude beyond the face of the hub; in fact, it was about 1mm below the face, which felt like quite a lot when I rocked it to and fro.

So I dismantled it again.

I got some heavy cartridge paper and measured the combined thickness of ten sheets. This gave me 3.5mm. So I reckoned that three thicknesses would be about right. I drew around the bearing and cut out three paper shims, like this

<a href="http://www.flickr.com/photos/belvedere/3706151163/" title="shimming a bearing by Dru Marland, on Flickr"><img src="http://farm3.static.flickr.com/2482/370 ... 3b78f3.jpg" width="500" height="429" alt="shimming a bearing" /></a>

According to my calculations, the bearing face is about 0.5 mm proud of the hub face, and the book says it should be 0.025 to 0.102 mm. I'm hoping that the fudge factor will take the discrepancy on board. And I'll check it again next week or so, to make sure that it isn't leaking.

Do you suppose I was worrying needlessly?

Post by **les** » Sat Jul 11, 2009 9:42 pm

Get another hub, or/and check you have the same size bearing that came out. I'd worry!

Post by **Dru** » Sun Jul 12, 2009 6:33 am

Thanks, Les. Worry mode *on*

It's odd that the book gives the tolerances for the bearing position like that, but doesn't tell you what to do if it is out of spec. I'll check the relative dimensions of the old and new bearings next time I open it up...

Post by **Alec** » Sun Jul 12, 2009 8:34 am

Hello Dru,

I don't like the idea of the cardboard, for as it compacts and or breaks up, this loosens the wheel nuts as essentially they are what keep the half shaft in place. The two screws merely retain it. If the hub is worn but sound, it would be much more reliable to use shim steel. It sounds as if you have a requirement for 0.6mm shimming to get the bearing just proud. You can buy packs of different thickness shim steel and thin shims can even be cut with scissors.

Alec

Post by **bmcecosse** » Sun Jul 12, 2009 10:13 am

I seem to remember the hub is designed to have some built-in end float - although this does sound excessive. If you swop it to the other side - is the float the same ? Certainly cardboard is for gasket material - nothing else!

Post by **Dru** » Sun Jul 12, 2009 6:18 pm

Thank you for providing food for thought

I opened it up again today, and gave it a serious looking at. My measurement of the bearing level yesterday was wrong; I guess it was because I didn't take into account the thickness of the o ring, or something.

So I ditched the paper shims, and rebuilt the hub, and checked the end float again AFTER I'd tightened up the half shaft onto the hub and then the drum onto the half shaft. And there was a little bit of end float, but it felt like an acceptable and useful amount to have. So I am happy again.

What have I learned from this? Hmm, keep asking questions, probably.

Post by **bmcecosse** » Sun Jul 12, 2009 8:49 pm

Or simply - Si fractum non sit - noli id reficere!

Post by **les** » Sun Jul 12, 2009 9:23 pm

Glad things are looking better Dru.
Must learn some latin---won't be able to use this board soon!

Post by **bmcecosse** » Sun Jul 12, 2009 9:27 pm

Dear oh dear - Edukashun these days is not what it was!!
Just paste the Latin into Google.

If it's not broken - don't fix it!

Post by **Dru** » Sun Jul 12, 2009 9:28 pm

I think I know enough engineering to know a rather robust Anglo Saxon version of that one....

Post by **les** » Sun Jul 12, 2009 10:07 pm

If it's not broken - don't fix it!

There you are, good old english didn't hurt after all!

Post by **bmcecosse** » Sun Jul 12, 2009 10:25 pm

Ahh - but Mottos have be in Latin !

Post by **StaffsMoggie** » Sun Jul 12, 2009 11:06 pm

Very true. Latin is a magnificent language.

Acta non verba.

Amor est vitae essentia

Amor vincit omnia

Absit invidia......

Post by **bmcecosse** » Sun Jul 12, 2009 11:15 pm

Hmm -our skool motto was 'Labor Omnia Vincit' - so I suspect above should be 'Amor Omnia Vincit'. Was never convinced about the skool motto either .......

Post by **StaffsMoggie** » Sun Jul 12, 2009 11:27 pm

You are probably right, have a browse through this lot....

http://www.angelfire.com/empire/martian ... asesA.html

Post by **Dru** » Mon Jul 13, 2009 5:09 am

You can be relatively free with the order of words in latin, because the endings of the words tell you which is the subject and which the object and so on. So I think they just plonked them down in an order that sounded nice.

My school motto was 'ex terra lucem', or 'light from the earth'. Perhaps a reference to the lights on the miners' helmets in the colliery next to the school. Always thought it was a bit of an odd motto, that.

Post by **bmcecosse** » Mon Jul 13, 2009 8:30 am

Is this the most wandered thread yet - I wonder ???????

Post by **Dru** » Mon Jul 13, 2009 8:40 am

this thread has got end float