Anyone know their maths?

[louis356]

I need to look at my rear wheel bearing and have to take off the 'big nut'

Getting it off should be fairly easy ! but when it comes to putting it back together I'm worried about not torquing it up enough.

I have just bought a meter long breaker bar from an auction and was wandering how I calculate, length of breaker bar, weight of me! (I must admit, I should be taller than my weight suggests. I recon about 12 foot tall!... OK I'm chunky!) to get the required 400lbs?

Do I just stand on the end of the bar until it stops moving? I've also heard of placing oil/ grease to lessen the friction on the Nut / washer.

Thanks

[hot66]

Its early on Sunday, so hopefully this is correct :

I always use a length of scaffold tube on my breaker bar .. slide it all the way along then mark on it where I need to apply my weight.

if the bar was 1ft long, you need a weight of 400lbs on the end of it

2ft long & 200lbs etc etc ..

so , work out how much you weigh and how much length of scaffold pole you need

400 Lbft = 55.3Kg M

so if you weigh 55 Kg, stand on the bar 1meter along

110 Kg weight , then 0.5M along

to work out from your own weight , take the 55.3 , divide by your Kg weight & that should give you the length along the bar in M .. eg if you weigh 80Kg, 55.3/80=0.69M

80Kg x 0.69M = 55.2 KgM



The other way is to stand on a set of weight scales & lift the breaker bar upwards, measuring how much your 'weight' increases by ... if you hold the breaker bar 1 meter away from the nut, then lift the bar and see your weight increase by 10 kg, then you are applying in theory 10KgM of torque

[mycar]

And don`t use grease or oil, it gives you a false reading.

Regards, Mike.

[louis356]

Wow

Thanks for the quick replies guys. Looks like I'll need a 10 cm breaker bar with my weight!

Will get up to the bathroom now and weigh myself and work it out.

Thanks again.

[roy mawbey]

Louis,

!). Try to support the 36mm socket under a axle stand not resting on it but just touching it so that the socket and breaker bar stay in place. If it slips off (which it shouldn't by the way) it might hurt your leg.

Porsche had a special tool that connected to the wheel drum studs and enabled the removal socket to stay horizontal.

2). If you weigh say 13 stone then multiply that by 14 ( 14lbs in 1 Stone ) = 182 lbs.

3). So divide 400 ft pounds by 182lbs and you get 2.197. If you then measure and mark the breaker pole at a length of 2.2 feet, that equates to the 400ft lbs. ( Or I hope it does and don't ask me for it in kilograms I am old fashioned on weights )
4). I would not apply grease to the washer. I do apply a very small amount of copper grease to the thread.

The foot poundage I use is 350 but 400 - 450 even seems now the favoured value. I sort of put by weight with one foot on the pole in the middle of the mark you have made.

Always put the pressure on and do not back the torqued pressure off unless removing the nut completely. I always as a guide mark every thing with a magic marker in the original position before starting by marking the nut and the drum and splitpin hole.

Also use a new split pin the old one has been bent! Also how the split pin is bent over the nut face and over the shaft end.

Roy Just seen you have other answers!! I add mine as it seems to agree with those above.

[mycar]

This is what 400 foot pounds looks like.





Get on.

Mike.

[Burma-Shave]

LOL, have you considered having him calibrated?

100 ft pounds

250 ft pounds

and...400 ft pounds*


* this last value might be accompanied by a gnnnn...yaFUKA sound.

[louis356]

Thank you. A picture says a thousand words alright!

[cubist]

Have always locked the hub up tight by hand with a metre bar then dropped it off the jack, metre bar against the floor and reversed the car half a metre... have never had a problem on bugs, splits and a good few 356s. Agricultural, utterly wrong but very effective in my experience.

[58A - 71E]

Ah those photos...
Carefully measured so that the gut was in exactly the right place on the bar I hasten to say....oh and the last picture is the face you need just before inducing a hernia; don't overdo it mind or you may loose control of several parts of your body that you'd prefer to keep closed....