Front hub issues

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Dave Woodward
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Front hub issues

Post by Dave Woodward »

For a little while now I've had a vibration under braking that I've been meaning to investigate. I was aware that there was excessive washout on the front offside rotor and so finally have dismantled the offside hub to investigate further. I thought I would share the pictures to solicit opinion.

On dismantling the hub, there was certainly no shortage of grease which had been one of the things on my mind.
The inner race was clean and rotated smoothly.
The outer race however felt gritty when rotating by hand, and ...
The shims showed dramatic signs of disintegrations ...

Overall components - note the row of shims showing fragmentation and splinters:
IMG_4051.JPG
Close up of two shims, showing 'peeling' and 'circular erosion':
IMG_4052.JPG
And two more shims, one appearing to have been 'nibbled' and showing heat discolouration:
IMG_4053.JPG
Happy days!
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clive
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Re: Front hub issues

Post by clive »

Hi Dave,

That looks to be a lot of shims! Did you set it up correctly when you first built the suspension, or did you just use all the shims you had? The shims are different thickness so you can adjust the end float to the required specification by altering the number/thickness of shims.

Andy's video explains it.

https://www.youtube.com/watch?v=NIAfepR5VbM&t=37s
Cheers, Clive.

(If I'm not here I'm in my workshop or on the golf course!)
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amulheirn
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Re: Front hub issues

Post by amulheirn »

Interesting effects on your shims! I don't have many ideas as to the cause unfortunately.

I guess we don't know the original thickness of the shims because they're so worn - I suppose the quantity used might be just that whoever built the hub up only had a larger number of very thin shims.

I found myself having to put a lot of shims in on one hub. Took it apart and boshed the two bevelled rings that the bearings go into a bit further into the hub, then reassembled. Needed many fewer the second time around, so must have been not quite driven home enough.

One question - the shims were in the right position were they? I.e. in-between the small end of the conical spacer and the small side of the outer bearing?

Andy

(Edited to remove a statement I wasn’t quite sure about in retrospect)
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StewbieC
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Re: Front hub issues

Post by StewbieC »

Hi Dave, it looks like one of the the bearings has locked up and those shims have spun to look like that. If the shims have got hot that pretty much confirms the diagnosis. Good that you have taken the time to strip it down and check.
Any time people have a gritty bearing it needs to be replaced as these sit under a pretty heavy load. The MGB set up is pretty durable when done correctly. I like the John Twist video from University Motors as he explains the concept well with having the bearing, shim and spacer "pack" in tension which makes the overall stub shaft and pack combination very strong.

The main thing is the castellated nut must be torqued up to the correct torque and the wheel needs to spin freely without excessive end float. It can take some time to get this right as you can't simply back off until the split pin fits into the hole. You need to take the hub assembly apart and add an additional shim so the torque is correct and the split pin hole lines up with the nut if you torque up and the wheel locks up then an additional shim is require. If you torque up and the wheel turns freely but there is excessive end float, then a shim needs to be removed.
When set up correctly with a good quality bearing (I prefer Timken, NTN, SKF, Fag or another decent Japenese brand) the front wheel bearings should do 20,000 miles (much more if used more frequently as bearings don't like being sat around for long periods of time). Good luck and give me a bell if you need anything.
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Dave Woodward
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Re: Front hub issues

Post by Dave Woodward »

Thanks for the comments.

@Clive: Er no I didn't just use all the shims in the pack. Cheeky :lol: I believe that the assembly was shimmed and torqued correctly at the time but clearly something was not quite right.

Going to check the nearside later today but no concerning symptoms on that side so hopefully not expecting to find anything.

Then to remove both stub axle assemblies and perform a clean and inspection, shopping list and rebuild. All good clean fun.
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nikbj68
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Re: Front hub issues

Post by nikbj68 »

Glad you have ripped it to bits now, rather than suffering a similar fate to Clive & myself( and Mum, of course!)
Clocked up over 5,000 miles since rebuilding ours, and just prior to MOT in July, everything was in A1 state.
I thought it was important to set the endfloat with the entire assembly dry, so that there was no 'take up of slack' by grease, and 'snugging down' bearings & spacers too.
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clive
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Re: Front hub issues

Post by clive »

Don't worry Dave, you can still drive on three wheels!!! https://www.youtube.com/watch?v=ncE3D_fANoU
Cheers, Clive.

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