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Allowable brake drum run out


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Hi All,

does any one have any reliable data on the maximum amount of run-out (eccentricity) that a 10" drum can have?    I have approx 0.012" (0.3mm) on a drum I have and I think that is causing the vibration I am feeling when braking.  I have found some data on a truck brake website that states 0.010" (0.25mm) is the max, but wondered if anyone on the forum had anything better?

Thanks in advance, 

Laurence

p.s. I do have a bit of video footage if anyone wants to see the 'swing' on the dial gauge 

 

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What sort of drums?  Cast iron or Alfin?

Alfin have a nasty habit of cracking the iron liner causing there to be hammering through the brake pedal when brakes are applied.

Peter W

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Hi Peter,

they are a pair of  'brand new' Alfins - 1can be adjusted so that the shoes are just 'kissing' the drum, the other has a definite point in its rotation where the shoes bind so they adjusters have to be eased off an additional click.  I fitted the drum loosely on its screws then got my sone to press hard on the brake pedal to centralise the drum.  I then fitted the screws and wire wheel adapter while maintaining pressure on the pedal.  This has helped, but I still get a vibration through the car.  I think I will have to remove both and send them back to be replaced/re-machined.  

Regards,

 

 

 

 

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4 hours ago, Mr Blue Sky said:

Hi Peter,

they are a pair of  'brand new' Alfins - 1can be adjusted so that the shoes are just 'kissing' the drum, the other has a definite point in its rotation where the shoes bind so they adjusters have to be eased off an additional click.  I fitted the drum loosely on its screws then got my sone to press hard on the brake pedal to centralise the drum.  I then fitted the screws and wire wheel adapter while maintaining pressure on the pedal.  This has helped, but I still get a vibration through the car.  I think I will have to remove both and send them back to be replaced/re-machined.  

Regards,

 

 

 

 

The currently sold repro Alfins are actually for 240z cars with the centre machined out and the stud holes opened up, they arent that clever and apparently in competition they dont last very long.

Stuart.

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16 hours ago, Mr Blue Sky said:

Stuart,

these are 10" 'Alfins' not the 9" version, sorry, should have made that clear.

Regards,

 

 

In that case as theyre new I would be talking to the suppliers about returning them.

Stuart.

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