Mr Blue Sky Posted May 9, 2020 Report Share Posted May 9, 2020 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 Quote Link to post Share on other sites
BlueTR3A-5EKT Posted May 9, 2020 Report Share Posted May 9, 2020 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 Quote Link to post Share on other sites
Mr Blue Sky Posted May 10, 2020 Author Report Share Posted May 10, 2020 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, Quote Link to post Share on other sites
stuart Posted May 10, 2020 Report Share Posted May 10, 2020 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. Quote Link to post Share on other sites
Mr Blue Sky Posted May 10, 2020 Author Report Share Posted May 10, 2020 Stuart, these are 10" 'Alfins' not the 9" version, sorry, should have made that clear. Regards, Quote Link to post Share on other sites
stuart Posted May 11, 2020 Report Share Posted May 11, 2020 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. Quote Link to post Share on other sites
Mr Blue Sky Posted May 16, 2020 Author Report Share Posted May 16, 2020 Hi Stuart, I spoke to the manufacturer and they agreed the run-out was too much and they are taking them back. Currently waiting for them to be picked up. Regards, Quote Link to post Share on other sites
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