Martin OD Posted March 8, 2023 Report Share Posted March 8, 2023 Hi All. One of my brake drums is scored and I can't find a new one. What are your thoughts of machining the drums to provide a new smooth surface. Any idea how much metal I can take off. Triumph Vitesses Mk1 2 litre. Link to comment Share on other sites More sharing options...
johny Posted March 9, 2023 Report Share Posted March 9, 2023 Theyre available from most suppliers although are expensive (60 pounds each plus delivery). The problem with machining the old one is finding somewhere with the tools to do it these days as it needs a mandrel to hold it centred on the internal mounting hole. Drums used to be routinely machined but as their cost came down it was no longer worth doing. I did manage to get mine done a few years ago in a workshop where they were prepared to have a go using a large 4 jaw chuck lathe and manually centering the drum which improved them but wasnt perfect. One last spanner in the works is the possibility that any replacement drum might not stay perfectly round either. Cast iron has a tendancy to deform after casting and the blanks should be left months before theyre machined to allow for this. However Im not sure this is the case with all after market replacements so I would consider the condition of your old ones carefully before changing... Link to comment Share on other sites More sharing options...
Martin OD Posted March 9, 2023 Author Report Share Posted March 9, 2023 Hi. Thanks for the info. All suppliers I have seen are out of stock. Link to comment Share on other sites More sharing options...
johny Posted March 9, 2023 Report Share Posted March 9, 2023 sorry youre right, when you look a bit deeper theyre out of stock. Only place I can find them is here but think there must be some mistake with the price😮 Brake drum - Rear brakes - Braking system - Triumph GT6 (1966-1973) - Triumph - British Cars - SC Parts Group Ltd Link to comment Share on other sites More sharing options...
68vitesse Posted March 9, 2023 Report Share Posted March 9, 2023 Have you tried Chic Doig?. Regards Paul Link to comment Share on other sites More sharing options...
Martin OD Posted March 9, 2023 Author Report Share Posted March 9, 2023 No. Do you have his contact details please. Link to comment Share on other sites More sharing options...
68vitesse Posted March 9, 2023 Report Share Posted March 9, 2023 01592 722 999 07858 269096 Spelt the surname wrong, now correct. Link to comment Share on other sites More sharing options...
Pete Lewis Posted March 9, 2023 Report Share Posted March 9, 2023 agree on the machining i bought from a good place two new drums for the 2000 they were really based on a thrupenny bit been held in a chuck andseriously lobed went in the bin on our trucks we kept Qualcast drums outside to normalise for 18 months Pete Link to comment Share on other sites More sharing options...
johny Posted March 9, 2023 Report Share Posted March 9, 2023 Yes Id rather have scored drums than oval ones as you really have to back the shoes off so increasing pedal and hand brake travel☹️ With that lump up front the brakings all on the discs anyway.... Link to comment Share on other sites More sharing options...
Martin OD Posted March 9, 2023 Author Report Share Posted March 9, 2023 The problem is right now the car pulls to the left which is towards the good drum. I can replicate it on the hand brake as well and so it is definitely the drums. The new shoes on the scored drum are only hitting the middle (unscored) part of the drum. I could use it until I wear in the shoes so that it hits all the parts of the drum but that will take a while. Or perhaps I leave the hand brake on when driving 🥴🥴🥴 to wear it in. Oval drums will be a disaster 😕. As an aside I am looking at the front brakes shortly. It has been standing for a while and I need to see how good the fronts are. Link to comment Share on other sites More sharing options...
johny Posted March 9, 2023 Report Share Posted March 9, 2023 Definitely dont overheat the drums as that is a good way to get them oval😂 I would ensure the fronts are good and then, unless dangerous, drive it for a bit as even perfect but new drums and shoes can take a while to settle in.... Link to comment Share on other sites More sharing options...
Pete Lewis Posted March 9, 2023 Report Share Posted March 9, 2023 always worth a check you have not fitted the trailing shoe upside down the square hole for the unused handbrake must be at the bottom on the trailing shoe so many are upsidedown and that upsets drum surface contact Pete 1 Link to comment Share on other sites More sharing options...
Martin OD Posted March 9, 2023 Author Report Share Posted March 9, 2023 No. They are fitted correctly but thanks for the tip. I have seen this done as an apprentice. Link to comment Share on other sites More sharing options...
johny Posted March 9, 2023 Report Share Posted March 9, 2023 Reckon accurate machining wouldnt be difficult using a section of old drive shaft with hub. Bolt the drum on reversed using the wheel studs/nuts and clamp shaft in lathe chuck then skim the minimum to achieve a good surface. It probably should be ground but it'll be an improvement even without that👍 Link to comment Share on other sites More sharing options...
Martin OD Posted March 9, 2023 Author Report Share Posted March 9, 2023 That could work but I need an old driveshaft🥴 Link to comment Share on other sites More sharing options...
Colin Lindsay Posted March 23, 2023 Report Share Posted March 23, 2023 YIKES!! Someone taking advantage of the supposed scarcity... if there is one? Link to comment Share on other sites More sharing options...
johny Posted March 23, 2023 Report Share Posted March 23, 2023 Blimey not surprised at the price as no idea where that has come from if really UK made! Course if the casting hasnt been properly aged it can still go oval in a few months - just in time to be outside of any warranty😁 Link to comment Share on other sites More sharing options...
Iain T Posted March 23, 2023 Report Share Posted March 23, 2023 To be honest it does amaze me the very low price of our discs and drums. It's not as though they make 100,000pa of each part. It sometimes worries me the low price and more often than not low quality of replacement safety parts. Iain Link to comment Share on other sites More sharing options...
johny Posted March 23, 2023 Report Share Posted March 23, 2023 Youre right on Spitfire/Herald repro drums but for some reason Vitesse/GT6 ones are much more expensive and why? Maybe the smaller ones are used on loads of other cars so they sell more, either way the quality is a always risk... Link to comment Share on other sites More sharing options...
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