Upgrading to Front Disc Brakes
on your Herald or Herald 1200

The pages below are taken from the Triumph Herald 1200 Owners Repair Manual; should you ever stumble across one of these, it's an invaluable resource! Click on any of the seven images to see that image full-size. (Sorry, no HTML!)

Note: It is unlikely one would find a complete NOS "kit" such as depicted above. It is far more likely (especially in North America) that one would come across a "donor" Spitfire that could yield most of the basic bits needed. There is no reason I can think of why a Mk3 or later Spitfire, with the larger and easier-to-rebuild Type 14 calipers could not serve as a donor, although the "kit" features the earlier Type 12 caliper of the Spitfire 4 and Mk2.

Key points (in my mind, anyway) are:

• Use of the proper hoses, pipes and brackets for the front brake conversion
  • current part number BPD18 from The Roadster Factory should work for the LH side (original p/n was 132402 and essentially the same part on a Spitfire was original p/n 309701)
  • current part number BPD46 from The Roadster Factory should work for the RH side (original p/n was 305508 and essentially the same part on a Spitfire was original p/n 309700)
  • original caliper brackets may be very difficult to source new or used, but Canley Classics in the UK has reproduced them in alloy. The alternative is to use the later Spitfire vertical links complete with tie rod, etc. Complete assemblies from a Spitfire would, of course, also give you the proper stub axle, wheel hub and -- possibly -- a usable brake disc! You might even get clean, reusable pipes as above from a Spitfire with its origins in a dry climate. (I wouldn't trust old brake lines from the rust belt!)
• Use of the proper master cylinder, with its taller reservoir, or the original with an "extension" on the reservoir and larger-bore rear wheel cylinders. An easy way to "extend" the reservoir on your existing brake master cylinder can be found at Pegasus Auto Racing Supplies and probably elsewhere. Of course, after all this time, there's a pretty good chance your Herald already has the larger wheel cylinders, so it wouldn't hurt to see which ones you have currently:
  • Most 948 Heralds would've had the 5/8" rear wheel cylinder, also shared with Spitfire MkIV and earlier 1500s up to around FH [FM] 80000, and with GT6 from KC7279 through the MkII/GT6+ model
  • Most Vitesse [Sports] 6, later Spitfire 1500 and pre-1973 GT6 Mk3 would've had the .7" rear wheel cylinder
  • Most Herald 1200 and 13/60, Vitesse 2 Litre, Spitfire through the Mk3 and early GT6 "Mk1" would've had the 3/4" rear wheel cylinder.

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4/6/2004; revised 2/22/13