Triumph Repair: 64 Herald 1200 Convertible US, Triumph, Herald

Question
I saw another question from someone with the same car as I am restoring. I need to replace the rear wheel cylinders for the brake repair to be complete. I went to order the parts but found them to come in various sizes. How do these sizes relate and where is the measurement taken from. Was there a standard size during that year? Appreciate the feedback. I have really been trying to get some help via online but the parts dealers never return emails nor answer questions.

Answer
Peter,

Rear wheel cylinders are measured inside the cylinder bore.  Sometimes the size is indicated on the edge of the wheel cylinder near the parking brake linkage.

4 whee drum brake Heralds had a 5/8" bore.  The cars with disc brakes were upsized to a 3/4" rear wheel cylinder bore.

The Spitfire also used similar units and the late Spitfires had an 11/16" bore.

Keep in mind that in the 45 years since the car was built they may have been replaced, and since replacement part supplies were iffy for many years the original units on your car may have been replaced with Spitfire units of any of the 3 sizes.

What you will find is that new units are typically little more than double the price of the repair kit, with the advantage of not needing to mess with cleaning(and possibly honing) the old units.


Cheers,

Jim