Order the right size the first time. Follow the pictures.
In short
The size of a brake master cylinder, clutch master cylinder, clutch slave cylinder or wheel cylinder is the inner diameter of the bore (for example 7/8″, 13/16″ or 22.23 mm). Remove the piston and seal, wipe the bore clean, measure the inside diameter at three depths in two directions, take the average and round to the nearest standard size. 1 inch = 25.4 mm. Wheel cylinders are handed, so check LH / RH as well as size.
Not sure? Send a photo with the car model, year and your measurement via LINE @bocbrand or call 02 613 9898 (Mon–Sat 09.30–18.00, closed on public holidays). You can also browse Find by Car or our brake hydraulic cylinders.
