Confused on parts

[eclipse_22]

I am currently searching for rear wheel cylinders for my 1962 mercedes 190c vin# 11001010018238. Apparently there is one with a diameter of 19.05mm and one that is 23.81mm. Which one do i need? Also what does this diameter mesure? Is it the piston? thanks!

[KCM]

There are two different sizes used on the early cars. W110.010 (190c) chassis used the 23.81 mm up to serial number 064105 with a few exceptions. The 19.05 mm was used after that. The change might have been when they went to front disc (and power) brakes, but not sure. From the VIN number, looks like you have the earlier 23.81 mm, which can be measured from the piston diameter, or the cylinder bore. Here are the part numbers:

Wheel cylinder, 23.81 mm: 001 420 04 18
Wheel cylinder, 19.05mm: 002 420 49 18
Repair kit, 23.81 mm: 001 586 93 42
Repair kit, 19.05 mm: 000 586 12 42

I priced the wheel cylinders and kits for the 19.05 version (3/4" diameter) and found the prices outrageous. Since my cylinder was good, I found a universal repair kit from a 4x4 parts place for a few dollars and just rebuilt the cylinder. 23.81 mm is actually 15/16", which is also a common size, so a repair kit should be easy to find.