Brake Master Cylinder Q

[Ohmess]

Hi All -- Upon returning from the Vintage, I have determined that completing the process of refurbishing my brakes needs to be high on my list.

I intend to rebuild a brake master for my car, and would like to rebuild one of the masters I have laying around rather than the one in the car.

However, RealOEM shows two different size masters for our cars (and for the Bav). In looking at the two masters I have laying around, how do I identify which is a 22.2 mm and which is a 23.81 mm? And if I happen to have one of each, is one preferable to the other?

 

[Stan]

bigger is always better!

 

[lloyd]

Hi All -- Upon returning from the Vintage, I have determined that completing the process of refurbishing my brakes needs to be high on my list.

I intend to rebuild a brake master for my car, and would like to rebuild one of the boosters I have laying around rather than the one in the car.

However, RealOEM shows two different size boosters for our cars (and for the Bav). In looking at the two boosters I have laying around, how do I identify which is a 22.2 mm and which is a 23.81 mm? And if I happen to have one of each, is one preferable to the other?

Um. the dimensions you posted suggest you are describing the inside diameter of brake master cylinders and not boosters. With respect, those differences are negligible and I doubt you would notice one over the other, unless you are an active competitor or you are prepared to accurately measure such things.

Typically, the larger bore equates to greater pedal effort with less pedal travel to produce a given line pressure. Conversely, the smaller bore would require less pedal effort with more pedal travel to equal the same pressure.

 

[HB Chris]

Only the larger one is available. Switch from large to small occurred at 2240222/2250146 when the larger booster also appeared.

 

[Ohmess]

Um. the dimensions you posted suggest you are describing the inside diameter of brake master cylinders and not boosters. With respect, those differences are negligible and I doubt you would notice one over the other, unless you are an active competitor or you are prepared to accurately measure such things.

Typically, the larger bore equates to greater pedal effort with less pedal travel to produce a given line pressure. Conversely, the smaller bore would require less pedal effort with more pedal travel to equal the same pressure.

Lloyd -- I made a mistake in bringing boosters into the discussion; I had intended to speak only of brake master cylinders. I have correct this.

Both the spare masters I have are from cars after the VINs Chris posted, so I conclude they will both be the larger cylinder bores.

 

[HB Chris]

They switched to smaller bores at those vins. I don't think it makes any difference though.

 

[Ohmess]

Oops; misread your post.