Master cylinder problem?

[2rods]

Ordered a master cyl for the surge unit on my car trailer and the cyl bore is supposed to be 1 1/8" but this new one is 1 3/16". This bore is not even listed in the book :?  Anyways will I be OK with a larger bore? The brake pressure will be slightly less with the bigger bore correct? Need help with this asap. Thanks guys.

[enjenjo]

You should be ok, that is less than 5 percent change. you should be able to adjust the spring that much if needed.

[2rods]

What spring are you talking about? Doesn't seem like there is anything to adjust. Thanks.

[enjenjo]

The one I have has a spring over the pushrod that can be adjusted for brake apply force.

[PeterR]

You should be ok, that is less than 5 percent change

Frank, you forgot to square the diameter ratio to give the pressure ratio.  Actual difference is 11%.   But in the end it is of little consequence.  

There will be a 11% greater push on the tow bar, so slightly more of the braking will be done by the tow vehicle, but it is unlikely you will even notice the difference.

Much better to go oversize than undersize and risk running out of stroke.

[enjenjo]

I knew you were going to call me on that Peter LOL. I should have stated 5 percent difference in diameter, I knew the area increase was greater than that.