Wheel cylinder bore size

[jdl71]

This is a probably a pretty generic question but is there any harm in using one size larger wheel cylinders on the rear? After tearing into my rear brakes I found an 1.25 bore wheel cylinder. The fronts are 1.125 and as is the mc, this is also what is supposed to be in the rear according to the manual. If it's like any other brake part for a 66 K20, finding the correct replacement will likely be a challenge to say the least. I was able to clean up the one I took out so I'm thinking about just going with it. I guess I'm just curious what the result will be. The rear brakes I'm assuming will get a bit more force than the fronts. Will it even be noticeable?

[Captainfab]

Your front brakes are supposed to do the majority of the braking. A 1" bore wheel cylinder would likely be correct.

[69 C10 LWB]

If you are still running the factory single master you may run into an issue. A larger whee cylinder will provide more force to the rear drums and it will also require more fluid for the same amount of movement. This could result in a low pedal or the rear brakes locking up. I would try to find the same size whee cylinder to put back in.

[jdl71]

I guess I'm going to try to find an 1.125, although this is what was in there and I presume it worked at one time. I've only taken one side apart on the rear so I'm curious to see what I find on the other. The service manual says mc and front wheel cylinders should be 1.125, with the rear being 1.13. Not sure exactly what that is, 13/100 doesn't reduce any farther.