Brake Master to Booster: On or In?

[WeaselWerks]

I have a hydraulic brake booster that's 'supposed' to be from a K2500 series diesel. The master cylinder that was supposed to go with it won't fit with it's ears flush on the booster. I ground down the master to make it fit flush, but now the replacement master I picked up has the same problem. (I specifically asked the parts counter for diesel master cylinder) Is the inner bore on the JD6 / JD7 hydraulic boosters a different diameter? Or is the master supposed to sit on the 3/4" lip behind the ears? The booster inner bore is 1-11/16" and the booster outer diameter is 1-15/16"

What gives? :confused:

[DmaxMaverick]

The mounting tabs should mate. No gap. Your problem isn't the MC, it's the booster. Probably from an early 1/2 ton, which had a smaller diameter bore to match the early 1/2 ton MC. RWAL and non RWAL were also different.

[WeaselWerks]

Thanks DMax, I figured as much. Now to find a bigger booster. No sense in downgrading the master. :rolleyes: