Originally Posted by Irelands child
I guess I missed this part - while they can be rebuilt, I have a problem using a clunk master cylinder from the junk yard. You are spending thousands to build a car, why cut corners here. Master cylinders are too cheap not to buy new - a new Bendix for an '88 Mustang is $37, the older ('86)version, $43 from Rock Auto Parts while a new '79 Corvette, the usual type used on a rod is $43. Equate your time wandering a salvage yard, plus a kit - dang cheap for a new one. Of course "factory" rebuilts are even cheaper yet. Power boosters, if you even need one for a 2800 pound car, a bit more. I have one in my '31 - I forgot to delete that option, but the brakes seem to work fine with it disconnected. If it craps out - it's gone forever.
I have to agree here that I wouldn't use a Master Cylinder that needed to be rebuilt either for as cheap as they are but in my case trust me I didn't use a quote: clunk master cylinder on my car when building it but I did use one from a 3 year old car at the time back in 1992 basically brand new with only 30,000 miles on the car including the Power Booster attached to it from that '89 Mustang LX I spoke about. Don't know if any of this stuff from the new Mustangs could be used but if so I wouldn't hesitate one bit from using these same parts with very low mileage on them if it would work with your car.