Tight disk brakes - overheat - hard pedal -------------- There is a tiny, (less than .040"), compensating port drilled from the bottom of the resevoir to the master cylinder bore. It's purpose is to let pressure out of the brake lines when the pedal is released. It's drilled in the center of a larger countersink, next to the inlet port, which is about 3/16. Make sure the compensating port is clear with a single strand of copper wire or a needle. My new "Safe Line" master hadn't even been drilled, just countersunk! I couldn't have driven it 2000 miles that way, though. Also make sure the piston unmasks this port when the pedal is released, (push rod free play). There should be a small geyser of fluid from this port into the reservoir when the pedal is first depressed. Watch your paint! I think the hill holder only works on the rear brakes, so it's probably not your problem. The single circuit master I took off my '64, recently, was actually a Plymouth part someone had substituted, in the past. It was made for use with drum brakes, and incorporated a residual pressure valve, a thimble shaped, disc valve, in the very front of the master cylinder bore. This is supposed to keep a few pounds of pressure in the lines to keep cups in position and prevent rattles in a drum brake system; but it should be discarded for use with discs. My front brakes had overheated, but not locked up, with the valve in place. By the way, the Plymouth cylinder looks like the Stude but has a smaller bore. Also, the push rod length must be adjusted shorter. mmudd@erols.com Sep 2001 -------------------------- It could well be that the rod coming out of the vacuum booster is adjested incorrectly--that is, too long. The first thing to do is to check that against the Shop Manual specs. sgundry@aol.com sep 2001 -------------- Adding a split brake MC A dual master with a residual pressure valve on the side for the rear brakes is a good idea. Disc brake Studes used a single circuit master with no residual pressure valve; and I think the seals, in the rear cylinders, get out of position and leak without it. It keeps a little pressure in the lines. Most masters made for drum/disc combinations will have it. Make sure you don't connect the discs to the port with this feature. It will be just like riding the brakes, and they will over heat! I had to shorten the push rod, just a little, to get release clearance. I cut the threaded end and cleaned the threads up. A special plug came with mine; for the unused port on the brake line connector block. Mike ------------------------ Check the bore of the M/C #83014, be sure it is 1 1/32" The BIGGEST thing when swapping out a M/C, is the adjustment on the rod between the booster and the M/C. each M/C has a different length "hole" in the piston, and the rod on the booster (or pedal for non power brakes) needs to be adjusted accordingly! Otherwise, you will have brakes that drag, or a low pedal. Converting to a dual M/C when it's mounted on the firewall is pretty easily done. There is a brass T fitting almost directly below the M/C. Take the line that goes to the rear off, and put a plug in that outlet. Bend the line up towards the M/C (without kinking it) and use a flared union to connect a new line that will come from the FRONT outlet to the rear line. Then run a new line from the REAR outlet to the brass T. Be-sure you have the linkage rod between the booster and M/C adjusted correctly, bleed them and test drive the car. Start with slow speed stops first, then faster "panic" stops. If you did not get the push rod adjusted correctly, it can be done without having to re-bleed the brakes. I think Bob Palma included an article in the April 2001 Co-Operator in Turning Wheels. Most M/C use the port closest to the pedal for the front brakes, and the one farthest away for the rear brakes, better to ASK first, as not only YOU life depends on proper installation and adjustment, but, so does other people on the roads! Jim Turner -----------------------------