On November 9, 2005 Tom Jennings wrote: > My rear brakes have been grabby since day #1 (on my 70 Hornet). > Spelunking in my notes I found out why -- the rear wheel cylinders > are .875" (7/8"), for a four-wheel-drum-brake car, and up front I've > got Bendix calipers. (I was gonna go all drum but chickened out and > switched to disks.) > > (Bendix caliper small cars got .8125" (13/16") rear wheel cylinders, > at least 1979 did.) > > That would explain the overactive rear brakes (too much area on rear > pistons). > > But for the record, the 1" drum brake master cylinder, and one- > diaphragm drum brake booster, makes for excellent pedal; plenty of > assist but nowhere near "feather touch". The bigger M.S. bore (1970 > drum 1" vs. 1979 disk brake cars got .945" (24mm) masters) raises > pedal pressure (but lowers travel), a nice match for a modest amount > of boost. > > Yes, I popped out the master cylinder residual-pressure valve for the > front brakes. If the grabby rear brakes bother you just install a Wilwood in line proportional valve in the line out of the master to the rear brakes. I did and set it right in the middle of the adjustment range and never had to touch it. I am using the original 74 drum brake booster and master. Possibly the reason I really did not have to adjust the valve is because the front disc set up came from a 79 Concord and I also installed the complete rear out of the same car. But it was a non power set up when in the Concord. There is nothing like driveing through the hills where I live with out the drum brake fade I had to deal with for 30 years with this car now that it has disc's. "Doc" ============================================================= Posted by wixList Archiver -- http://www.amxfiles.com/wixlist