Manual Brake Input Rod Differences

by George Nenadovich


Here are two manual brake input rods for GM cars. The top manual brake input rod is for 70 and earlier models that have the master cylinder with a deep counter bore. The lower rod is for 71-2 models that use the master cylinder with the shallow depression/countersink. The upper rod overall length is 6 inches while the lower rod is 4 inches....this does not include the "fork"

Here is a close up of the lower manual brake rod...notice there is a metal cup and the rod end is flared. The metal cup maintains the rod in the firewall opening.....keeps it centered and it can not fall out. The top rod does not have this feature because the deep counterbore in the master cylinder keeps the rod in position. You can not interchange the two rods.

Here is a new master cylinder (rectangular style...not the "bath tub" style) Notice the countersink is very shallow.....the shorter manual brake rod goes with this master cylinder.