Page 2 - Valve Identification Guide

Remember most of these cars are over 30 years old and parts have been changed, just because the car has disc
brakes does not mean they are factory.

In 1967 all cars went to dual masters and disc brakes was an option. 1966 and older cars had a single master with
drum brakes. On the right is the 1966 distribution block that can not be up graded to the dual master because there is
no inlet for the second master cylinder line. The block on the left is also a distribution block but for the 1967 dual
master cylinder. It does have the prevision for the second master line but can not be used on disc brakes alone
because it does not proportion any fluid it is still just a distribution block but now has a low pressure warning light
lead. This light comes on in the dash when low pressure is detected.

In 1967 when disc brakes were ordered it received the same brass block to the left as the drum car but had an
additional hold off valve that is to the right. The function of this valve is to apply the rear brakes until the system built
up pressure to activate the valve applying pressure to the front brakes. The rear brakes were to come on a split
second before the front. This brake method soon caused braking problems that took years to solve. The largest
problem was the car had uneven braking causing the car to want to slide out, just like doing donuts with the parking
brake cables applied on front wheel drive cars. This is great fun in a parking lot with no other cars or obstacles
around but not on the highway.

These hold off valves were used on 1967-70 disc cars and changed just about every year. Starting on the left is the
67-68 valve ,the middle valve is the 69 valve, and the right valve is off the 70 cars. Notice the fittings change on the
valves so they will not work with the brake lines from different year cars. It is important to note these valve are not
available new, the ones with the large nut can be rebuild but it often costs more than going to the later 71-72 valve
that Inline Tube offers new.

V a l v e I d e n t i f i c a t i o n P a g e 2 | 4