How to convert your early cab to accept modern brake master cylinder

[Tx Firefighter]

I took some pictures today as I worked on my truck. It's too hot to work now, so I figured i would do a little tech piece for anyone who has an early cab and wants modern brakes.

My cab is a 62 model. It's the one that takes the dual master cylinder and clutch cylinder combo. I am running a turbo 350 trans now, so I have no need for the clutch part of the deal.

Problem is, the early cabs use a funny diagonal bolt pattern and later model master cylinders use a horizontal bolt pattern.

First, this is the beginning before teardown...


Once the old dual master cylinder combo is removed, you are left with this. None of the holes are conducive to modern units...


This is a later cab (a 63). Notice that along with the funny diagonal hole pattern, there is the horizontal pattern we want...


First, we need to weld up all of the unnecessary holes. Just leave the 4 pictured here. Notice I painted the firewall between pictures, but it's the same early cab as the first picture...


So, I removed the brake pedal box from a later model cab, cleaned it up, and fit it to my early cab. The later pedal box is a straight bolt in other than a tiny bit of grinding needed around the old clutch hole. You can see in this inside shot where I had welded a round patch into the old clutch hole. You will need to grind a bit on the little lip around the old hole...


Outside pic, note the newer box bolts into the same 4 holes we left...


Go back inside and backdrill the two horizontal master cylinder holes, through the bracket and through the firewall. Here is a punch in one of the spots...


The other hole that needs backdrilled...


Now, all you have to do is bolt the later model master cylinder into place and you're ready for disc brakes..


No real money spent on this deal. In my eyes, this is much better than ordering a kit from some place.