F 100 Brakes for Early Fords by Jim Clark
Early Fords prior to the 1940 models were equipped with mechanically actuated brakes. These were very inefficient even on these underpowered stockers that ran on 2-lane pre-interstate highways at turtle-like speeds. Early hot rodders were quick to adapt the hydraulic systems from the Fords of the forties to the earlier Fords by switching to the later spindles and brake assemblies up front. They were a great improvement but they were difficult to adjust and were not self-energizing. On the later style brakes a star wheel adjusts both shoes at the same time unlike the dual adjusting nuts on the early system. The self-energizing feature, unlike the early Ford brakes which use an attachment point at the bottom of each shoe, are hooked together at the bottom by a spring and adjuster and held to the backing plate by a pin, spring and retainer. This allows them free movement when the brakes are applied. As self-energizing brakes are applied the front shoe makes contact with the revolving drum and tries to rotate it. That movement is transferred through the adjuster to the rear shoe, pushing it into the drum with increased force. Even though the F-100 and early Ford hydraulics share basically the same size shoes the self-energizing feature improves their braking capacity dramatically. By using these early spindles and adapting Ford F-100 pickup brake assemblies and drums both of the problems can be solved.
In the rear the later rear end assemblies were usually substituted for the early rearends. Most hot rods have engine and drivetrain swaps that include the installation of a later rearend assembly. This usually includes the use of the later brake assemblies as well.
Converting to these later front hydraulic brakes on early Ford straight axles or reproductions axles can be a strictly bolt-on procedure requiring no machining or adapters by using nothing but Ford parts. A basic (rat) rod or light-weight early style hot rod will have more than adequate braking capabilities with these drum brakes. Expensive disc-brake conversions on one of these cars may supply more stopping power than desired. Discs only offer resistance to fade in extreme use such as racing and for the traditional look to be achieved the discs have to be concealed inside fake drum assemblies. So you may want to consider this simpler alternative.
All that is used in this conversion from the early Ford system is the spindle from either the '37-'41 or '42-'48. The '37-'41 spindle has a round flange and uses a slightly shorter kingpin (5.480 inches long). The '42-'48 spindle has a square backing plate mounting flange and uses a longer kingpin (5.960 inches long). Either will work with the F-100 brake assembly.
The only modification necessary on the spindle is the grinding of the kingpin boss to provide clearance for the wheel cylinder.
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At top are the F-100 seal, inner bearing and cup. Below are the new seal, inner bearing and
same F-100 cup.
The Ford spindle has a rounded radius where the bearing seats so the inner edge of the
bearing needs to be ground with a die grinder to match the radius on the spindle or the
bearing will not seat fully.
The high angle photo of the spindle shows the gap between the bearing and spindle
mating surface. The bearing should be wrapped with tape to keep out contamination
while the desired radius is created inside the edge of the inner bearing with a die grinder.
Stock bearing is on the left; ground bearing with the new radius is on the right.
Shown here is the finished swap minus the drum.
F-100 drum has a relatively flat wheel mounting surface allowing the wheels
to fit over the drum rather than creating the drastic offset seen when small
wheels are mounted on many other front brake conversions.
Update: Kipp Hansen sends in this question: "What year did Ford make the self adjusting brakes that will fit on the mentioned spindles?"
Answer: The Ford F-100 pickup brake assemblies from model year 1953 through 1956 will work. The brake drums are the same from model year 1953 through 1963 but there are differences in the backing plates, however they might work with minor modifications. The only additional parts needed for the conversion are the new inner bearings and seals. Early Fords and F-100s use the same outer bearings and cups (Timken 09067 bearing, Timken 09195 cup) but the inner bearings are different. F-100 spindles are larger in diameter in the area of the inner bearing, so for this swap a bearing with a smaller inside diameter than the one on an early Ford is required. The replacement bearing needed is Timken number 14116. Its inside diameter matches that of the early Ford spindle with the correct outside diameter for the F-100 hubs. The stock F-100 inner cup (Timken 14276) is used with a Victor seal 49195, or National seal 450461.