"Is it possible to upgrade FE-FC front brakes to EJ-EH or HD" is a question which comes up fairly often. The accepted method is to change over to EJ-HD steering knuckles, supports, steering arms, backing plates and brakes as an assembly. But I got to wondering -
Is it possible to bolt EJ-HD front brakes directly onto FE-FC steering knuckles without changing to EJ-HD steering knuckles and supports? There is no firm consensus. So I decided to find out, by doing.
Here is an HD kingpin front brake assembly happily bolted up to an FC steering knuckle.
From this angle it looks no different from the original HD steering knuckle and support. From the back side, though -
A couple of things of note -
The upper holes in the FC steering knuckle support are threaded, so I had to change to short 3/8" UNF bolts.
The steering knuckle forging has the number 3415/6, which identifies it as later FE and FC (7413415/6).
And here is a photo of an FE-EK steering arm (left and bottom) bolted up to an EJ-HD steering arm (right and top), showing that the bolt hole spacing is the same between both types of steering arm:
Conclusion: Yes, you can bolt EJ-HD front brakes onto (late) FE and FC steering knuckles. You need to change the top two backing plate to steering knuckle attaching bolts to short 3/8" UNF bolts to suit the threaded holes in the FE-FC steering knuckle. You also need to use the EJ-HD steering arms. And if you are using HD kingpin front brakes (probably rocking-horse-poo rare these days), you will need to use HD or HR wheels.
Rob
