Model A - Rear Brake Rod

 The rear brake rod is a much simpler affair than the front - it has a clevis at the rear end and this just needs a new pin, which is easy to make on the mini-lathe using a tailstock V-block:

The brake rod is just a bit of 1/4 round bar, threaded 1/4 CEI for the adjuster. The clevis is there, though very worn and we can find a spring from stock. The adjusting knob is missing, so we will turn that from a bit of 303 round bar, 1 OD:

It's reduced to 1/2" at the rear end, and the front appears to be domed but other than that is is similar to the front one. Same straight knurl:

Dome is made after parting off, with a combination of turning and a bit of filing:

We can mill a shallow groove in the rear to accommodate the clevis using an end mill.

Job done, though I think that trunnion will need replacing.

Model A - front brake rod

 The Model A came with its original front brake rod, but none of the fittings. It's an odd design - the rod is 3/16" (0.1875") but, to prevent rotation in the brake arm, it's flattened at the end. This makes it larger - it's actually threaded 1 BA, on a major diameter of 0.209".

Of course, cleaning up the thread is a bit of a challenge with the flat since many dies will not bite having three sets of flutes, or very narrow flutes, as the thin rod disappears into the gaps. 

Here's my stock 1BA die:

See the narrow flutes? This next picture is another I bought:

The flutes are much wider on this one, and I managed to recover the thread and get my newly-turned adjuster knob to fit. It's made from 303 stainless steel on the lathe, milled for detent on a 1 BA mandrel in the toolpost:

The outside is cut with a deep straight knurl, slightly chamfered:

The next lathe job is the spring housing, copied from the one on the W/NG. It's a bit of 1/2" 303 round bar with a 1/4" CEI thread in one end, bored 9.5 mm for clearance on the 3/8" brake rod end:

'Puzzled' of Norwich writes on the subject of Brake Rods...

Out here in the hinterlands of East Anglia, the winter has been hard & long & devoid of much motorcycling weather, so we have had to content ourselves with small jobs we can do inside, or snatch brief interludes of inner (shed) calm amidst the fun & excitement of family life.

Brian Challinor mailed with a question about the straightness of my brake rod, which had to wait for such an interlude. My brake rod is as straight as the day it was drawn through the die, since it is brand new and has never been fitted.

However, since that interlude came today, I have had it fitted to the bike. Here are several shots showing it in place:

As you see, it doesn't fit - due to the aforementioned 'straightness'

Here's a shot from a 1989 copy of 'The Classic Motorcycle' of a supposedly 1952 Square Four - I say 'supposedly' because there are a few elements that are more 1950 than 1952. Here's the brake rod:

Careful study will show you that it is bent as the proverbial 9 bob note.

Here's another one, a 1951 bike sold at Andy Tiernan's a few years ago:

Again, bent. The case rests m'lud.

So, another day. another interlude... I have taken that most useful of tools, the wire coat hanger, and bent it to form a dummy brake rod, for the purpose of determining the routing the real thing should take and the bends that would be necessary to accommodate that routing. Having satisfied myself, I bent the real thing. Here it is:

Side view, see how long it is, and the poor (low) position of the brake lever?

Here is a top view, which gives an idea of the two bends:

And here is a view of the brake rod and it's proximity to the brake plate and Anstey stirrup:

Looks like the brake arm might be the wrong way around, and the rod needs to be shorter. I'll leave that until I have relined the shoes and positioned the pedal properly - once it's cut shorter, it can't be lengthened again!

Here's a view from Brenton Roy's original '51 Square, suggesting that my installation is along the right lines:

Proving yet again that the AOMCC forum is a wonderful resource for us! I'm thinking that my brake arm is a little more bent than Brenton's: