Model A - rear brake pedal

 The rear brake pedal shaft is one of those areas where you see the horrors perpetuated on old motorcycles through years of neglect and changes of ownership with varying levels of skill. Having removed this one to rebuild the footrests and replace the brake pedal spring we realise that it is in fact a bit mangled.

To start with, we can see that the thread has been cut to a BSW form - Ariel would not have used BSW here, the thread would originally have been CEI. We will build it up with weld and cut a new thread to the right size.

That pin across the right hand end as we look at it forms both the stop and the fixing point for the end of the spring. Part of it, the fixing point for the spring, has broken off. It proves impossible to knock out though it is listed in the parts book as a separate component, so we drill it out.

Here it is, illustrated in the 1930 parts book:

The other curiosity which I didn't understand initially is how the shaft is lubricated. There was no obvious grease nipple but under all the gunge a hole appears half way along the shaft, which is clearly to let grease into the central reduced area - and an ex-nipple on the end which has had some attention from a hammer.

I've said many times that the AOMCC is a wonderful club to be associated with and a few questions posted on the Facebook page yielded this drawing from 1925 and signed by Val Page himself. The drawing clearly shows the same formed nipple on the end of the shaft that the later Ariels used until the end of four-stroke production in 1958.

The difference between this and the later bikes is that whilst the later bikes use a nut to retain the brake pedal on a parallel fixed shaft, this application uses a nut on a taper to retain the pedal on a rotating shaft. Therefore when you want to remove the pedal for adjustment, you have to undo the nut and knock the end of the shaft to free the taper. Guess what happens? The nipple gets flattened...

To start with we're making a new pin on the lathe. I didn't intend to use a piece of stainless, but at the time I couldn't find a quarter inch piece of mild steel round bar - but no one will ever see this, so it doesn't matter if it's the wrong colour.

I've cut a semi-circular channel in the end of the short bar to locate the brake pedal spring. It's a simple matter to chamfer both ends and press it into the pedal shaft.

This is how it looks.

This is apparently the correct spring - I got it from AOMCC Black Ariel spares some while ago and I'm assured it is the right one, though it looks very stretched when it's in position.

See what I mean?

The next step is to build up the mangled thread and nipple. This is none too tidy but hopefully there will be enough material to turn it to 7/16" without firing up the TIG set again.

The first pass at turning to size shows, as it often does, that more building up is required:

That done, we can start forming the shapes according to the drawing with a radius tool to form the curve and shape the grease nipple:

I seem to have missed out a step here - I've forgotten to photograph the drilling out of the grease hole, which is 5/32" per the drawing. The next step is to cut the 7/16" CEI thread. 

Here it is on the bike with the brake pedal attached:

We will need to be very careful when moving the pedal - using a socket or something over the nut to avoid damaging the nipple!