Showing posts with label brake pedal. Show all posts
Showing posts with label brake pedal. Show all posts

Saturday, 17 January 2026

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!

Here's an overall view. That pedal is very high!



Wednesday, 31 December 2025

Model A - sorting out the footrests

 The footrests on the A are a bit of a mess. One is thoroughly non-original and is probably homemade, the other has been shortened radically, to the extent that it is useless. Also in this region - the spacer between the engine plates (that prevents tightening the footrests from squashing the engine plates) is missing, the brake lever return spring is missing and the brake lever spindle has been recut with a BSW thread - it has obviously been stripped at some point.

Ariel footrests don't change much and I have a new set from club spares:

The rod is bent, but worse the threads are worn on one end and recut to 7/16" BSW. I've got a large piece of stainless steel to make a new one. In that package of spares was a brake lever return spring.

The two footrest supports were also bent but a few minutes with the MAPP torch sorted that out:

Next, we need a bit of time on the lathe to make the spacer that goes between the engine plates. We'll use the manky foot rest to provide the material: 


With the power feed on, it doesn't take long to clean up this bit of bar:


It's turned down just enough to fit inside the brake lever spring, bored 11.5 mm to clear 7/16", and parted off at 2" long. It's lightly chamfered at both ends, inside and out:

So that is that for the moment. The bar is a little bit long and one of the nuts is very loose and needs replacing, but we will sort that out when the rear brake pedal shaft is finished and it all comes apart again.

Sunday, 10 December 2023

FH - bottom end complete

A little bit later than expected I am back in the workshop. My generator decided to burn out it's alternator winding, and took the battery charger with it which meant buying a new generator, building a trolley for it (it doesn't fit where the old one was) and building a trolley for the welders - because their spot is now taken up by the generator...

Having got most of that out of the way, I can strip the cases again to fit the replacement connector rod nuts, BSA part number 37-1691. These are genuine new old stock from Vale-Onslow. Looking at the picture below, from left to right we have the modified Draganfly nut, an unmodified nut, and on the right the new lower profile nut:


This, by the way, is the mark left by the Draganfly nuts before I modified them:


Here are the Draganfly big end bolt washers. These are laser cut stainless and whilst some suggested they were rather small, they are much the same size as the bearing surface of the nut so I am leaving them in place.


Stupidly, I forgot to picture the new nuts in place on the big end caps. Mrs H phoned to see where I had got to (I'll just be 10 minutes dear!), and that's always a distraction. Suffice to say that they were torqued up to 22 lbf. ft in accordance with the BSA data sheet and I oiled up the various bearings before closing the cases. I made sure to remove all traces of Threebond and was very sparing with it when reassembling.

The case bolts are all stainless, from Acme as usual and they fit beautifully. I made this chart from the diagram in the Draganfly catalogue to show me where the different bolts go:


Lovely and easy putting them in; I used my frame spreader to make it a bit easier.


Now that the bottom end is in, we've got a number of workfaces to tackle:
  • the barrel and pistons
  • the primary case
  • the timing gear
We can look at any of these really but before we do there are some components around the engine that will become less accessible as we progress. The first of these is the engine breather shown here in the form in which it arrived:


This isn't how Ariel designed it. It's supposed to bend around and appear behind the FERC, above the gearbox sprocket somewhere.

Another item is the magneto. It's fitted here temporarily with the long bottom nut, which is on the job list for zinc plating. With the primary case loosely bolted in place you can see that it's quite restricted in there:


Something that surprised me, and thanks to Daniel Rix on the FH Facebook page for this, is that you cannot get the brake bell crank on with the primary case in place. That's a pain, because I want to get on with the mechanical build and I hadn't planned on doing any plating just yet... and the bell crank needs plating.

The other thing I must remember is to fit the oil lines before I fit the primary cases! Access will be a trifle difficult if I forget, so let's not get ahead of ourselves and we will get on with sorting out some of the details.

Sunday, 19 March 2017

Brake Pedal

For some time I have seen the brake pedal above the footrest like this:


It's very difficult to get your foot onto it in that position and quite unnatural. It's caused by the fact that the brake pedal stop is missing, having been replaced by a plain bolt. You can see where the stop used to be, witnessed by the dent in the brake lever:


Its a simple matter to make a new one, out of a 5/16" bolt and a short length of 3/8" round bar, welded together:


This is a genuine Ariel one:


Here it is in place:


This is how the pedal sits now: