Pedal Box

The pedal box on cars prior to the boosted dual circuit system: AHH6065 for Mk1 cars, AHH8421 for single-circuit Mk2 cars with an over-size hole for the brake master and no lower reinforcing to accept the unboosted dual circuit master, although they were fitted to all cars until they gained the boosted dual circuit system. These also have the clutch master canted over a bit to clear the dual-circuit master reservoir cap, but that may be in the construction of the master itself and not the position of the holes in the box. This picture from Dave O'Neill - Mk1 on the left, Mk2 on the right:

Item 15 'bush, pedal' AAA4129 is for both pedals (was NLA in October 2016, shown as available from several suppliers in January 2017). Item 6 'bearing tube' is the pivot bush AHH7201, again the same for both pedals. 11 is the two spacer washers PWZ206, and 10 the distance tube AHH6063 that fits between the two spacer washers. The pivot bolt bushes are slightly wider than the pedals, so that when the bolt and nut are tightened the two pivot bolt bushes, spacer washers and distance tube are clamped up between the sides of the pedal box, which leaves the pedals free to rotate on the pivot bolt bushes with minimal sideways movement and 'wobble': (Moss Europe)

October 20918: However there is an oddity in the screws that attach the pedal box to the heater shelf. The Parts Catalogue doesn't explicitly identify these, but under item 8 - 'AHH 8421 (for example), Box - master cylinder there are six HZS405 (1/4" x 5/8" UNF, 7/16" head, item 37 below), one HZS407 (1.4" x 7/8" UNF), seven PWZ104 (1/4" plain washers) and seven LWZ204 (1/4" spring washers). You could be forgiven for thinking that the six HZS405 would be for the pedal box, but you are wrong. The middle one on the brake pedal side is actually 5/16" x 5/8" UNF (1/2" head, item 38 below), which is listed next in the Parts Catalogue i.e. HZS505 together with 5/16" plain and spring washers. I discovered this on the roadster when looking underneath the shelf for an attachment point for a mechanical brake light switch, and noticed this welded nut is noticeably larger than the other five. Wondering if it was a one-off I checked the V8 and it is the same. The only thing I can think of is that they opted for a bigger screw beside the brake pedal, as there is going to be a lot more force applied to that pedal than the clutch pedal. Still odd they didn't do it both sides though. Along the way I discovered that one was not fitted to the V8, I must have tried to use a 1/4" when putting things back after the repaint in 2017, discovered it wouldn't fit, and somehow it got left. As I need to fit a longer one to the roadster for said brake light switch bracket I transferred that one over. Initially I thought I would have to remove the pedal cover, but there is just enough room between that and the wing flange to get a 3/8" drive socket and extension bar in.

Incidentally the upper pedal box securing bolts (arrowed in red above and below) are a pig to remove as the bolts go through from the cabin side, and you have to go up behind the dash behind all the wiring to get at them. The inboard one is even worse as it has the steering column supports (later column as on Vee at least) below it as well. Removing it for Vee's (75 V8) repaint I got to the outboard one with two 3/8" drive wobble extensions, but the inboard could only be accessed with a ratchet-ring spanner. Initially I only had three very fine clicks of movement, which would have taken forever (even when loose I couldn't get my slim fingers to it) but by removing the relays and voltage stabiliser, and the indicator flasher and its clip, I got about 15 degrees of swing. Still took patience though.

July 2022: Steve Long has a 74 UK roadster and writes:

"To get to the left one simply pull the wiring loom towards the steering wheel and use a 1/4" drive 7/16" socket - I got about 100 degrees movement. The right hand screw is behind the windscreen wiper motor; undo the two 7/16" screws holding the wiper motor in place and it will hang on its track leaving plenty of clearance to get to the hidden screw. Undoing the pipes from the back of the master cylinders is a whole different story!" I have changed master cylinders on both cars and can concur with Steve's final sentence, but on Vee I was stripping the engine-bay so removed the pedal box complete with cylinders and pipes, and refitted pre-assembled, so was able to avoid that. The harness arrangement is completely different for 4-cylinder of that era and V8, I'm sure I would have done everything I could think of to get better access to that bolt.

The pedal arrangement labelled with the item numbers in the above drawing, only the pedal (15) and pivot (6) bushes are hidden. With this arrangement everything except the pedal and its bush (for obvious reasons) should be clamped up tight:

When gripping the distance tube 10 you should NOT be able to rotate it ...

... nor the spacer washers 11. If you can it's not clamped up as it should be. If clamping it prevents the pedals moving then either the pedal bush (15) is too wide or the pivot bush (6) is too narrow. If 10 and 11 are clamped up tight but the pedal still wobbles excessively then either or both of the pedal or pivot bushes are worn where they contact each other.

The boosted dual-circuit pedal box: Item 13 'Bush, pedal' BHH1101 for both pedals, not available as of January 2017. Item 12 'Distance Tube' BHH1099 is the pivot bush and item and 11 'spacer' BHH1098 for the clutch pedal, neither are available. However the drawings are not to scale as will be seen in the photos below. The pivot bush is much wider than the pedal bush, and the spacer is short and fat and fits over the pivot bush with the pedal. Item 6 'Distance tube' BHH1097 is the pivot bush for the brake pedal and is available. Note that as the pedal bushes are the same item, two of the shorter brake pivot bushes could be used for the clutch pedal bush (one cut down to give the correct overall length). Items 5 and 7 are conventional washers and used under the bolt head and nut i.e. their thickness is not critical, unlike the spacer washers used in the earlier assembly: (Moss Europe)

Showing the clutch pedal (at the top, brake pedal below) with spacer. What appears to be penny-washers under the pedal and above the spacer are reflections. The arrow indicates where the hole for the brake light switch must be on this pedal box, behind the brake pedal, which moves forwards (to the left in this image) and away from the switch as the pedal is operated.

Clutch pedal with the distance tube (pivot bolt bush) flush with the pedal on the left, protruding on the right. The spacer sits on the distance tube with the pedal. The bolt head has a spring-washer. These original bolts do have a plain section below the head, which current replacements may not have, and the distance tube is initially a sloppy fit on the threads. However the distance tube is slightly wider than the pedal plus the spacer, so once the bolt is tightened the distance tube is clamped between the sides of the box, so the clearance between it and the pivot bolt threads is irrelevant.

The nut (arrowed) is welded to the box. Tightening the bolt clamps the distance tube (pivot bolt bush) into the box leaving the pedal and this spacer (note) free to rotate but with minimal sideways movement and 'wobble'.

The brake pedal pivot is even simpler. The distance tube is fractionally wider than the pedal and its bush, and is clamped into the box by the bolt and nut, leaving the pedal free to pivot with minimal sideways movement and 'wobble'. There should be a penny-washer under the bolt head as well as under the stiff-nut.

This view shows that the lower clutch master cylinder nut (arrowed) is welded to the inside of the frame, and therefore that the bolt goes in from the back of the master: (Crispin Allen)