This question is for a LHD car, but RHD may have the same parts.
I took this apart quite a few years ago, and though I don’t think I have lost any parts, something doesn’t look right.
I have a flat washer that is larger than the sleeve, but smaller than the roller bearing OD, so the pedal arm is able to slide over it.
If I assemble it with the washer against the bearing, as I think it should be, there will be a gap between the pedal arm and the adjacent brackets where grease can splurt out and dirt can get in.
- Is this the right washer? No washer is mentioned in the parts catalogue, nor in the XK120 PC which is mostly similar parts.
- Should there be some kind of felt washer or o-ring to keep grease from splurting out and dirt getting in? There are o-rings on the clutch pedal arm for this purpose, although it does not have a grease fitting.
- Should there be a lock washer under the nut? Plate L7 in the manual seems to show a Philidas nut. I see the PC calls for a 1/4" Philidas nut but that can’t be right, probably should be C.3320/4 instead of /1. The XK120 PC calls for a regular 7/16-20 ANF nut, which is what I have.
Nut and washer in place
Pedal arm assembly
Here is the chassis bracket where it attaches under the torsion bar.
Hi Rob, checked my car tonight. My Mark V has a large ball of grease in the region where you are interested. The grease ball has worked well for at least the 15 years of my ownership. May I suggest installing a large ball of grease will be much easier for you? Probably on Saturday I will be under the car, clean the grease ball out some, and see what can be determined without disassembly.
Solved it. The washer does not belong. The problem was the sleeve had a divot inside, was not sliding fully onto the shoulder bolt which also had a bit of distress. Polished them both up and now its fine.
I will install the grease ball as Roger suggests. 
Hi Rob, grease ball was cleaned off my brake linkage for visual inspection without disassembly. Assembly is similar view to your photo above. Only washer visible to my eye is one under the nut (red on your photo). The nut on my assembly does not show red paint remnants, but I did not check for AN or BS spec, some of the AN nuts on my car don’t have red paint (due to replacement or maybe were not painted red initially).
Thanks, Roger.
In case this comes up again with anyone else, I found C.3361 LHD brake pedal shaft is a .499" dia shoulder bolt, C.3224 is a .505" ID steel sleeve 1.510" long, and C.3223 sleeve bearing is 1.499" long. The design is that the sleeve contacts the brackets while the sleeve bearing has .011" free play. It is similar on RHD except for the welded stud on the chassis instead of the shoulder bolt.
I am finding nearly all threaded parts on the chassis are ANF thread and many have a thin coat of red paint on them, so I have been restoring them in red.
One exception is the GB.1273 rear shoe adjuster bolts, also used on Mark IV; they are 3/8-20 BSF, so I restored them in black.
