So, here's the finished job to show what we are talking about. Springer comes with an axle. At an extra cost, the caliper comes with mount and spacers, none of which I was able to use...
Hope you can understand this diagram. It's called a sectionalised drawing... imagine we have magically cut the whole assembly in half and can see all the parts. None of the spacers supplied filled the available gaps let alone centering the wheel.
On top of that, the caliper mount has to be free to rock on the axle. This is accomplished by the bronze bushes I have made touching each other with a gap of about 1 mm clearance. The brass bushes supplied pulled everything up tight so had to be discarded.
One spacer is needed on the left (speedo drive) side.
Two spacers on the right (brake side). The inner spacer locates the caliper centrally over the rotor...
The following photo is an attempt to show the damage to the inside of the caliper mount axle hole. Though supposedly new, the hole has been coarsely filed and was very rough inside as well no longer being round. The two brass bushes that it mounts on were not only very loose (ie about 2mm of play) and would wear rapidly on the rough hole, but also as mentioned would have jammed the caliper mounting bracket.
Simplest solution was to set it up on the rotary table on the mill and ream out the hole with a cutter. A spacer is made to the size of the hole to locate the caliper bracket and once clamped down, the spacer is removed to allow the cutter in to re do the hole. Missed taking a photo of the process, but the table is simply rotated and the cutter cleans the hole...
Final polish of hole with 200 wet and dry on a piece of 25mm tube...
Next, I made up a pair of bronze bushes for the caliper bracket. Note that one of them has a rim 1mm wider than the other. Tell you why soon...
Wheel is centred at the hubs (52mm each side)...
Left can now be measured for spacer. Although aluminium is quicker to machine, rest of the set up is chrome, so I use stainless...
left spacer installed. Now inner spacer can be measured for. Blue arrow shows the 4mm gap that needs to be filled. Rather than make a 4mm spacer and have two spacers I make up one spacer...
Inner spacer made and measuring for outer spacer...
Outer spacer made and axle pulled up tight. First time, the rotor touches the right of the caliper, so I swap the bronze bushes (remember they were different thicknesses) and it lines up nicely...
A couple of stainless button heads and a nice chrome acorn (not dome) nut and the job is done. Caliper moves freely and the wheel is centred. Should not have been necessary, but as was the common statement in the seventies, "Bolt-on ain't bolt on"
Right side...
Left side...
