I planned from the outset with this project to fit a 4-pot front brake conversion to provide a bit more stopping power over the standard system, and as with anything of this nature there are multiple directions I could have gone in. I liked the idea of putting a system together using parts bin components from the period, which seems to have been a popular route for conversions of the past, but those parts are scarce now, so in the end I opted for another off-the-shelf conversion kit from Moss. Their 4 Pot Caliper Conversion Kit includes just about everything needed for a bolt-on conversion, including a pair of substantial vented discs, some gorgeous Wilwood calipers, and a set of EBC Greenstuff pads.
Most of the kit is pictured below, alongside an old 14″ steel wheel from a set that I was hoping to refurbish and use on the car to achieve a slightly different look from the usual Minilites you see all the time. Unfortunately after doing a trial fitting it was clear there was no way these wheels were ever going to fit over the new calipers (to be fair, it does say in the Moss details they need minimum 15″ diameter wheels, but there’s no harm in trying!).
Prior to fitting the brakes, I stripped down the original hubs and gave them a thorough clean, before rebuilding them with new Timken roller bearings all round.
With the now fully built front crossmember back on the car, I fitted the new brake discs and installed the rebuilt hubs – packing the bearings with grease and shimming them to the correct tolerances (this process is all very well explained in the Haynes manual and elsewhere).
One very useful learning for me at this stage: when I came to slide the new bearings over the newly refurbished stub axles, I found that they simply would not fit. They should be a very close, but freely moving fit, but the new bearings were interfering with the axle and would never have gone on without using force, so something was clearly wrong. At first I suspected I had bought incorrect bearings, but I checked and rechecked the part numbers and measurements and they were all correct. After some searching, I eventually found a thread on the MGOC forum suggesting that it was the refurbished stub axles that were the problem. During refurbishment the axles are sandblasted, which has the effect of creating a slight pitting on the surface of the shaft, which in turn increases the diameter very slightly, just enough to produce an interference fit with the bearings! The solution is to rub down the axle shafts evenly with a very fine emery paper to remove the pitting, until the bearings will eventually slide smoothly over them. Bit of an annoying head-scratcher for a while there, but easily resolved fortunately.
When I came to fit the Wilwood calipers I discovered they are too big to fit with the original brake backplates in place (which can be seen behind the disc in the picture above), so frustratingly the hubs and discs had to come off again to remove the backplates, and then all had to be refitted and shimmed up again – one day I’ll learn the lesson and test fit everything before committing properly, even when described as a simple bolt-on modification. Not sure how necessary the backplates were, I like to think that their absence can only help with heat dispersion.
Finally all done though, the picture below shows the finished result complete with the pads fitted.
