Third gear splined locking ring.|
Wear on the reverse gear indicates the general state of the gearbox.|
Corrosion on the layshaft and bearings.|
Synchronising cup damage.|
Given a choice of two gearboxes you go for the one that looks as if it might be the best one to rebuild, so I
duly selected the one I thought was the best and proceeded to strip it down to check it over. On stripping it down, after the selector forks and shafts have been removed you take out the lay shaft so it lies in the bottom of the box to allow you to remove the main shaft by using a 'back hammer' to pull the shaft out. Of course this is after you have had great fun pushing the spring-loaded plunger down to twist the splined locking ring to enable you to slide the third gear constant mesh gears clear. It really is easy when you practice it when rebuilding the box, you will find that it is easy – once you know how!
As I suspected the bearings were all corroded, as were the shafts that ran in them, they would need grinding, chroming and regrinding to original. The bearings to be replaced in total and all of the inevitable knocks it
had acquired on the teeth of the crash box half of the gearbox (in case you might not be aware 1st and 2nd gears are of the crash or double de-clutch method of changing gear) had to be ground and polished
out. A big job for a little box, my first problem was that the M G Octagon Car Club Ltd., had all of the bearings
for the box they did not have the small needle roller one for the main shaft. I cannot get one anywhere, (if
anyone out there has one, please let me know, I cannot even give you the bearing reference as the only two firms that manufactured them no longer do so). Whilst waiting to be told this news I got on with attempting to recondition the box.
When I had priced up the bearings and the two shafts and the diameters they run in priced up, I thought
this was getting rather expensive so I held on wondering what to do whilst waiting for someone to come up with the needle roller bearing everyone was having trouble locating for me. In the meantime I had ground all the lumps off the "crash gears" and cleaned everything up ready for eventual rebuild.
Eventually I realised the bad news, no one had the needle roller bearing so I had to source another one! What, I thought, was the other bearing like in the other gearbox? I proceeded to strip it down too look, the adage came to me at about this stage, "Beauty is skin deep, ugly goes right to the bone"! The box that I assumed was the good one was not, I should have remembered, "Never assume, it makes an ass of you and me"! As you can guess the second box was in pristine condition, when I stripped it down it was perfect and I mean perfect! Bearings, shafts, gears, everything was perfect, so much so, I rebuilt it using all of the original
bearings, nothing required replacing! Putting the gearbox back together was an easy task, eventually, I now
know why there is a large taper on the lay shaft, the number of times it came out to reassemble the box was nobody's business. Also getting the 5 balls and 3 springs into the box for the selector detents is not the easiest task, but it all came good in the end.