Fitting New Ring Gear

[Robert Leigh]

I replaced the starter ring gear on my 1965 Rover P6 recently, never having done this before, followed the workshop instructions for removal and watched numerous videos on Youtube for the fitting, it is actually very simple to do, the important point is to make sure that the new ring gear is well heated, I popped mine in the oven for about 20 minutes on its highest setting, have the flywheel close to hand, some heat resisting gloves (the ring will be very hot), a drift and a mallet/hammer. Check carefully the orientation of the teeth and put this in the oven so that when it comes out it can simply be dropped onto the flywheel without having to flip it over.

Once dropped on, it will not need any force, a gentle tap all round to ensure it is fully seated, allow to cool and job done.

If the ring gear is not hot enough it will not expand fully and you might end-up getting this part-on only and you will need to then re-heat this carefully with blow lamp or hot air gun to expand the metal, either to remove and start again or to continue fitting, it needs care as the flywheel will also start to expand and you are working against yourself.

It is an easy job so long as the ring gear has expanded! Definitely look at Youtube videos!

I have not replaced a ring gear, but have used a similar technique to fit a home made bronze bush to a Riley torque tube steady bearing. The steady bearing 'cooked' in the oven and the new bush was in the freezer while I had lunch. It all fell into place and tightened perfectly as the temperatures stabilised. I suggest that the extra procedure of putting the inner member in the freezer can only make the whole job easier.

Robert Leigh