Morris Minor Owners Club

If backing off the detent bolt has caused the reverse plunger to not work (ie. there's no resistance to pushing the stick over to the right), you're running a risk of accidentally selecting reverse at speed and smashing the box. Even if you're sure you'll never do it yourself, do you ever let anyone else drive the vehicle?

In practice it feels no different to any other Minor box, although as said earlier the lever does not tend to spring back when let go from the right, but that could be tightness of anti rattle plunger etc. I take your point about others driving, although unlikely.
When its on the road I will see what happens, if any doubt I will change it then, thanks for all your help. Strangely I've just finished building another gearbox and that is the same!

I have a slight problem in that department too. If I selact reverse and then drive forward, I can push the lever into reverse with no resistance. Obviously not pulling lever down to actually engage reverse. I then push lever back and the resistance is then back to normal. Seems as if this plunger is sticking occasionally.

In your case it does sound like a sticking plunger, although it is spring loaded, unlikely but maybe a broken spring.
As an update, I have finally cracked the reverse selection problem on both gearboxes, if I select reverse and THEN screw the spring loaded bolt in with normal thin washer, now return to neutral, from then on I can get reverse with the normal tap to the right then down! I can't tell why this is yet, but at this moment in time I don't care!

Cool, glad you resolved it!

Yes all ok, thanks for your help.