Gear Stick Knob
My knobs come off in my hand!! (Gear Stick Knob)
Things have moved on. No longer is the Morgan Gear Knob just screwed on to the top of the gear stick! It’s become over complicated.
No wonder you can find gear knobs with witness marks from monkeys using monkey wrenches, mole grips or whatever comes to hand in an attempt to stop the gear knob coming off, rotating or just gone plain floppy.
Just in case you have a mullered gear knob and wish to change it to the more traditional plain top or old type screw on gear knob the Mazda gear stick thread is M10 x 1.25 mm. Therefore, most after market Japanese knobs will work. Except for some of the 4/4’s as their gear sticks come unthreaded.
The knob has 4 components (Photo 1) or 7 if you wish to be pedantic, they are as follows;
- Inner Boss with Plastic Insert
- Grub screws (3 No.)
- Threaded Collet
- Gear Knob
Tools required:
- Soft grip tool (or lots of rubber bands)
- 2.5mm Allen Key
The gear knob is held in rotational place with the threaded collet that locks onto the bottom of the gear knob (just like a lock nut would). The gear knob, threaded collet and the actual gearbox stick, pictured; show the scars of monkeys, tightened for fitment or undoing with incorrect tools or lack of mechanical knowledge.
This gear knob kept rotating, well to be more precise the hole gear knob assembly rotated on the gear stick, due to only one of the three grub screws being used and that grub screw had passed through the threaded boss and wedged between the boss and the plastic insert.
To allow for the removal of the gear knob you need to release the threaded collet from the bottom of the gear knob. This is best done with a soft grip tool, so not to damage the surface finish (Photo 2.)
With the threaded collet undone from the bottom of the gear knob you can now unthread the gear knob from the inner boss (Photo 3.)
The 3 grub screws around the inner boss are at the 12, 4 and 8 o’clock positions they push the plastic insert onto the gear stick, which in turn holds the gear knob in place when assembled (Photo 4.)
You can know see why many late Mogs have a floppy or rotating gear knob as the inner boss is loose, worst case your gear knob can even lift off in your hand. In (Photo 5 & 6.) you can see where the threaded boss has rotated on the gear stick and the grub screw gouged the thread.
Photo 5. Thread size is M10 x 1.25 mm 
Photo 6. when all the grub screws are loose you can lift of the inner boss
Now for the correct fitting of the gear knob simply reverse the procedure;
To fit the gear knob, ensure the threaded collet is placed on the stick first (photo 6.) then place the threaded boss on the stick, tightening all 3 grub screws so to centralise the gear knob when fitted.
Next, simply screw the gear knob to the correct orientation BUT not tight to the top of the inner boss ensure the decals are correct (Photo 7.) Then nip the threaded collet up finger tight first then (Photo 8.) using the soft grips again to lock the threaded collect against the gear knob.
Photo 7. When reinstalling the knob, Position the decals correctly then screw up the collet (finger tight) 
Photo 8. Nip up the Boss and Knob so that they lock
You now have a firm gear knob… perfect!
Note: If you are unable to unscrew the Gear knob from the Threaded Boss because it has been screwed on too tightly. Undo all the grub screws, so you can lift the knob and boss off in one unit. Then hold the boss in a vice thus enabling you to undo the knob (Note Photo).
Ciao Bambinos