G'day Mystyler,
Taking your questions in order, and referencing the Exploded Diagram on p.122 of your #424 Manual;
1. Remove the top section of the handle, by undoing nut #81, and withdrawing the Locking Bar #82.
Then remove the Latches, #23. Note how the spring #24 is fitted, and preferably take a pic before pulling it apart. IIRC, the Latches are retained by an e-clip on the end of the spindle. Or it may be necessary to remove nut #28, and remove the Latch and its Bush as an assembly.
The two lower handle halves can now be removed; again IIRC, these may also have an e-clip retainer, on the end of the pivot pin.
2. No. It has an e-clip retainer, #76, which has to be removed first. The position of the e-clip groove can be seen in the pic of the rod, #10. It can then be drifted out - I'd start off with a pin punch and medium-weight hammer.
3. Correct - the roll pin has to be drifted into the handle; ref. Diagram on p. 130. It will then be necessary to get the roll pin out completely, from the inside of the handle - a pair of needle-nose Vise-Grip pliers is very useful for such tasks [also great for removing e-clips]. It may be necessary to remove the Pivot Pin to accomplish this.
4. Sometimes! These 'push nuts' are really intended as 'single use'. My most successful technique with these, is to grip the outer edge in a pair of Multi-Grip or Vise-Grip pliers, and 'rock' the nut while pulling upwards.
5. Ask Bruce at the ODK Shop - he will know.
