Thats a class tool
How did you hold the centre rod to stop it from turning ?
I need to replace the damper on my G/S.
Ah, now thats the trick.
First, press out the rubber/steel bush because of what you have to do later on.
If you don't have a press, you can improvise with a 'large' bench vice. Place a 1/2 " drive socket just smaller than the eye that its located in, on one side and a large socket on the other side. Place this into the vice. You might need a 2nd pair of hands to help do this. Wind up the vice and literally push the rubber/metal bush from the eye into the larger socket.
I looked at car McPherson spring compressers - too big.
Specific motorcycle spring compresser (eg Sealy) approx £40.
Used 8 pieces of 2" angle and 4 pieces of M10 studding - Cost £0 = Result.
That is now in the 'specials' box, along with others made for other jobs. Its HD, so will last a long time.
If you compress the spring enough to leave the alloy end cap free from the spring, look carefully at the shaft immediately under the cap. SOME shafts have 2 flats to get a 10mm o/e spanner on. If not you will have to grip the shaft with mole grips (eugh!). The shaft is hard chrome plated so will withstand the grips. However if you do mark the shaft right at the end, don't worry, that part will never go past the damper seals as the bump stop rubber will prevent it.
Heat up the alloy end cap with a blow torch, gently, and put a steel bar into the eye of the cap and turn. Only heat it up enough to enable it to turn free. Conventional R/H thread. By heating, you will break down the threadlock used to secure the cap and shaft together.
The cap will drop off, and remember 'Its Hot'. The spring is now free to be removed. The chromed adjustment collar at the bottom of the shock can now be removed. You might need WD40 or similar and a little persusion.
The shaft on this shock did not have spanner flats so I carefully ground 2 x 1 mm flats opposite each other with the Dremel. Shaft is dia 12mm so with 2 x 1mm flats this will suit a 10mm spanner.