I also have a LR Discovery 2.
The top and bottom ball joints on those are a pain in the ass.
The first step is to remove the hub carrier that swivels on them then you need to push them out of the housings on the axle casting. The base of the ball joint is an interference fit into the housing casting.
It's the 2nd job that is a nightmare. Some garages won't touch them.
For this step I used a g clamp type tool specifically designed for the job. However, at this stage I knew I would distort the tool if I only relied on this.
So I did 2 things.
1. The day before I was to do the joints I took both front wheels off and had the vehicle on axle stands. I put a drip tray under each side of the axle then poured some old engine oil around the ball joint/axle casting interfaces, so the oil penetrated into the actual interfaces.
2. When I came to remove the ball joints I knew that I could easily damage the tool. A number of experienced mechanics had done exactly that. Many were blaming the tools being cheap. So I didn't rely solely on the tool.
On each balljoint I tightened the tool until I could just see it deflect, well within its elastic limit.
I then had a Hammer in each hand and brought them together 4 times onto the housing. The tool was then loose. The shock plus the pressure on the balljoint had started to move it forward out of the housing.
I then retightened the tool as before and repeated. A few times. The balljoint came out without a problem. No heat and no damaged tools.
Annoyingly, I lent the tool to a friend who, despite being told the above, returned it looking like a spent banana. He replaced it with new, so I can't complain.
What did this tell me?
1. My degree in engineering wasn't completely wasted
2. Regardless of the 'quality' of the tool, we can help ourselves by thinking our way through a job.
I too have broken a few joint splitters, but after my experience with this job I tend to approach things less with a fitters mindset and more with a human engineering mindset.
