I modified my bumpers yesterday.
I followed Doug's modification and realized that you do not have to remove the bumper shocks to do the job. It can be done on the car.
Remove the bumpers to expose the shocks and drill 2 holes in the exposed portion of the shocks. I then used compressed air to blow out the white stuff.
I then drilled and threaded a third hole through the larger portion of the shock to lock it in place. See pics

 

Finally got around to this myself. Drilling in place led to only a tiny amount of the filling coming out so I pulled the buffers/shocks whatever they call them to see what's what.

They can be dismantled. There's a jam nut on the end and the outer sleeve of the shock is threaded. I cleaned up the threads (M10x1.0) so that I could unscrew it - trying with rusty threads just led to the rod spinning inside the other section. Once removed you can see a cap that can be unscrewed and voila - all kinds of gunk comes out. In mine there was a combination of hardened gel blobs and white powder. There's no way those blobs were coming out of drilled holes. I suspect that the powder is what happens to the gel over time. I wonder whether the absorbers even work after this kind of degradation.

Anyhow - I took pictures along the way.




Jam nut



Cleaning the threads



Remove the cap



And we're in!



Gunk

 

nice work, im trying to source a series 1/2 front bumper here but its hard to find. i plan on having 2 front ends that i can interchange, the custom one i have now, and a stock ish one that still has a crashbar

 

Does this mod just allow the main rubber bump bar to retract into the bumper, as if there was an impact?

 

Sunchip.
I have a yard full of XJ's in St Catharines. I think we have communicated before.

Rob 905-937-0264

 

It basically disables the 5mph bumper functionality. What you gain in aesthetics (the look of the European bumpers) you will lose in the bumper's ability to absorb the impact without damage to the car - so definitely something to bear in mind.