My car felt as if it were running on the front bump-stops on the way home tonight, when I crossed 2" high kerbs etc.
this is the front driver's wheel- it was fine this morning
I can't see a broken coil, but summut aint right..

I am due for front suspension bush replacement this week anyway, so I guess it just got a little dearer.

the problem was a binding shock absorber
the solution is a new pair of front KYBs going on today

I thought there was a 4-5 cm difference in front height when I took the photo above
A week later the mechanic said there was no difference, he replaced all front bushes (ball joints were fine, springs were fine).
Then after a short road test he phoned back- the front shock was stuck in a compressed position, so diagnosis made.
I have a 250 mile road trip Saturday, so looking forward to good front suspension again!

the new KYBs are not impressing me - the wafting Daimler ride has been replaced with a harsh front, but supple rear still there
the mechanic has the old shocks - "Bilstein Jaguar Germany" stamped on'em
They are now at a Bilstein expert who is rebuilding them
It was stuck in a compressed position because a plastic part which is an 'anti-sag' component breaks up with age and tiny fragments block the oil flow passages, jamming the shock

So my rebuilt "Bilstein Jaguar Made in Germany" original shocks were refitted today

Pure revelation and comfort.
The KYBs were horrible.
Now Old Blue wafts beautifully again.
The originals were knackered, and one shock had a bent rod, replaced.
I would recommend to any of you - find a Bilstein whizz and have them rebuilt not replaced. Same price for both options, in NZ at least.
I also had new orange sponge genuine Jag bushes fitted, no doubt a significant part of the solution.

Glad you got sorted. I've never heard of that happening before.

thanks Steve
I am happy with it now
I will keep an eye on those orange top bushes, and have them replaced when necessary - I think they are a big part of the ride comfort. My mechanic told me they were used for many years on Series III/XJ40/X300 and for all I know longer.. Presumably Coventry Head Office spent a lot of time getting the ride right. People grizzle about these bushes not lasting long - they are a sacrificial element, so we've all gotta just suck it up, and replace them as needed.

I'd like to re-name this thread "Front shock rebuild" as it would be more accurate...

Done!

thanks Steve

Now, 24 hrs later, I feel like Goldilocks.
The KYBs were too hard (but great stability at speeds over 100km/h) whereas the rebuilt Bilsteins are perfect around town but a bit light at speed and allow a bit of front wheel skitter on bumps up around 130km/h.
So now I wonder if they are too soft! Hard to please some people..

I searched both the Bilstein and Koni sites.
Koni have one part number for all of the X300 range, whereas Bilstein have two different front shocks - one for 3.2 and 4.0, the other for XJR & V12. Expensive, though, at about 270 Euros plus sales taxes per shock..

(.. I like my porridge not too hot, not too cold)

those KYB dont last either. mine didnt make it to 6 month