Just finished up replacing the front spring mounts, and adding spacers to compensate for spring sag on my '99 XK8. Very feasible project for most home mechanics. No lift needed, but I had to buy a spring compressor and little shock nut toolkit. I cut spacers to fit on top of the shock mounts, drilling three holes in each for the mounting studs, pretty much like pistnbroke describes several posts back. I used plastic cutting-board material from the grocery store, about 0.33" or 8+ mm thick. That is about the thickest that will work with the stock studs. I figure that this and the extra thickness of the new mounts gave me about 5/8" (16mm) more total strut height, which translated to about 1 1/4" increase in ride height, (just what I needed). Please note that these numbers are VERY approximate! My new mounts are the much maligned URO yellow foam ones, so we'll see how they hold up. I'm ld enough that maybe I'll never have to change them again!

Another possibility would be to add to the stack of spacing washers at the bottom of the spring, about halfway down the body of the shock. In any case, adding spacers is a LOT cheaper than replacing springs.

 

I hope you're URO mounts hold up because that is what I will likely have to use.

 

Adding spacers at the bottom would in effect increase the length of the spring and would at least maintain the correct travel of the damper. Adding at the top, above mount will not change the spring length and while it may lift the body you will still be stuck with a decrease in your available travel.
I don't know your age Bob, but there is absolutely no doubt you will outlast a URO mount.

 

You can get 12mm of board on top of the mounts because the studs have 13mm of excess thread. Doing it this way you dont actually need to get the spring out witch I think needs removal of the top wishbone and shock ..let me know if that is wrong.If my top mounts are shot (they look OK) I shall seal them up and fill with liquid polyurethane.1

Here is the spacer . Use a jigsaw if you dont have a lathe

160mm dia 90mm dia hole..dont you just love artificial grass.

 

That's more or less what my "cast in place" involves but the shock mount washer needs to be properly located within the mount bell. If your mount foam is stuffed and spring pressure is still present that washer will be held hard against the bottom of the bell, it won't help to fill the space above with poly.

 

I think you miss read what I said...If you just want a spacer above the top mount then you dont need to remove the spring from the car though you do need to hold it with spring compressors.
If my top mounts are stuffed I would dismantle them / have the shock mount washer in correct place before filling. Sealing and putting removable mandrills in place. May even vacuum bag it to stop any leakage. As I am not running a production line like you I can be a bit crude for a one off.
I have edited the original text to make it clearer.

 

All clear now.

 

The lifespan of those URO upper shock mounts can often be measured in months, not years....