I'm starting a new thread on this, since my original post is buried at the bottom of the thread on V-12 Proper Firing Order. Since we diverged onto the issue of power steering giving too much assist in the Ser. III cars, and I posted a simple fix for the problem, I thought a new thread was appropriate. So here is what I wrote:
There is an easy and inexpensive fix for the power steering "over-assist" problem. There is a valve located in the back of the power steering pump, with a hose coming out of it. Behind that valve, there is a rather heavy gauge spring. You simply unscrew the valve (with a large pan under it because a LOT of power steering fluid is going to pour out), remove the spring (long tweezers will help here), and replace it with a lighter gauge spring of roughly equal length and diameter. Some shops cut the original spring down, but it is easy and cheap to find a lighter spring of about the same size. Then you always have the original to put back in if you want.
Pascal Gadamer installed a unit in his car that allows for variable adjustment, but as he noted, once he had it set, he never changes it. Pascal's adjustable fix cost several hundred dollars. The "spring exchange" fix costs less than $5.00, for the spring and a bottle of power steering fluid. The whole job takes about 10 to 15 minutes, including removing the left front tire and putting it back, and requires no more skill than being able to turn a wrench and wipe power steering fluid off your hands.
Steve Weinstein, JTC-NJ
'72 E-type 2+2
'89 XJS Coupe