My 95 XJS makes a double-click every thirty seconds (when the ignition is on) and whenever my foot touches the brake pedal. One mechanic suggested that this means the nitrogen bulb is empty and must be replaced. I learn to ignore the sound and the brakes work fine, but is there a danger inherent? I've seen the ABS Bulb (is it called an accumulator?) for around $400 and have located one from a wrecked '89. Thanks for anyone's advice.

 

I've moved your post from the General Tech Help to the XJS section where it will get greater visibility/response from techs and members with similar model

regards,
steve

 

Hello barmorehome,

If you do indeed have an early '95 then you have a Teves III system with the Nitrogen Ball (accumulator).
On pages 457-458 of "The Book", you can read all about testing the accumulator, buying a new one and installing it. Don't buy a new one from the dealership, and don't buy a used one. Chances are a used one from '89 will also have lost it's charge as well. And a new one from AC Delco on Amazon is about $110-$140. Part number 25528382.
When I bought my '94 in 2012, this was the first thing that I changed out. Fits and works great.
Bill

P.S. Regarding the danger. If the accumulator has lost it's charge, the pump will be running more often than it was designed to. It can overheat and cause brake failure.