if it is leaking (green) hydraulic fluid, you have to fix the leak issue, since the brakes are tied into the hydraulic system on that year's model.
There is a device that works with your brakes to help the brakes,it is a servo pump that has gone out on your car. Mine went out too but I am strong so I just use the brakes without the servo pump.
5 inch speakers in the 96 Jag XJ6
Alpine
Dexron III
R134a freon......
the battery for your jag is in the trunk right side
Its in the fuel rail at the end of the head after the last Injector.
55,000
most likely the CRANK POSITION SENSOR
on the left side of the steering column... under the steering wheel.
Buy a manual and figure it out an if you can't call a jag machanic to do it for you.
BIUSxx