Xk8 spongy brakes - 1997 Jaguar XK8

Your brake master cylinder could be low,if it goes too low,then air will get in and become spongy.

Spongy brakes are caused by air in the hydraulic lines, or old/weakened brake hoses. They may also feel sponger if the brake pads/shoes are excessively worn.

It's probably the brake switch on the brake pedal this controls both.

So long as the brake booster is working, test it by turning on the engine, press the brake pedal all the way down, then shut off engine keeping your foot on the brake pedal, if the pedal comes up slightly pushing against your foot then the booster IS working.

Did you BLEED the brakes??????

I just went to Brake Masters this morning and had them replace the Master Cylinder since I was experiencing the pedal very spongy and going to the floor. When they replaced the Master Cylinder and they gave me back the car, the brakes were still spongy and going to the floor. I addressed this to them and they took another look at it, but when I took it for a second time, the brakes were extremely spongy. It was almost like they gave me back my car in worst condition to when I brought it in. Can you help?

Use a vacuum pump brake bleeder starting at the furthest point from the master cylinder. They cost abt $35. Be sure to keep master cylinder full... :)

how did you bled them back 2 front?

your brake switch, the one that activates rear brake lights has probably failed. Press brakes, have someone see if brake lights turn on, if no then it is a brake light switch problem.

spongy brake pedal indicates air in the system... have the brakes inspected for leaks as it leaks when you apply the brakes and sucks in air when you release them.

Robert