Hello there.

Something very strange just happens to me. I am driving for about 8 miles from cold start on A1A (next to the Atlantic Ocean) from Palm Beach to Delray Beach fortunately at about 30 MPH and needed to stop. I pressed on the brake pedal and it went to the floor. Shifted to first, left foot is pumping the brakes, left hand pulling on the hand brake, right hand on the wheel with rear tyres screaming on the asphalt! Feeling like Sebastian Vettel going the wrong way at the Brazilian Formula 1 Grand Prix. Every one is looking at this crazy no so young (any more) Jaguar driver thinking I am nuts, but I managed to stop the XJS. Pulled on the grass and check under the bonnet, all was looking good, so started the car and pressed on the brakes, ABS light is on Brake light is on and pumping the brake was giving me pressure, so I decided to drive another 8 miles at very slow speed, with all the following cars blowing their horns at me. The driving position was the same as earlier when trying to stop. I managed to reach a foreign car shop, explained my problem and got a ride home. Four hours later I went back to the shop with my XK8, they had no time to look at the XJS but when I started the XJS the brake pedal was firm like nothing ever happened and both lights come on and off as they should. I will take her to my normal Jaguar mechanic tomorrow if the pedal is hard and after I check how long the ABS light takes to turn off followed by the park brake light.
Can someone try to explain what went wrong with the braking system? I believe there is a backup system operating on at least two wheels

Thank you for your time.

Michel SFJC

Submitted by desp8838@bells… on Tue, 12/25/2012 - 16:28

Steven,

Thanks for your input, here is the complete story:
Front right caliper was partially seized, so brakes were applied in the R F wheel, disc got red hot, brake fluid boiled and lost its property therefore no brakes.
After seating for four hours the brake fluid returned to normal temperature, and I had brakes again. So the following repairs were performed: new discs, new calipers, new pads, new brake hoses the system was flushed and new fluid was added.

Cheers.

Michel

Submitted by stevejag@sbcgl… on Wed, 11/28/2012 - 22:12

Well Andre, this is a tough one to help with long distance. You need an assessment of this system by someone familiar with the Teves MkII brake system. I suspect you have an issue with either the Brake Actuation Unit or the Valve Block. The actuation unit equates to the master cylinder, but it also incorporates the hydraulic brake assist functions. The valve block is the rectangular item below the actuator with all the brake pipes attached to it. The pedal going to the floor is a possible symptom of both of these items, neither are inexpensive, though I'm pretty sure the valve block is the lesser of the two. The idea that it miraculously repaired itself also makes me lean toward the valve block.

Damn trouble is, for anyone to pin it down, it's going to have to occur for them.

Good luck!