Yesterday I went for a ride in the 89 xjs. This Idiot pulled out right in front of me. I hit the brakes as normal, it stopped as normal, but the ABS light came on. I'm 20 miles from home, and the brakes were working fine. The next time I tried to stop the car, the pedal worked as normal, but the car wouldn't stop. I had to put the car in neutral, and STAND on the brakes for the car to slow down. When I got the car home, the fluid was down a pint. Added fluid, no change. And to make matters worse, I can't find my service manual anywhere. I had my wife put the ignition switch on, and the ABS motor came on. There is NO fluid leaking anywhere! Where did the fluid go? I check all the fluids before I take the car for a run, and it was full before I left. Any help PLEASE!..... It's a Teves MK3 system.

 

Could you have a bad line or caliper?

 

I'd investigate the accumulator ball first. The fluid likely is no longer being displaced by accumulator ball pressure. Be sure to depressurize the system with 30 break pumps while the car is off before you change it

 

Odd incident. Please post if you get an answer why this happened. Thanks.
RagJag

 

Sounds like he blew a brake line somewhere on the car... This happened to me on one of my collector cars. I had to hit the brakes hard and this happened.

 

Since the first post, I removed the ABS system, cleaned the screen, sprayed penetrating fluid into it and left it full over night. (thinking maybe a stuck valve) Since I still can't find my service manual, this is about all I could do. There is NO brake lines leaking, NO fluid dripping from anywhere! The brake pedal works just like it should, but when it gets to the point where the brakes should activate, it's like I'm trying to push my foot through a wall. I think the ABS pump might have been plugged, but that still don't explain the fluid loss. If the seal between the master cylinder and the booster went bad, this might explain that the fluid went into the booster, making the pedal HARD, but that don't explain the ABS light! I'm putting the ABS back on right after this post, I'll let you guy's know how it went.

 

OK... Put the ABS system back on, and couldn't get it to bleed because the ABS wasn't getting fluid! Took the brake line from the master cylinder to the ABS off, started the car, pushed the brakes, and nothing came out of the line. The brakes were just like they was, HARD! (explains the ABS light) SO... Anyone having a service manual, there has to be some kind of valve jammed in the master cylinder?

 

Nothing will come out of the rear line when you push the brakes. I have a 89, and when I rebuilt my brake system, I became frustrated fast. You have to press the brake pedal, then get turn the switch on. The ABS motor pushes the fluid out. On top of that, I have to question the accumulator as well. Did the brake fluid go into the accumulator ball? Maybe the diaphram ruptured internally. There is a specific procedure for bleeding the brakes on these cars. Its on this forum somewhere.

 

I also had a problem with the ABS on my Teves Master Cylinder, although I'm not an expert and this is more of a guess.

It could be one of the Valves in the ABS is not opening, which could be the result of a broken electric wire within the System.

So before you start pulling your hair out and pulling it all to bits, there is an electronic test that you can do, to determine if the Valves are working or not.

So have a look at this Post by djinaustin which explains amongst other things how to do this test.

As for the mystery of the missing brake fluid, could back pressure have forced it out of the breather hole in the Brake Fluid reservoir?

Please let us all know how you get on.

https://www.jaguarforums.com/forum/x...l-left-113913/

 

I have noticed more than one forum member stating that the rear brakes will not work if the ABS motor doesn't run. Is that true?! Seems to me that a brake system relying on a pump to work is unsafe. Said pump depends on an electrical system with fuses to run. Please say it ain't so, someone.
RagJag

 

I thought the system was split diagonally: if something failed, 1 front and 1 rear brake on opposite sides of the vehicle would still function. Could be wrong but I'm certain I've read this someplace.

 

Flint Ironstag. If I should decide to keep this XJS I am considering removing the ABS. The older cars did just fine without this junk. I just am not at all sure that the rear brakes would get no hydraulic pressure from the brake pedal if the ABS pump is not running. If true, we are all driving around in a 4,000 lb threat to ourselves and other people. I suppose I could pull the plug on the ABS and then slam on my brakes to see if the rears are braking.
So much of the trouble we experience with the XJS is due to government mandated devices to do things we all could do ourselves perfectly well and did for 70-80 years.
RagJag