[xj-s] Brake Accumulator

I’d like to report a successful brake repair.

As you know from my previous note, Edwina ('89 XJ-S Convertible) gave me
a fit on the way to work, making me really really sweat while the brake
pedal was near the floor for each and every stop (and once didn’t do a
thing at the floor).

First, and foremost, shame on ME! I’ve known for a while now that the
brake accumulator was not in good shape. Long ago, I wrote asking about
the brake pump being more “active” than it used to be. (2-3 seconds
running, every two stops or so). It was not getting much worse, perhaps
to needing it every 1.5 stops or so. THIS WAS MY CLUE. I ignored the
clue, trying to find better uses for the $200.

Tuesday morning, the brake accumulator finally died completely, and gave
me symptoms of a master-cyl failure. The truth is, we don’t have a
“master cyl” as-per-se. In the ABS world, we have a valve-block
(somewhat as complex as an automatic transmission), and an accumulator
and pump. The valve block is about $1,500. (eeek!!)

I followed the direction of the group in replacing the accumulator. I
really hate brake fluid on paint, so I kind of overreacted. I got a
bucket of warm water (to help wipe up any spray), and covered the
fender, and painted areas nearby with bath towels. I put a rag around
the base of the accumulator, like a tourniquet. I pumpued the brakes
about 50 times. I used an 8mm socket (called a 8mm hex brake caliper
bit, GM uses these for their calipers) and gave it a good grunt.

As the accumulator was so very failed, no spray came out AT ALL. I put
the new one on, it pumped up, and I got my brake pedal back. My
mechanic is going to do the bleed for me next week. I’m following
Chad’s advice on bleeding out the brake system and giving it fresh
blood.

Lesson Learned: You can ignore the ABS for about three or four months,
but WHY TAKE THE RISK?

Rusty. '89 XJ-S, '67 420.

Rusty Beard wrote:

The truth is, we don’t have a “master cyl” as-per-se. In the ABS world,
we have a >valve-block (somewhat as complex as an automatic transmission),
and an accumulator
and pump.

Well…the ABS cars do have a master cylinder. It is incorporated into the
"actuation assembly. I was horrified to realize that there is no seal kit
for it, so when it wears out like a master cylinder eventually will, you
have to replace the whole thing. Apparently there are no rebuilt ones
available. (Anyone know otherwise?)

What the Jaguar ABS cars don’t have at all, is a vacuum servo for the power
brakes.
(By the way, not having a separate master cylinder is not normal. Other ABS
cars have servos and master cylinders.

From: “Peter Cohen” petercohen@unn.unisys.com
Well…the ABS cars do have a master cylinder. It is incorporated into the
"actuation assembly. I was horrified to realize that there is no seal kit
for it, so when it wears out like a master cylinder eventually will, you
have to replace the whole thing. Apparently there are no rebuilt ones
available. (Anyone know otherwise?)

What the Jaguar ABS cars don’t have at all, is a vacuum servo for the power
brakes.
(By the way, not having a separate master cylinder is not normal. Other ABS
cars have servos and master cylinders.

And, apparently, so do some later XJ-S’s! I looked at a 6-cyl at
dealer, and it had what looked like a fairly conventional master
cylinder on the driver’s side of the engine compartment and a
separate motorized assembly on the passenger’s side, plumbed into the
lines.

– Kirbert | If anything is to be accomplished,
| some rules must be broken.
| - Palm’s Postulate