Yesterday, while driving in afternoon Atlanta traffic (!) I had
a sudden brake failure. The brake pedal would go almost to the
floor before finding a little braking action. I managed to keep
driving and after a while, the brakes returned to normal!?
Could this have been a master cylinder issue or an ABS issue? I
went out to the garage where I keep the car and the brakes felt
fine this morning. Checked the brake fluid resevoir and there
was no apparent loss of fluid. Any suggestions? By the way, the
front rotors and all of the brake pads were replaced in the
last 6 months or so. Any help would be appreciated!–
New XJS Owner
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In reply to a message from area51guy sent Thu 29 May 2014:
It would be helpful if we knew the year. It is recommended
that you add that information to your signature line.–
The original message included these comments:
In reply to a message from area51guy sent Thu 29 May 2014:
I assume you have ABS, but I don’t know what year your car is.
Anyway I had the same occasional brake issue as you described.
The culprit was the accumulator… round ball looking thing.
the only easy thing to replace on this car. When it would act up
the brake and/or abs lights would activate. Did you notice these
lights ?
Either way this would be the #1 suspect in my mind. after 25 years
there are 2 types of accumulators… Ones that have been replaced
and those that need replacing. Just an allen wrench, but I would
hit it with some PB blaster or wd-40 the night before to help loosen
Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
4
Yesterday, while driving in afternoon Atlanta traffic (!) I had
a sudden brake failure. The brake pedal would go almost to the
floor before finding a little braking action. I managed to keep
driving and after a while, the brakes returned to normal!?
Could this have been a master cylinder issue or an ABS issue?
Could be either.
Any suggestions?
Find a gravel road and test the ABS function. You should be doing
this once a month to “exercise” the valves in the system. Give us a
report on what you find.
BTW, Teves III ABS? Little accumulator ball? Has the ball been
replaced?
– Kirbert
// please trim quoted text to context onlyOn 29 May 2014 at 18:10, area51guy wrote:
In reply to a message from area51guy sent Thu 29 May 2014:
My bad! The car is a 1994 XJS Convertible. It has
approximately 84,000 miles on the clock. The previous owner
had the car for about 2 years and had about $5k worth of
repairs done during that time. The front end has been
rebuilt, new compressor and condenser for the a/c, new
Michelin tires, new front rotors and pads all the way
around. The car starts and runs well and gets about 25-27
mpg on the highway. The car does need a new top and one of
the brake light lens is cracked. Probably could use a new
set of shocks. Also, the handbrake is non-functional at this
time. I have sourced a replacement handbrake and will
install it over the next few days. So, while not perfect,
the car seems to be in pretty good shape with just a few
items to take care of. Thanks for the replies!–
New XJS Owner
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In reply to a message from area51guy sent Fri 30 May 2014:
Follow the advise given earlier and add this information to
your signature line.
Also, FYI, 1994 convertible could be 6 cyl or 12 cyl. Please
don’t assume we’d know
The brake system you have is the Teves III. I just added a
great deal of information about its operation in my album:
Do you hear the ABS pump running for about 30-40 seconds
after the car has sat overnight?
Do you have the ABS light on with the ignition on?
Doing the gravel test, as Kirby suggested will help purging
some dirt stuck in the solenoids but you must make sure the
pump is running/building pressure as it should.
Also, bleeding the brakes here is non-trivial, you may want
to check the rear.
Hope this helps,
Steve–
The original message included these comments:
My bad! The car is a 1994 XJS Convertible. It has
approximately 84,000 miles on the clock. The previous owner
had the car for about 2 years and had about $5k worth of
repairs done during that time. The front end has been
In reply to a message from area51guy sent Thu 29 May 2014:
When was the last time the brake fluid was changed? If it was
a hot day and the fluid was old, it could have a reduced
boiling point. Boiled fluid is a vapor and compressible.
When the fluid cools, it condenses and would work.–
Maynard 94 XJS V12 Coupe 91XJS(RIP) 86XJ6 78MGB 67MGB
Palatine, IL, United States
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In reply to a message from area51guy sent Thu 29 May 2014:
When was the last time the brake fluid was changed? If it was
a hot day and the fluid was old, it could have a reduced
boiling point. Boiled fluid is a vapor and compressible.
When the fluid cools, it condenses and would work.–
Maynard 94 XJS V12 Coupe 91XJS(RIP) 86XJ6 78MGB 67MGB
Palatine, IL, United States
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In reply to a message from area51guy sent Thu 29 May 2014:
Ok, just updated the signature line to include car info. It
is a 1994 XJS 2+2 Convertible, 4.0 six cylinder engine,
Brooklands Green paint and leather Barley interior. The car
has about 84,000 miles on the odometer, verified by other
paper work and repair bills that I have on hand. Other than
the brake issue, the car starts and runs well. Everything
electrical seems to work properly, windows, top, cruise,
a/c, radio, in dash computer, dash/instruments and all
warning lights.
I haven’t listened for the accumulator pump up sound but
will do so in the morning. The brake fluid is fairly fresh
as the brakes were done and bled within the last 6 months or
so. All brake hoses appear to be in good condition. The
engine compartment is quite clean and all hoses, belts, etc
seem to be in good condition.
What the car needs: Top replacement, shock absorbers, oil
and filter change (will do on Saturday)and handbrake lever
replacement (I have a good one on hand). At some point I
will replace the leather on the front seats, repair the back
of the rear seat where the top window has scuffed the
leather and remove and clean the headlight covers.–
1994 Conv. 4.0, Brooklands Green w/Barley Interior
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In reply to a message from area51guy sent Fri 30 May 2014:
I wish I had an idea for you. Your scenario would be frightening!
I would recommend at least flushing and changing the brake fluid.
I have purged 2 Teves 3 systems this year, and both were absolutely
filthy inside. Something about the system causes dark sludge to
build inside the reservoir and all the other components.
Beyond that, I don’t know what you can do…a thourough check for
leaks maybe.–
John. '95 XJS 6.0L convertible. Southlake, TX
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// please trim quoted text to context only
Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
11
Something about the system causes dark sludge to build
inside the reservoir and all the other components.
That means there are rubber seals or hoses that are not compatible
with the brake fluid. It’s not good, and eventually will lead to
problems far more serious than dark sludge. Somebody needs to figure
out which components are incompatible so we can find a compatible
replacement part.
– Kirbert
// please trim quoted text to context onlyOn 30 May 2014 at 22:45, CJ95 wrote:
In reply to a message from Kirbert sent Sat 31 May 2014:
Besides 5k in repairs do you know if the previous owner
put any new MILES on the odometer or was the car parked up
for the past few years?
The exact same thing happened to me and a few others on
here and there are a few threads on the issue on these
forums, try a search for it.
If your handbrake is not working (like on mine) and the
parking brake light is on (like on mine) in traffic when
the engine temps are really high (like on mine) the pedal
would drop to the floor (like on mine) and you’d try
frantically to ‘‘pump it’’ some and just get enough action
not to smash into the guy infront (like me). ABS light
would be flashing at that point.
Well there are many theories but the first thing would be
to get the handbrake working, probably the spring is
missing and levers need a bit of grease or something
simple like that.
Second try and flush the system and replace as much of the
old brake flud with new.
Third new ball (accumulator is its name) if you don’t hear
the pump buzz for longer than 5 seconds on first startup
of the day.
Fourth the car needs to be driven and provoked (regularly)
on gravel to give the system some excercise. Some peoppe
think its stuck pistons from lack of action. I have a
rebuild kit with seals and other things but never
installed it since my brakes never acted up again after I
started driving it daily.
This issue mostly happens to cars that are not driven
regularly and I think that its the combination of all the
tings listed above. It happens a few times and goes away.
It’s comforting to have a working handbrake when it does
though.
You definitely need to put some miles on the car, drive it
daily if you can. It may be difficult to trust it now that
it has shown you an ugly side but you have to.–
'91 xjs v12 5.3 early facelift in BRG
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In reply to a message from Pele sent Sat 31 May 2014:
‘‘Fourth the car needs to be driven and provoked (regularly)
on gravel to give the system some excercise.’’
A wet road works just as well, but try to do your ABS
exercises clear of traffic.–
lockheed 92 XJS Cpe/97 LT1 Miami FL/ 96 XJS Cv 4.0 Austin TX
Austin, TX, United States
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// please trim quoted text to context only
Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
14
A wet road works just as well, but try to do your ABS
exercises clear of traffic.
Heck, a dry road works just as well, but the point of the gravel is
not to damage your tires. A wet road might, I dunno.
– Kirbert
// please trim quoted text to context onlyOn 31 May 2014 at 4:05, lockheed wrote:
In reply to a message from Kirbert sent Sat 31 May 2014:
I was going to suggest ice but then it hit me like a bolt
of lightning - where does one find a stretch of icy road
in june? Maybe in siberia somewhere, who knows…–
'91 xjs v12 5.3 early facelift in BRG
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In reply to a message from Pele sent Sat 31 May 2014:
You guys are scaring me! I drive my car hard and every
day to/from work. I don’t think the parking brake is
going to help me if my pedal goes to the floor during rush
hour on a Texas freeway. If it happened just once my car
would be parked till I figured something out. Braking is
one system I will not tolerate problems.
I am a firm believer that the worst thing you can do to
any equipment is to park it for months at a time. Seals
dry out and electrical contacts corrode. Every car I have
gets driven at least once a month, and I work all of the
equipment.
Also, everybody mentions listening for the ABS pump. I
have run one on the bench, and it is virtually silent. I
have never been able to hear it in the drivers seat. I
have to open the bonnet to tell if it’s running. Of
course the lights are an indication.
A flashing or solid ABS light indicates a control fault.
A solid light could also be low system pressure. It is
possible for the dump solenoid to actuate to release all
brake pressure. If it is dumping due to a wheel that’s
not turning, the pedal is supposed to kick back at your
foot to alert you that it’s operating.
It sounds to me like the dump solenoid is releasing on you
guys. That would have to be due to a control fault, if
that is, in fact, what’s happening. It takes an active
fault to trigger the solenoid…in other words a bad
connection will not cause it. It would have to be a bad
module.
Another possibility…and the one I personally would
persue first…is that dirt is getting lodged
intermittently in one of the master cylinder seals,
allowing the pedal to drop. A thorough cleaning might
help, but if it’s that dirty it may be too late.–
John. '95 XJS 6.0L convertible. Southlake, TX
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In reply to a message from CJ95 sent Sat 31 May 2014:
Hi John:
You are scaring me – after an overnight stay, if I turn the
key to ON and wait – my pump can be clearly heard running
from the driver seat. The buzzing sound goes away in 30-40
sec.
With the engine running, the pump cannot be heard. However, I
can hear the relay clicking in the passenger side footwell.
That means either:
my components are too noisy
my ears are too sensitive
I’d argue it’s not the the latter, thus, my worry is that my
ABS pump has seen ‘‘better days’’ and could be on its way out
How many Teves III owners can hear their ABS pump under the
conditions I described above?
Thanks,
Steve–
The original message included these comments:
You guys are scaring me! I drive my car hard and every
Also, everybody mentions listening for the ABS pump. I
have run one on the bench, and it is virtually silent. I
have never been able to hear it in the drivers seat. I
have to open the bonnet to tell if it’s running. Of
course the lights are an indication.
In reply to a message from sbobev sent Sat 31 May 2014:
Hi Steve
The test I did was switch ignition on and pump will run for
up to about 40 seconds and stop. Then straight after the
pump stops if your sphere is good you should be able to hit
the brake pedle 3 to 4 times one after the other untill the
pump runs . If the pump runs after the first press your
sphere is dead and after two is on its way out.
Remember the test is firm hard presses one after the other
will give you your spere status .
Remember 10% gas lost per year so after 10 years they are
all in a poor state I expect.
ps if you do replace the spere remove the complete pump
hold it in a vice between two blocks of wood and you can
then put all the force require to remove it without damage.–
The original message included these comments:
You are scaring me – after an overnight stay, if I turn the
key to ON and wait – my pump can be clearly heard running
from the driver seat. The buzzing sound goes away in 30-40
In reply to a message from area51guy sent Thu 29 May 2014:
Ok, got the handbrake freed up and took a look at the rear
brake rotors, pads and parking brake shoes. The pads look to
be new, but the rotors and parking brake shoes are pretty
much toast. I was able to pick up a new set of rear rotors
locally, but had to order the parking brake shoes. Once they
arrive, I will clean up the hubs, install the new parts and
adjust the parking brakes.
Meanwhile, getting back to the brake failure issue, when I
first turn on the ignition, the ABS brake warning light
comes on. After starting the engine (for first time of the
day), the ABS warning light will stay on for about 15-20
seconds or so before turning off. I believe that is telling
me that the accumulator and pump are working properly. Will
do some more investigating once I get the rear brakes back
together. Thanks all for the input!–
1994 Conv. 4.0, Brooklands Green w/Barley Interior
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In reply to a message from sbobev sent Sat 31 May 2014:
Steve, both my car ABS pump and the spare I bought make what I
would describe as a ‘‘whirring’’ sounds when they run. Definitely a
long way from what I’d call a ‘‘buzz’’. I have tried many times to
hear it in the driver’s seat, but cannot. When I turn the key on,
I get the AC blower and hear several relays (one even makes a
weird ‘‘boing’’ sound), so I am sure one of those is for the ABS
pump, but I’ve never tried to isolate the clicks. I’ve tried
opening the door with the AC off, but then the door bell chimes,
and I still can’t hear the pump.
The pump is rubber mounted…is there a chance your pump is rubbing
against something nearby to amplifiy the sound?–
The original message included these comments:
key to ON and wait – my pump can be clearly heard running
from the driver seat. The buzzing sound goes away in 30-40
sec.