I replace my ABS pressure delay valve by removing the two
lines that are attached to it and swapping it out with a new
one. I figured that this introduced air into the system.
So I’m trying to bleed the brakes. I’m starting with the
right rear wheel. After some 50 +/- pumps, hardly any brake
fluid has traveled out the bleeder valve (it is open).
Is there a special procedure during replacement of the ABS
pressure delay valve? Any suggestions? I really need to
get this car back on the road this weekend.
In reply to a message from jstjagguy sent Fri 3 May 2013:
What year and model do you have, might get better answers with
that info.
For my '89 XJS with ABS, you don’t pump the brakes you just
press down and the ABS pump does all the work. So if your ABS
pump isn’t working, no rear brakes - so back to year and
model…–
The original message included these comments:
So I’m trying to bleed the brakes. I’m starting with the
right rear wheel. After some 50 +/- pumps, hardly any brake
fluid has traveled out the bleeder valve (it is open).
Is there a special procedure during replacement of the ABS
In reply to a message from jstjagguy sent Fri 3 May 2013:
To bleed the rear brakes:
Raise and support the car as necessary to get to the rear
bleeder screws - make sure you can loosen/open them.
Find a stick, short board or 2x4 that you can put between the
front edge of the driver seat and the brake pedal that will hold
the brake pedal partially depressed - 3 inches or so. You can move
the seat fore or aft to help do this.
Top up your brake fluid reservoir.
Turn ignition key to run (Posn. 3?) - do not start engine. Your
ABS pump should run for a short period if the accumulator pressure
is low, and your ABS amber light and red brake warning should go
out. Leave ignition key on until you are done bleeding the rear
brakes.
Bleed your rear brakes one at a time - the ABS pump will supply
the pressure and volume. Do not let your reservoir get too low on
fluid.
When you are done bleeding, turn off the ignition, remove the
stick, and lower the car. Bleed the front brakes is the
traditional manner - do not let the reservoir get low. When done,
don’t forget to top up the brake reservoir.–
lockheed 92 XJS Cpe/97 LT1 Miami FL/ 96 XJS Cv 4.0 Austin TX
Austin, TX, United States
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In reply to a message from lockheed sent Sat 4 May 2013:
Wow, thanks for the quick feedback. I was really baffled
last night trying to figure this out. It is a 1995 XJS with
the traditional outboard brakes.
So as far as bleeding the rear brakes - I should simply keep
the pedal pressed, turn the ignition to the indent before
starting the car so that power is supplied, and then just
open the bleeder valve until clear fluid is running through
the line?
In reply to a message from jstjagguy sent Sat 4 May 2013:
Pretty much it, you should check the reservoir several times
during the process, don’t want to get air back in the line.–
The original message included these comments:
So as far as bleeding the rear brakes - I should simply keep
the pedal pressed, turn the ignition to the indent before
starting the car so that power is supplied, and then just
open the bleeder valve until clear fluid is running through
Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
6
In a related vein: The last XJ-S’s had a different type of ABS
system that once again featured the vacuum booster between the pedal
box and the master cylinder, restoring the look to similar to the pre-
ABS cars and getting rid of the overly-expensive Teves master
cylinder. Q: How do you bleed the rear brakes on THOSE cars?
In reply to a message from jstjagguy sent Sat 4 May 2013:
Kirbert has a valid point. The process I outlined was for the
Older ABS system with the accumulator sphere on the right side with
the hydraulic pump. What your '95 has depends on it production
sequence since the early ones had the older system. The change
over to the newer system happened sometime during the '95
production run. If you have the black spherical accumulator on the
right (psgr side) and the square reservoir on the left (drivers
side), you have the older system. The newer system has a triangular
reservoir with a typical vacuum booster on the left, and no black
accumulator sphere on the right. If you have the older system, my
procedure works. The newer system, I can’t say, as I have never
bled the brakes on the wifes '96. Perhaps someone who has bled the
newer system can offer a procedure.–
lockheed 92 XJS Cpe/97 LT1 Miami FL/ 96 XJS Cv 4.0 Austin TX
Austin, TX, United States
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In reply to a message from lockheed sent Sat 4 May 2013:
Thanks again for the detailed and quick feedback - this
forum is great!
Mine is an early production 1995 so it does have the older
Teves system with the vacuum booster. I’m at the last wheel
waiting for PB blaster to loosen the bleeder screw - so far
so good!
Can someone explain why bleeding the rear brakes requires
engaging power to the car while bleeding the front brakes
does not require this special procedure?
In reply to a message from Kirbert sent Sun 5 May 2013:
Ha, I realized that I incorrectly called the accumulator the
vacuum booster! To be clear, it is the earlier system with
the black accumulator on the passenger firewall.
Is there a way to edit posts? I wanted to edit it right
away but could not see an easy way to modify an old post
(same with the typo on my first post of this thread)?
The brakes are bled. I’ve unhooked the battery for over an
hour. The ABS pressure delay valve was leaking and has been
replaced. I’m hoping that this was why the ABS warning
light on the dash was illuminated.
In your experience, will unhooking the battery re-test the
car for failures once re-connected? If the warning light is
still on after re-connecting, can I be 100% sure that
something besides the ABS pressure delay valve was causing
the ABS warning light to come on? No one around here seems
to have the proper ABS scanner, except possibly the dealer.
In reply to a message from jstjagguy sent Sun 5 May 2013:
When you reconnect the battery, everything pretty much starts out
with a clean slate, and the ABS will be fault tested when the
ignition is turned on. A scanner is not necessary to read the ABS
faults. There is a three pin connector pigtail in the boot just
over the left wheel well area and just aft of the ABS ECU. I don’t
have the information currently on hand for testing with that
connector and the blink codes for the ABS light, but there is
plenty of that in the XJS archives. Search the Archives for the
XJS, ABS, Fault codes, with no particular poster or date and you
should come up with plenty.–
lockheed 92 XJS Cpe/97 LT1 Miami FL/ 96 XJS Cv 4.0 Austin TX
Austin, TX, United States
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