I think if you ask Phil Prince at Motorcars Unlimited, he will say the same
thing regarding the accumulator. It is an Extremely common problem with the
'87, '88 and '89 XJ40 with the Girling braking system. Also go to
and search the archives for "accumulator" You are best
off searching the Moderns group since your symptoms were discussed for
months, 4-5 years ago.
Get an after market unit. They generally run $250-$300 depending. You want
the JLM11659 NOT the JLM1904. The JLM1904 is for the 1990-1994 Teves
system and won't work on your 3.6 litre. I bought mine from these guys
back in 2001. I bought the JLM11659R
because it was less AND it is rechargable. It also carries a slightly
higher pressure so the pump cycles less. Current price is $192USD plus
around $10USD shipping. I would think you can get the same deal or close
here in the States.
Another easy test, although not AS easy, is to pump the brakes til they get
hard and then simply remove the accumulator. You will lose very little
"Green Blood" Take a pencil and with the ERASER end of the pencil, slide it
into the opening. If it goes much past the threaded collar and into the ball
itself, you need a new accumulator. With 1200 PSI on the other side of the
neoprene diaphram, the eraser should hit rubber nearly immediately after
entering the chamber itself.
In terms of the problem being with the booster -- it is possible -- but I
doubt it. I have yet to hear of a booster being a problem with these cars,
but I am sure someone - some where has had the problem. The accumulator,
however IS a common problem.
In terms of doing re-solder work. I have often wondered, after spending
time on these cars, how the Brits keep aircraft in the air!! Usually, if
you are having a bulb failure warning, it is the module that needs a
re-solder. Anti-lock is usually the tall relay by the petrol inlet in the
boot. Pads low usually means the wire has broken on one of the 4 sensor
wires. The clock re-setting to 12 is re-solder. Usually anything involving
a circuit board can be corrected with a re-solder.