[xj40] Mystery Sound Solved?

XJ40
1

I posted some time back about a persistent annoying sound I
experience from time to time while driving down straight aways –
it’s a constant, steady squeaking that appears to be coming from
somewhere underneath the car. It comes and goes, and seems to
never be present in rainy weather. I’ve gone weeks w/o hearing it,
and then it suddenly reappears. It’s particularly noticeable while
driving alongside another car or when driving along adjacent to a
verticle surface (e.g. tall curb) that echoes the sound back to me.

I had suspected a wheel bearing going dry or worn, but in the
past year since it appeared it has not gotten any louder or more
frequent, in general, and does not appear when making turns.

The other day it dawned on me that the sound is very akin to what
I hear when I sometimes first depress my brake pedal, esp. the
first thing in the a.m. - a light squealing. This got me to
thinking that the mystery sound could be a brake shoe slightly
dragging or not retracting (e.g. b/c of bad or worn spring), but
then, as we all know, we have disc brakes all around on our XJ40s.

However, about a year ago I had to have the parking brake
tightened up b/c it would not pass the safety inspection. It
seemed fine to me, but the safety inspector said it did not hold
fast enough when under load. So, I had a friend of mine tighten it
up and it passed.

Is it possible the sound I’m hearing is the result of the parking
brake shoe dragging intermittently against the drum, even though
the light is not on? I’ve tried jiggling the brake handle while
going down the road to see if it makes any difference, but it
doesn’t (I don’t dare push the button and pull up on it at the
time, of course). (btw, I never use my parking brake).

What do you think?–
&:-)) Paul '88 XJ6 VDP 127k (and '90 XJS coupe on way
Garland, Texas, United States
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2

Hello Paul,

I hear a similar noise coming from my 88 and 89 XJ40’s. When I apply slight
pressure on the brake pedal, just to sit the pads against the rotors, the
noise disapears. Did you exprerience that?

regards,
Francois

I posted some time back about a persistent annoying sound I
experience from time to time while driving down straight aways –
it’s a constant, steady squeaking that appears to be coming from
somewhere underneath the car. It comes and goes, and seems to
never be present in rainy weather. > –

Paul '88 XJ6 VDP 127k >

Visit the Jag Lovers homepage at http://www.jag-lovers.org for exciting services and resources including Photo Albums, Event Diary / Calendar, On Line Books and more !

3

In reply to a message from AttyDallas sent Mon 28 Jul 2003:

Paul,

Your probably on the right track with your analysis. When was the
last time you checked / greased the caliper guide pins (sliders) on
your brakes? You may have one of those ‘hanging up’, not allowing
the outer pad to withdraw from the disc sufficiently.

Another thought occurs. You say you never use your parking brake
(whyever not?) but that may be the cause of your problem. The
friction surface of the parking brake drum (just like the rotors
themselves) will rust if not used. Only by application of the
parking brake will you keep the build up of rust to a minimum. If
you never use it, I can imagine a build up of rust sufficient to
fill the gap between the drum and the brake shoe, particularly if
you adjusted it to give minimum clearance to pass the safety
inspection.

Does no harm to yank the parking brake on a couple of times at low
speed to clean up the drum and pads. Don’t worry, it wont lock the
rear wheels and execute a ‘handbrake turn’ - it’s not that
effective! Just keep your finger on the button.

One final thought, have you checked that the inner brake shield is
not distorted and rubbing on the rotor?–
Bryan N ('91 Sovereign 4.0 L)
Cambridge, United Kingdom
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4

In reply to a message from F. Roger sent Mon 28 Jul 2003:

Hi Frenchie (ltns, btw),

Yes … the slight squeal that I get occassionally from my brakes
on first application usually disappears after the pressure is
increased and before the car comes to a full stop. I’ve wondered
if it might be due to condensation on the rotor(s), or a very
slight leak of fluid (although my fluid level is fine)onto the pads
or rotors that is ‘‘burnt off’’ or wiped off as the pad pressure is
increased. No other symptoms and no warning lights. I had the
pads replaced on the front two years ago when I bought the car.

However, I haven’t found any connection yet between that sound
and the mystery noise.–
&:-)) Paul '88 XJ6 VDP 127k (and '90 XJS coupe on way
Garland, Texas, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–

Visit the Jag Lovers homepage at http://www.jag-lovers.org for exciting services and resources including Photo Albums, Event Diary / Calendar, On Line Books and more !