[modern] Re: Brakes

Disused Categories Modern
1

Thanks for the prompt reply… I cleaned all the ABS sensors this morning,
no change. Tried some panic stops on dry pavement, too. I was able to lock
'em up on dry pavement, so I’m pretty sure something’s awry with the ABS
system. Accumulator and relay checks are next.

Dave wrote:

+AD4-That would be unusual, have you tested your accumulator? Procedure is on
the
+AD4-XJ40 web page.

Thanks for the reference. I haven’t been to the XJ40 page in a good while.

+AD4-ABS sensors are at all four wheels, it’s the pad wear sensors that are LF
and
+AD4-RR on your car.

Yep+ACE- I remembered that as soon as I took the wheels off. Duh…

Grady
90XJ40

2

Grady wrote:

With engine running, the pedal seems spongy and will gradually leak down
to
the floor. With power off, pedal is solid. The brakes work ok as long as
you make gentle stops, but I sense that if I really need to stop quickly,
I’d be in trouble.

The pedal going to the floor with constant hard foot pressure at a standstill
is normal, it won’t happen when the car is moving, so don’t worry. The
general soft pedal when running could be air in the system, soft brake hoses
at the four wheels, or some other problem. I’d suggest you test you ABS
system by making a simulated panic stop, maybe the next time it rains, or
even on dry pavement. I think you’ll be amazed at how quickly you stop.

I suspect that the ABS valves are leaking, perhaps due to a faulty sensor
input.

That would be unusual, have you tested your accumulator? Procedure is on the
XJ40 web page.

I recall some discussion in past months about sensors getting dirty
and connectors failing, so that’s what I’m gonna chase next. If someone
familiar with this issue has a minute, remind me where they are… LF & RR
or vice versa?

ABS sensors are at all four wheels, it’s the pad wear sensors that are LF and
RR on your car.

Dave Lokensgard
'55 XK140 OTS
'86 Volvo 740 Turbo
'90 Burgundy Sovereign 4.0L (PATZCAT)
'90 Majestic
Poway, California

3

JJ,
If your car is the base XJ6 model, you dont have the hydraulic suspension,
and you have the electric pump for the brakes.
The accumulator is the black ball by the master cylinder.
It stores hydraulic pressure using a diaphragm with high pressure nitrogen
on one side, fluid on the other.
If you release the pressure by stepping on the brake pedal till it
gets hard, you can unscrew it with a lot of effort.
(It DOES come out)

To test it, turn the key on and wait for the alarms to clear…you
should hear the pump running.
After the alarms go out and the pump stops, turn the key off and pump
the brake pedal till it gets hard.
A good accumulator will go 15 to 20 pumps. A bad one will do one.
If you have the electric pump, and the accumulator tests ok, its a
problem with the pressure switch on the back of the electric pump.
It has a big blue connector going to it, and the switch itself is gold.
The connections on the switch itself can rot away.
Mine did this, and I soldered wires directly onto it 3 years ago, as
I did not want to spend $260.00 for a new switch.
Its been fine since I did that.

If your car has the hydraulic system, it has an engine driven pump,
and the engine has to run to pump up pressure.
There is a complete test sequence on the web page for that system.
Its more complex, with various valves and pressure switches…
Accumulators fail often on those systems.

Brett
1990 XJ6

…From: JGianquint@aol.com
Date: Fri, 16 Jul 1999 10:41:09 -0400 (EDT)
Subject: Re: Brakes
To: @Brett_Gazdzinski1

Brett
Sorry, but my aerospace engineering foundation seems to recall that the term
“accumulator” would generally refer to vacuum. However, in other fields,
the term would also be used to describe a device which would acculumlate
pressure. My Jag is a '91 XJ6 (40) and has been flashing the indications
which I described i.e., anti lock and brake, most of the time when the brakes
are applied.
Regards, JJ

4

Brett,

The Ferodo pads I just put on my car also have the beveled edge
on one side. They had a non-sticky anti-squeal layering on each
pad. In addition, I applied a coat of spray-on anti-squeal compound
which does stay sticky. I took it for a short test drive and they are
very quiet and smooth.

I had replaced the pads with Ferodos shortly after acquiring the
car and they lasted about 30,000 miles. For such a heavy car
that seems to be acceptable to me. I doubt you will get any more
than that with the Jaguar pads. In fact, the Jaguar pads are
probably a softer compound and won’t last as long.

Now, if I can just figure out which way the beveled edge should
go, I will have have some piece of mind. I put the bevel on the
trailing edge (bevel at top on front wheels) thinking that I would not
want to have a rock or sand wedged under the pad due to the
bevel. There were no instructions to indicate which way they
should be mounted. I ended up doing it the way they seem to
show in the pictures in the Haynes manual. From what I
could tell, they were working on front brakes and had the bevel
on top. Any thoughts?-

Pete Crosby (@Pete_Crosby)
In the sunny southland (Marietta, Georgia, USA)
'88 BRG XJ40
'60 BRG MKII

5

Pete,
The ferodo pads I got had beveled edges on both sides…
They also had that nice blue fiberglass backing…it eliminates the
need for the sticky stuff…

I put my beveled edges at the counterclockwise direction…like
the brakes on a bike…trailing edge touches first…

I suspect the pads are softer…they stop better, and I would rather
wear out pads then rotors…

So far, they are very nice…

Brett
1990 XJ6
…Date: Fri, 08 Oct 1999 15:26:34 -0400
From: Pete Crosby pac@atl.hp.com
Subject: Re: Brakes
To: modern modern@jag-lovers.org,
Brett Gazdzinski <@Brett_Gazdzinski1>

Brett,

The Ferodo pads I just put on my car also have the beveled edge
on one side. They had a non-sticky anti-squeal layering on each
pad. In addition, I applied a coat of spray-on anti-squeal compound
which does stay sticky. I took it for a short test drive and they are
very quiet and smooth.

I had replaced the pads with Ferodos shortly after acquiring the
car and they lasted about 30,000 miles. For such a heavy car
that seems to be acceptable to me. I doubt you will get any more
than that with the Jaguar pads. In fact, the Jaguar pads are
probably a softer compound and won’t last as long.

Now, if I can just figure out which way the beveled edge should
go, I will have have some piece of mind. I put the bevel on the
trailing edge (bevel at top on front wheels) thinking that I would not
want to have a rock or sand wedged under the pad due to the
bevel. There were no instructions to indicate which way they
should be mounted. I ended up doing it the way they seem to
show in the pictures in the Haynes manual. From what I
could tell, they were working on front brakes and had the bevel
on top. Any thoughts?

Pete Crosby (pac@atl.hp.com)
In the sunny southland (Marietta, Georgia, USA)
'88 BRG XJ40
'60 BRG MKII

6

I also have Ferodo pads fitted. On the '88 the inner pad has the wear
indicator attached so this will only fit one way and the other pad in the
box only fits one way in the outer position. Mine were bevelled but I cant
think now which way round I put them - it was hobsons choice so I didnt give
it much thought.
They brake well but do give the little “graunch” when the brakes are just
lifted off.

Nigel Stone
1988 Sovereign 116K
Coventry, UK>From: “Pete Crosby” pac@atl.hp.com

To: “modern” modern@jag-lovers.org, “Brett Gazdzinski”
Brett.Gazdzinski@wcom.com
Subject: [modern] Re: Brakes
Date: Fri, 8 Oct 1999 15:26:34 -0400

Brett,

The Ferodo pads I just put on my car also have the beveled edge
on one side. They had a non-sticky anti-squeal layering on each
pad. In addition, I applied a coat of spray-on anti-squeal compound
which does stay sticky. I took it for a short test drive and they are
very quiet and smooth.

I had replaced the pads with Ferodos shortly after acquiring the
car and they lasted about 30,000 miles. For such a heavy car
that seems to be acceptable to me. I doubt you will get any more
than that with the Jaguar pads. In fact, the Jaguar pads are
probably a softer compound and won’t last as long.

Now, if I can just figure out which way the beveled edge should
go, I will have have some piece of mind. I put the bevel on the
trailing edge (bevel at top on front wheels) thinking that I would not
want to have a rock or sand wedged under the pad due to the
bevel. There were no instructions to indicate which way they
should be mounted. I ended up doing it the way they seem to
show in the pictures in the Haynes manual. From what I
could tell, they were working on front brakes and had the bevel
on top. Any thoughts?

Pete Crosby (pac@atl.hp.com)
In the sunny southland (Marietta, Georgia, USA)
'88 BRG XJ40
'60 BRG MKII

Get Your Private, Free Email at http://www.hotmail.com

7

Nigel,
The 1990 and newer cars have a different setup, with a removable sensor
(that breaks when you try to remove it), so the pads can go in either
direction…
I have found the Jaguar pads have eliminated the ‘graunch’ completely
on my car…smooth and quiet all the time.

I can SOMETIMES get the noise if I try…letting the car move .001
MPH, but only sometimes, and I don’t think the brakes are bed in yet.

This in itself is well worth the $20.00 extra a set the Jaguar pads
cost!

I did some driving around in the last few days, and Farquar has not
been this nice in some time…very smooth and quiet, driveshaft/tires
seem to be ok, trans shifting nice, brakes smooth as glass, engine
running fantastic…

The only flaw is the tire noise off the P4000,s…
Other than that, WOW!

In order to get here though, I have found that I had to ditch the brembo
rotors and ferodo pads…I wish I could ditch the wretched p4000,s.
Anyone want to buy 5 new ones in the new Jersey area?
215-65-vr15 for $40.00 each? Make me an offer!

This is one case where I wish the tires wore out fast, as I don’t want
to listen to this crap for 30,000 miles!

Brett
1990 XJ6
…Date: Mon, 11 Oct 1999 02:12:43 -0700 (PDT)
From: Nigel Stone njstone@hotmail.com
Subject: Re: [modern] Re: Brakes
Sender: owner-modern@jag-lovers.org
To: modern@jag-lovers.org

I also have Ferodo pads fitted. On the '88 the inner pad has the wear
indicator attached so this will only fit one way and the other pad in the
box only fits one way in the outer position. Mine were bevelled but I cant
think now which way round I put them - it was hobsons choice so I didnt give
it much thought.
They brake well but do give the little “graunch” when the brakes are just
lifted off.

Nigel Stone
1988 Sovereign 116K
Coventry, UK

From: “Pete Crosby” pac@atl.hp.com
To: “modern” modern@jag-lovers.org, “Brett Gazdzinski”
<@Brett_Gazdzinski1>
Subject: [modern] Re: Brakes
Date: Fri, 8 Oct 1999 15:26:34 -0400

Brett,

The Ferodo pads I just put on my car also have the beveled edge
on one side. They had a non-sticky anti-squeal layering on each
pad. In addition, I applied a coat of spray-on anti-squeal compound
which does stay sticky. I took it for a short test drive and they are
very quiet and smooth.

I had replaced the pads with Ferodos shortly after acquiring the
car and they lasted about 30,000 miles. For such a heavy car
that seems to be acceptable to me. I doubt you will get any more
than that with the Jaguar pads. In fact, the Jaguar pads are
probably a softer compound and won’t last as long.

Now, if I can just figure out which way the beveled edge should
go, I will have have some piece of mind. I put the bevel on the
trailing edge (bevel at top on front wheels) thinking that I would not
want to have a rock or sand wedged under the pad due to the
bevel. There were no instructions to indicate which way they
should be mounted. I ended up doing it the way they seem to
show in the pictures in the Haynes manual. From what I
could tell, they were working on front brakes and had the bevel
on top. Any thoughts?

Pete Crosby (pac@atl.hp.com)
In the sunny southland (Marietta, Georgia, USA)
'88 BRG XJ40
'60 BRG MKII

Get Your Private, Free Email at http://www.hotmail.com

8

If the ABS is activating frequently then one wheel is doing most of the
work and the ABS is trying to redistribute the load out.

The ABS does not engage on a dry road unless I am comming down from
90mph - fast.

The ABS does work quickly on wet leaves. My new tires have cut ABS
usage significantly on wet roadways.

Go check the brake calipers yourself. The job is easy for a novice.
You knew you would one day buy that complete Husky socket set for
$140.00 at Home Depot. The 1/2" torque wrench runs about $50.00.

Christoph Hanau
1990 XJ40 135K “The Mistress”

9

Jerry,
I would suspect some air in the system.
After you were done with fitting the new pads, you should bleed about
a quart through the system to get all the dirt and air out.

Start with the back brakes, then do the fronts.

You might also remove the wheels and watch as someone pushes the brake
pedal to make sure its not a mechanical problem with calipers or
something else.

To post to the list, you have to post from the exact same e mail address
as you subscribed with, and no attachments.
Your mail to me did not have attachments, so I would guess its your
e mail address.

Brett
1990 XJ6
…From: HAGHY@aol.com
Date: Thu, 23 Dec 1999 03:36:09 -0500 (EST)
Subject: Re: Brakes
To: @Brett_Gazdzinski1
Message-id: 0.248815cd.259338f9@aol.com

Dear Brett,
I tried sending this email to the list about 4 times now and it isnt
being posted. I dont know whats wrong but I though I might ask you since its
quite important. I replaced the brake pads a few days ago and now the brake
pedal goes down much farther than its supposed to and the car stops
sluggishly. I looked through the haynes manual and in the troubleshooting it
said that the brake booster might be faulty…but why would it go bad after
I changed the pads? Anyways, I dont think that the booster is bad, however, i
did bleed some fluid to push back the calipers to get the new thicker pads
in. I watched the reservoir as I depressed the brake pedal several times with
the engine running to see if the system would suck some fluid back in to the
lines. The level of the reservoir is still the same. I had to bleed some
fluid because there was no way the new pads were gonna go in. What do I need
to do? I added about 1/4 cup of brake fluid to the reservoir to top it off,
but the pedal still goes down far.

Thanks much and happy holidays,

-jerry