Front Rotor Concern, 02 WJ

Hi All,
I went down under to do my first oil change on my '02 Grand Cherokee and to
get acquainted with the underside. I noticed the inboard side of both front
brake rotors appear as if the disc pad is not contacting them completely.
There is some shine/wear around the outside, oh, 3/4 inch or so and it
diminishes to about no wear toward the hub. I sense no braking problem in
the car at all. The outboard side of both rotors is shiny/worn equally as
you'd expect.
I thought I'd ask the group what your opinion of the malady is. I will of
course be pulling the calipers in a couple days to lube the pins and such,
but it seems odd that both sides would develop a problem at the same time.
Do I have a couple bum calipers all at once?
The car has 40K miles on it now. Was about 37,500 when I got her.
As an observation, they, DC, sure placed that oil filter in a bad spot. The
filter on my 93, 4.0 liter was on the passenger side and easily changed from
above. This one is underneath and is sure easy to get a faceful of hot oil
if you're not careful.
Thanks,
D

I believe you are looking at the steel plate that's bonded to the
brake pad, the open distance is how thick it is:
http://www.billhughes.com/WJCaliber.jpg Probably the easiest way to see
the actual thickness is to take the wheel off and look through the
caliper: http://www.billhughes.com/dana25knuckle.jpg
God Bless America, Bill O|||||||O


D wrote:
>
> Hi All,
> I went down under to do my first oil change on my '02 Grand Cherokee and to
> get acquainted with the underside. I noticed the inboard side of both front
> brake rotors appear as if the disc pad is not contacting them completely.
> There is some shine/wear around the outside, oh, 3/4 inch or so and it
> diminishes to about no wear toward the hub. I sense no braking problem in
> the car at all. The outboard side of both rotors is shiny/worn equally as
> you'd expect.
> I thought I'd ask the group what your opinion of the malady is. I will of
> course be pulling the calipers in a couple days to lube the pins and such,
> but it seems odd that both sides would develop a problem at the same time.
> Do I have a couple bum calipers all at once?
> The car has 40K miles on it now. Was about 37,500 when I got her.
> As an observation, they, DC, sure placed that oil filter in a bad spot. The
> filter on my 93, 4.0 liter was on the passenger side and easily changed from
> above. This one is underneath and is sure easy to get a faceful of hot oil
> if you're not careful.
> Thanks,
> D

Hi Bill,
No, no the actual brake rotor/disc itself is what I'm talking about. It
shows little or no wear. Mine is not evenly shiny where the pad contacts it
as the one is in the picture you sent.
Thanks.
Denny

"L.W.(Bill) Hughes III" > wrote in message
...
> I believe you are looking at the steel plate that's bonded to the
> brake pad, the open distance is how thick it is:
> http://www.billhughes.com/WJCaliber.jpg Probably the easiest way to see
> the actual thickness is to take the wheel off and look through the
> caliper: http://www.billhughes.com/dana25knuckle.jpg
> God Bless America, Bill O|||||||O
>
>
> D wrote:
> >
> > Hi All,
> > I went down under to do my first oil change on my '02 Grand Cherokee and
to
> > get acquainted with the underside. I noticed the inboard side of both
front
> > brake rotors appear as if the disc pad is not contacting them
completely.
> > There is some shine/wear around the outside, oh, 3/4 inch or so and it
> > diminishes to about no wear toward the hub. I sense no braking problem
in
> > the car at all. The outboard side of both rotors is shiny/worn equally
as
> > you'd expect.
> > I thought I'd ask the group what your opinion of the malady is. I will
of
> > course be pulling the calipers in a couple days to lube the pins and
such,
> > but it seems odd that both sides would develop a problem at the same
time.
> > Do I have a couple bum calipers all at once?
> > The car has 40K miles on it now. Was about 37,500 when I got her.
> > As an observation, they, DC, sure placed that oil filter in a bad spot.
The
> > filter on my 93, 4.0 liter was on the passenger side and easily changed
from
> > above. This one is underneath and is sure easy to get a faceful of hot
oil
> > if you're not careful.
> > Thanks,
> > D

Sure sounds like the caliper is sticking. It may have caused the other side
to overheat, glaze and/or perhaps warped the rotor.

Do you know if you have the Teves (early '02 black) or Akebono (late '02
Silver) calipers?

Do you get pulsations or shaking during braking?

Any pulling to one side or the other?

Noisy?

You will have to pull the wheel to get a look at it, preferably pull the
caliper too to get a good look

"D" > wrote in message
...
> Hi Bill,
> No, no the actual brake rotor/disc itself is what I'm talking about. It
> shows little or no wear. Mine is not evenly shiny where the pad contacts
> it
> as the one is in the picture you sent.
> Thanks.
> Denny
>
> "L.W.(Bill) Hughes III" > wrote in message
> ...
>> I believe you are looking at the steel plate that's bonded to the
>> brake pad, the open distance is how thick it is:
>> http://www.billhughes.com/WJCaliber.jpg Probably the easiest way to see
>> the actual thickness is to take the wheel off and look through the
>> caliper: http://www.billhughes.com/dana25knuckle.jpg
>> God Bless America, Bill O|||||||O
>>
>>
>> D wrote:
>> >
>> > Hi All,
>> > I went down under to do my first oil change on my '02 Grand Cherokee
>> > and
> to
>> > get acquainted with the underside. I noticed the inboard side of both
> front
>> > brake rotors appear as if the disc pad is not contacting them
> completely.
>> > There is some shine/wear around the outside, oh, 3/4 inch or so and it
>> > diminishes to about no wear toward the hub. I sense no braking problem
> in
>> > the car at all. The outboard side of both rotors is shiny/worn equally
> as
>> > you'd expect.
>> > I thought I'd ask the group what your opinion of the malady is. I will
> of
>> > course be pulling the calipers in a couple days to lube the pins and
> such,
>> > but it seems odd that both sides would develop a problem at the same
> time.
>> > Do I have a couple bum calipers all at once?
>> > The car has 40K miles on it now. Was about 37,500 when I got her.
>> > As an observation, they, DC, sure placed that oil filter in a bad spot.
> The
>> > filter on my 93, 4.0 liter was on the passenger side and easily changed
> from
>> > above. This one is underneath and is sure easy to get a faceful of hot
> oil
>> > if you're not careful.
>> > Thanks,
>> > D
>
>

Hi Denny,
That's nearly impossible to freeze a piston and not have it drag
and burn: http://www.billhughes.com/WJCaliber.jpg Take her in as see
what a mechanic says.
God Bless America, Bill O|||||||O
http://www.billhughes.com/

D wrote:
>
> Hi Bill,
> No, no the actual brake rotor/disc itself is what I'm talking about. It
> shows little or no wear. Mine is not evenly shiny where the pad contacts it
> as the one is in the picture you sent.
> Thanks.
> Denny

To get that wear pattern, there must be some combination of warped rotor
(dished in), bad or misseated pad, or caliper piston cocked over. I'd
tear it down, see what the inboard pads look like. At 40 k miles,
youshould have something like 1/2 wear on the pads, should be very
noticeable.

On the other hand, you may find very little wear, that would point to
frozen mounitng pins.

D wrote:

> Hi All,
> I went down under to do my first oil change on my '02 Grand Cherokee and to
> get acquainted with the underside. I noticed the inboard side of both front
> brake rotors appear as if the disc pad is not contacting them completely.
> There is some shine/wear around the outside, oh, 3/4 inch or so and it
> diminishes to about no wear toward the hub. I sense no braking problem in
> the car at all. The outboard side of both rotors is shiny/worn equally as
> you'd expect.
> I thought I'd ask the group what your opinion of the malady is. I will of
> course be pulling the calipers in a couple days to lube the pins and such,
> but it seems odd that both sides would develop a problem at the same time.
> Do I have a couple bum calipers all at once?
> The car has 40K miles on it now. Was about 37,500 when I got her.
> As an observation, they, DC, sure placed that oil filter in a bad spot. The
> filter on my 93, 4.0 liter was on the passenger side and easily changed from
> above. This one is underneath and is sure easy to get a faceful of hot oil
> if you're not careful.
> Thanks,
> D
>
>

You can't predict wear according to mileage, unless you know driving style
and where driven. It could be that the calipers are mounted on a slight
slant, to prevent squealing and grabbing, and that the pads just haven't
worn in that far yet. I would take it to a Jeep dealer and ask them if they
have seen it before. Of course, if the performance is good I would resist
buying new calipers, new rotors, new spindles, etc. unless they showed me
some kind of TSB or service manager's bulletin from the manufacturer. Maybe
there is a shim that can be installed.

For the faceful of hot oil buy some metal ramps or build a set out of
stacked two-by-sixes like I have. If you are older like Bill maybe
two-by-tens would be easier to see.

Earle

"RoyJ" > wrote in message
nk.net...
> To get that wear pattern, there must be some combination of warped rotor
> (dished in), bad or misseated pad, or caliper piston cocked over. I'd
> tear it down, see what the inboard pads look like. At 40 k miles,
> youshould have something like 1/2 wear on the pads, should be very
> noticeable.
>
> On the other hand, you may find very little wear, that would point to
> frozen mounitng pins.
>
> D wrote:
>
> > Hi All,
> > I went down under to do my first oil change on my '02 Grand Cherokee and
to
> > get acquainted with the underside. I noticed the inboard side of both
front
> > brake rotors appear as if the disc pad is not contacting them
completely.
> > There is some shine/wear around the outside, oh, 3/4 inch or so and it
> > diminishes to about no wear toward the hub. I sense no braking problem
in
> > the car at all. The outboard side of both rotors is shiny/worn equally
as
> > you'd expect.
> > I thought I'd ask the group what your opinion of the malady is. I will
of
> > course be pulling the calipers in a couple days to lube the pins and
such,
> > but it seems odd that both sides would develop a problem at the same
time.
> > Do I have a couple bum calipers all at once?
> > The car has 40K miles on it now. Was about 37,500 when I got her.
> > As an observation, they, DC, sure placed that oil filter in a bad spot.
The
> > filter on my 93, 4.0 liter was on the passenger side and easily changed
from
> > above. This one is underneath and is sure easy to get a faceful of hot
oil
> > if you're not careful.
> > Thanks,
> > D
> >
> >

It's really common up here in the rust belt Bill. The sliders and pins
get corroded and sticky easy. The ends of the pads even wear notches in
the slider jamming them up big time. Then the slider face has to be
rebuilt or replaced. They need a good lube job, better than the factory
does, that's for sure.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)

"L.W.(Bill) Hughes III" wrote:
>
> Hi Denny,
> That's nearly impossible to freeze a piston and not have it drag
> and burn: http://www.billhughes.com/WJCaliber.jpg Take her in as see
> what a mechanic says.
> God Bless America, Bill O|||||||O
> http://www.billhughes.com/
>
> D wrote:
> >
> > Hi Bill,
> > No, no the actual brake rotor/disc itself is what I'm talking about. It
> > shows little or no wear. Mine is not evenly shiny where the pad contacts it
> > as the one is in the picture you sent.
> > Thanks.
> > Denny

Since you mention that Mike, it brings to mind something else I noticed on
this WJ. I wash it in the driveway and notice that in 30 minutes the brake
rotors have patches of rust on the face. It disappears as soon as I drive
any distance, but if the setup is prove to corrosion, then that might be the
problem.
I just went out to look and the calipers are the black ones. Looks like I
might have a $300+ afternoon in the driveway coming up in the near future.
Dangit.
Thanks for all of you guyz input.
Denny

"Mike Romain" > wrote in message
...
> It's really common up here in the rust belt Bill. The sliders and pins
> get corroded and sticky easy. The ends of the pads even wear notches in
> the slider jamming them up big time. Then the slider face has to be
> rebuilt or replaced. They need a good lube job, better than the factory
> does, that's for sure.
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
> Canadian Off Road Trips Photos: Non members can still view!
> Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
> (More Off Road album links at bottom of the view page)
>
> "L.W.(Bill) Hughes III" wrote:
> >
> > Hi Denny,
> > That's nearly impossible to freeze a piston and not have it drag
> > and burn: http://www.billhughes.com/WJCaliber.jpg Take her in as see
> > what a mechanic says.
> > God Bless America, Bill O|||||||O
> > http://www.billhughes.com/
> >
> > D wrote:
> > >
> > > Hi Bill,
> > > No, no the actual brake rotor/disc itself is what I'm talking about.
It
> > > shows little or no wear. Mine is not evenly shiny where the pad
contacts it
> > > as the one is in the picture you sent.
> > > Thanks.
> > > Denny

That is flash rust, it means nothing...

(every vehicle gets it)

"D" > wrote in message
...
> Since you mention that Mike, it brings to mind something else I noticed on
> this WJ. I wash it in the driveway and notice that in 30 minutes the brake
> rotors have patches of rust on the face. It disappears as soon as I drive
> any distance, but if the setup is prove to corrosion, then that might be
> the
> problem.
> I just went out to look and the calipers are the black ones. Looks like I
> might have a $300+ afternoon in the driveway coming up in the near future.
> Dangit.
> Thanks for all of you guyz input.
> Denny
>
> "Mike Romain" > wrote in message
> ...
>> It's really common up here in the rust belt Bill. The sliders and pins
>> get corroded and sticky easy. The ends of the pads even wear notches in
>> the slider jamming them up big time. Then the slider face has to be
>> rebuilt or replaced. They need a good lube job, better than the factory
>> does, that's for sure.
>>
>> Mike
>> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
>> 88 Cherokee 235 BFG AT's
>> Canadian Off Road Trips Photos: Non members can still view!
>> Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
>> (More Off Road album links at bottom of the view page)
>>
>> "L.W.(Bill) Hughes III" wrote:
>> >
>> > Hi Denny,
>> > That's nearly impossible to freeze a piston and not have it drag
>> > and burn: http://www.billhughes.com/WJCaliber.jpg Take her in as see
>> > what a mechanic says.
>> > God Bless America, Bill O|||||||O
>> > http://www.billhughes.com/
>> >
>> > D wrote:
>> > >
>> > > Hi Bill,
>> > > No, no the actual brake rotor/disc itself is what I'm talking about.
> It
>> > > shows little or no wear. Mine is not evenly shiny where the pad
> contacts it
>> > > as the one is in the picture you sent.
>> > > Thanks.
>> > > Denny
>
>