Why do my brakes pulse again?

T

Ted S.

Guest

• Jul 25, 2003

• #1

I have a 1997 Jeep Cherokee Laredo 4x4 with 36,000 miles on it. I do mostly
"around home" driving (not really city or highway driving).

My question is why my brakes 'pulse' once again. When braking, it feels
like there are high and low spots on the discs. I had them ground once
which fixed the problem but it's back yet again. I'm very easy on the
brakes. Someone said they may warp when hot and hitting a puddle but that
doesn't sound reasonable.

Any ideas as to why this keeps happening would be great. Thanks.

 

D

DougW

Guest

• Jul 26, 2003

• #2

Ted S. wrote:
> I have a 1997 Jeep Cherokee Laredo 4x4 with 36,000 miles on it. I do mostly
> "around home" driving (not really city or highway driving).
>
> My question is why my brakes 'pulse' once again. When braking, it feels
> like there are high and low spots on the discs. I had them ground once
> which fixed the problem but it's back yet again. I'm very easy on the
> brakes. Someone said they may warp when hot and hitting a puddle but that
> doesn't sound reasonable.
>
> Any ideas as to why this keeps happening would be great. Thanks.

Time to replace the rotors. Once they have warped badly they will warp
again even if turned flat.

Actually you could probably replace the rotors and pads yourself
for less than what some places charge to turn them.

--
-- DougW -- 93 ZJ 4.0 http://members.cox.net/wilsond
HESCO Supercharger - 300W IASCA Stereo - Edelbrock IAS Shocks
Gibson Exhaust - rear DCpower - custom gauge install - Stillen Rotors

 

M

Matthew S. Whiting

Guest

• Jul 26, 2003

• #3

Ted S. wrote:
> I have a 1997 Jeep Cherokee Laredo 4x4 with 36,000 miles on it. I do mostly
> "around home" driving (not really city or highway driving).
>
> My question is why my brakes 'pulse' once again. When braking, it feels
> like there are high and low spots on the discs. I had them ground once
> which fixed the problem but it's back yet again. I'm very easy on the
> brakes. Someone said they may warp when hot and hitting a puddle but that
> doesn't sound reasonable.
>
> Any ideas as to why this keeps happening would be great. Thanks.
>
>

Several things can cause rotor warping or nonuniform thickness:

1. Overheating from severe use (long hills, towing, etc.)
2. Marginally designed rotors (most vehicles today unfortunately)
3. Overtorqued lug nuts
4. Rust from lack of use
5. Probably several more that I'm not aware of!

I think overtorqued lug nuts are one of the most preventable causes, at
least next to avoiding severe use. Rotors are more likely to warp a
second time after being turned. There is now less metal to absorb heat
and less metal to resist the stresses induced by the heat. I think on
most new cars and many trucks, it is a waste of time to turn the rotors.
Better to just replace them, and the cost delta isn't all that great
anyway.

Matt

 

L

Lon Stowell

Guest

• Jul 26, 2003

• #4

Ted S. wrote:

> I have a 1997 Jeep Cherokee Laredo 4x4 with 36,000 miles on it. I do mostly
> "around home" driving (not really city or highway driving).
>
> My question is why my brakes 'pulse' once again. When braking, it feels
> like there are high and low spots on the discs. I had them ground once
> which fixed the problem but it's back yet again. I'm very easy on the
> brakes. Someone said they may warp when hot and hitting a puddle but that
> doesn't sound reasonable.
>
> Any ideas as to why this keeps happening would be great. Thanks.

Prior to any of the events, had anyone rotated or removed and
replaced any tires? This can cause the rotors to warp. Once
that happens, just replace them with an aftermarket set of
your choice. Turning them takes away metal which make them
more susceptible to warping in the future.

 

P

Paul Cordes

Guest

• Jul 26, 2003

• #5

"Matthew S. Whiting" <[email protected]> wrote in message
news:[email protected]...
> Several things can cause rotor warping or nonuniform thickness:
>
> 1. Overheating from severe use (long hills, towing, etc.)
> 2. Marginally designed rotors (most vehicles today unfortunately)
> 3. Overtorqued lug nuts
> 4. Rust from lack of use
> 5. Probably several more that I'm not aware of!
>
> I think overtorqued lug nuts are one of the most preventable causes, at
> least next to avoiding severe use. Rotors are more likely to warp a
> second time after being turned. There is now less metal to absorb heat
> and less metal to resist the stresses induced by the heat. I think on
> most new cars and many trucks, it is a waste of time to turn the rotors.
> Better to just replace them, and the cost delta isn't all that great
> anyway.
>
> Matt
>

Yep, #3 is the one I'd bet on. Usually by over zealous use of the air
wrench by the place that rotates your tires.

PC

 

D

Desert YJ

Guest

• Jul 26, 2003

• #6

What does rotating tires have to do with warping rotors?

I think it's over tightened lugs.


"Lon Stowell" <[email protected]> wrote in message
news:[email protected]...
> Ted S. wrote:
>
> > I have a 1997 Jeep Cherokee Laredo 4x4 with 36,000 miles on it. I do
mostly
> > "around home" driving (not really city or highway driving).
> >
> > My question is why my brakes 'pulse' once again. When braking, it feels
> > like there are high and low spots on the discs. I had them ground once
> > which fixed the problem but it's back yet again. I'm very easy on the
> > brakes. Someone said they may warp when hot and hitting a puddle but
that
> > doesn't sound reasonable.
> >
> > Any ideas as to why this keeps happening would be great. Thanks.
>
> Prior to any of the events, had anyone rotated or removed and
> replaced any tires? This can cause the rotors to warp. Once
> that happens, just replace them with an aftermarket set of
> your choice. Turning them takes away metal which make them
> more susceptible to warping in the future.
>
>

 

C

Cyberbilly

Guest

• Jul 26, 2003

• #7

"Ted S." <[email protected]> wrote in message
news:[email protected]...
> I have a 1997 Jeep Cherokee Laredo 4x4 with 36,000 miles on it. I do
mostly
> "around home" driving (not really city or highway driving).
>
> My question is why my brakes 'pulse' once again. When braking, it feels
> like there are high and low spots on the discs. I had them ground once
> which fixed the problem but it's back yet again. I'm very easy on the
> brakes. Someone said they may warp when hot and hitting a puddle but that
> doesn't sound reasonable.
>

Having warped disk rotors ground, or "turned" is a good short-term fix. The
problem is, however, that the more they are turned, the thinner they become.
The thinner they become, the more susceptible they become to warpage. So it
is a vicious circle kind of thing.

You probably need to have the rotors replaced. But if they wore out at only
36K miles, something ain't right. Maybe they can be replaced under
warranty.

-Cyberbilly

 

J

Jason

Guest

• Jul 26, 2003

• #8

The simple answer is Chrysler rotors are JUNK. My '96 Stratus rotors were
doing the same thing at 15,000 miles. Chrysler replaced them, but said that
the warranty on "wear parts" was only 12,000 miles. I had the same problem
with them at around 25,000 miles. I replaced those with the cheap NAPA ones
in the green box and they were on the car until I traded it in at 186,000
miles. They were $16 each.

I bought a new Sebring convertible about three months ago. I have 9,000
miles on the car and the brakes are pulsating already. It has 4 wheel
disks, so I'm bringing it in next week to see what they are going to do
about it.


"Ted S." <[email protected]> wrote in message
news:[email protected]...
> I have a 1997 Jeep Cherokee Laredo 4x4 with 36,000 miles on it. I do
mostly
> "around home" driving (not really city or highway driving).
>
> My question is why my brakes 'pulse' once again. When braking, it feels
> like there are high and low spots on the discs. I had them ground once
> which fixed the problem but it's back yet again. I'm very easy on the
> brakes. Someone said they may warp when hot and hitting a puddle but that
> doesn't sound reasonable.
>
> Any ideas as to why this keeps happening would be great. Thanks.
>
>

 

L

Lon Stowell

Guest

• Jul 26, 2003

• #9

You have some way to rotate tires without taking the lug nuts
off and putting them back? Care to share?


Desert YJ wrote:

> What does rotating tires have to do with warping rotors?
>
> I think it's over tightened lugs.
>
>
> "Lon Stowell" <[email protected]> wrote in message
> news:[email protected]...
>> Ted S. wrote:
>>
>> > I have a 1997 Jeep Cherokee Laredo 4x4 with 36,000 miles on it. I do
> mostly
>> > "around home" driving (not really city or highway driving).
>> >
>> > My question is why my brakes 'pulse' once again. When braking, it feels
>> > like there are high and low spots on the discs. I had them ground once
>> > which fixed the problem but it's back yet again. I'm very easy on the
>> > brakes. Someone said they may warp when hot and hitting a puddle but
> that
>> > doesn't sound reasonable.
>> >
>> > Any ideas as to why this keeps happening would be great. Thanks.
>>
>> Prior to any of the events, had anyone rotated or removed and
>> replaced any tires? This can cause the rotors to warp. Once
>> that happens, just replace them with an aftermarket set of
>> your choice. Turning them takes away metal which make them
>> more susceptible to warping in the future.
>>
>>
>
>

 

M

mic canic

Guest

• Jul 27, 2003

• #10

the xj rotors are a composit metal and warp real easy once they have be
resurfaced
the rotors don't take well to heat up after that so i would recommend new ones

"Ted S." wrote:

> I have a 1997 Jeep Cherokee Laredo 4x4 with 36,000 miles on it. I do mostly
> "around home" driving (not really city or highway driving).
>
> My question is why my brakes 'pulse' once again. When braking, it feels
> like there are high and low spots on the discs. I had them ground once
> which fixed the problem but it's back yet again. I'm very easy on the
> brakes. Someone said they may warp when hot and hitting a puddle but that
> doesn't sound reasonable.
>
> Any ideas as to why this keeps happening would be great. Thanks.

 

D

Desert YJ

Guest

• Jul 27, 2003

• #11

Oh.


"Lon Stowell" <[email protected]> wrote in message
news:[email protected]...
> You have some way to rotate tires without taking the lug nuts
> off and putting them back? Care to share?
>
>
> Desert YJ wrote:
>
> > What does rotating tires have to do with warping rotors?
> >
> > I think it's over tightened lugs.
> >
> >
> > "Lon Stowell" <[email protected]> wrote in message
> > news:[email protected]...
> >> Ted S. wrote:
> >>
> >> > I have a 1997 Jeep Cherokee Laredo 4x4 with 36,000 miles on it. I do
> > mostly
> >> > "around home" driving (not really city or highway driving).
> >> >
> >> > My question is why my brakes 'pulse' once again. When braking, it
feels
> >> > like there are high and low spots on the discs. I had them ground
once
> >> > which fixed the problem but it's back yet again. I'm very easy on
the
> >> > brakes. Someone said they may warp when hot and hitting a puddle but
> > that
> >> > doesn't sound reasonable.
> >> >
> >> > Any ideas as to why this keeps happening would be great. Thanks.
> >>
> >> Prior to any of the events, had anyone rotated or removed and
> >> replaced any tires? This can cause the rotors to warp. Once
> >> that happens, just replace them with an aftermarket set of
> >> your choice. Turning them takes away metal which make them
> >> more susceptible to warping in the future.
> >>
> >>
> >
> >
>

 

M

Markeau

Guest

• Jul 27, 2003

• #12

Many have already suggested improperly torqued lug nuts. My previous
98 Z28, a model which was infamous for warped rotors, developed the
dreaded pulsing brake pedal/warped rotor syndrome. But one time after
having the tires rotated it completely went away. And tire rotation
prior to that was done by a meticulous high performance shop who
always said they torque properly by hand, so I can only assume even
they made a mistake.

"Ted S." <[email protected]> wrote in message
news:[email protected]
> I have a 1997 Jeep Cherokee Laredo 4x4 with 36,000 miles on it. I
do
> mostly "around home" driving (not really city or highway driving).
>
> My question is why my brakes 'pulse' once again. When braking, it
> feels like there are high and low spots on the discs. I had them
> ground once which fixed the problem but it's back yet again. I'm
> very easy on the brakes. Someone said they may warp when hot and
> hitting a puddle but that doesn't sound reasonable.
>
> Any ideas as to why this keeps happening would be great. Thanks.

 

M

mic canic

Guest

• Jul 28, 2003

• #13

hmm funny thing those rims are not suppose to rotated do to the rim off
set is different front to rear

Markeau wrote:

> Many have already suggested improperly torqued lug nuts. My previous
> 98 Z28, a model which was infamous for warped rotors, developed the
> dreaded pulsing brake pedal/warped rotor syndrome. But one time after
> having the tires rotated it completely went away. And tire rotation
> prior to that was done by a meticulous high performance shop who
> always said they torque properly by hand, so I can only assume even
> they made a mistake.
>
> "Ted S." <[email protected]> wrote in message
> news:[email protected]
> > I have a 1997 Jeep Cherokee Laredo 4x4 with 36,000 miles on it. I
> do
> > mostly "around home" driving (not really city or highway driving).
> >
> > My question is why my brakes 'pulse' once again. When braking, it
> > feels like there are high and low spots on the discs. I had them
> > ground once which fixed the problem but it's back yet again. I'm
> > very easy on the brakes. Someone said they may warp when hot and
> > hitting a puddle but that doesn't sound reasonable.
> >
> > Any ideas as to why this keeps happening would be great. Thanks.

 

M

Markeau

Guest

• Jul 29, 2003

• #14

wrong! not only are the stock (non-ss) z28 rims exactly the same, but
so were the ss zr1 style takeoffs i got from slp engineering.
http://www.slponline.com/view_product.asp?PARTNUMBER=80072

"mic canic" <[email protected]> wrote in message
news:[email protected]
> hmm funny thing those rims are not suppose to rotated do to the rim
> off set is different front to rear
>
> Markeau wrote:
>
>> Many have already suggested improperly torqued lug nuts. My
previous
>> 98 Z28, a model which was infamous for warped rotors, developed the
>> dreaded pulsing brake pedal/warped rotor syndrome. But one time
>> after having the tires rotated it completely went away. And tire
>> rotation prior to that was done by a meticulous high performance
>> shop who always said they torque properly by hand, so I can only
>> assume even they made a mistake.
>>
>> "Ted S." <[email protected]> wrote in message
>> news:[email protected]
>>> I have a 1997 Jeep Cherokee Laredo 4x4 with 36,000 miles on it. I
>>> do mostly "around home" driving (not really city or highway
>>> driving).
>>>
>>> My question is why my brakes 'pulse' once again. When braking, it
>>> feels like there are high and low spots on the discs. I had them
>>> ground once which fixed the problem but it's back yet again. I'm
>>> very easy on the brakes. Someone said they may warp when hot and
>>> hitting a puddle but that doesn't sound reasonable.
>>>
>>> Any ideas as to why this keeps happening would be great. Thanks.