death wobble - '04 TJ

I drove a CJ as my daily driver until this past December when I traded for a
2004 TJ with the 4.0L and small 225 x 70 R15 tires (I will fix that later).
It had only 13k miles when i got it, but it is past the 36 month warranty
period. It has driven beautifully until last night. At 47-48 mph, it
started a shimmy up front. If I maintained throttle pressue, the shimmy
progressed to a full bore death wobble...you could see the front end shake
violently and the steering wheel was hard to hold. When I slowed down below
40mph, it would go away. I stopped and walked around, but could not see
anything wrong. I dropped my son off at his baseball practiced and went
back out....same thing. I stopped to turn around after a couple of miles,
on a hill, and as i sat there with the clutch in, i noticed that the jeep
was not rolling back even with out the brake on....like the e-brake was
partially engaged (it wasn't, I checked). When i got back to the ballpark,
I did another turn around the jeep and noticed a significant amount of heat
coming off of the front passenger wheel. You could smell it and see a small
amount of smoke coming off of the brake pad.....so i am assuming that the
caliper stuck for some reason. Practice lasted another hour, and when I
drove home.....it drove perfectly. Again this morning it drove great on the
way to work. Any ideas? What would cause the caliper to stick just that
one time?

"Crushed Red Pepper" <bdickerson (AT) chartwellhospitality (DOT) com> wrote

I drove a CJ as my daily driver until this past December when I traded for
a 2004 TJ with the 4.0L and small 225 x 70 R15 tires (I will fix that
later). It had only 13k miles when i got it, but it is past the 36 month
warranty period. It has driven beautifully until last night. At 47-48
mph, it started a shimmy up front. If I maintained throttle pressue, the
shimmy progressed to a full bore death wobble...you could see the front end
shake violently and the steering wheel was hard to hold. When I slowed
down below 40mph, it would go away. I stopped and walked around, but could
not see anything wrong. I dropped my son off at his baseball practiced and
went back out....same thing. I stopped to turn around after a couple of
miles, on a hill, and as i sat there with the clutch in, i noticed that the
jeep was not rolling back even with out the brake on....like the e-brake
was partially engaged (it wasn't, I checked). When i got back to the
ballpark, I did another turn around the jeep and noticed a significant
amount of heat coming off of the front passenger wheel. You could smell it
and see a small amount of smoke coming off of the brake pad.....so i am
assuming that the caliper stuck for some reason. Practice lasted another
hour, and when I drove home.....it drove perfectly. Again this morning it
drove great on the way to work. Any ideas? What would cause the caliper
to stick just that one time?

It could be one of a couple of things:

Most likely, the caliper sliders got stuck and eventually freed up. If that
is the case, cleaning and lubing the caliper sliders will remedy this.

....or, the caliper itself was stuck, and you will see more of it to come, a
rebuild of it is possible, but replacing the caliper is cheaper.

....or, the brake hose is bad, limiting the return flow of fluid from the
caliper, back to the master cylinder.

Usually, it occurs in that order.
Start with the cheap fixes first, and do both sides.

Spdloader

On Tue, 15 May 2007 12:19:13 -0500, "Crushed Red Pepper"
<bdickerson (AT) chartwellhospitality (DOT) com> wrote:

Any ideas? What would cause the caliper to stick just that
one time?

I would be concerned that the reason that it stopped might be that the
brake pad had worn away or the brake disc was ruined...

I checked last night....plenty of pad left.
"Grumman-581" <grumman581 (AT) DIE-SPAMMER-SCUM-gmail (DOT) com> wrote

On Tue, 15 May 2007 12:19:13 -0500, "Crushed Red Pepper"
bdickerson (AT) chartwellhospitality (DOT) com> wrote:
Any ideas? What would cause the caliper to stick just that
one time?

I would be concerned that the reason that it stopped might be that the
brake pad had worn away or the brake disc was ruined...

I'd start with looking at the caliper slider pins. They should be clean
and shiney, use the special high temp/high tac lube on them. And they
will stick and unstick for the first few times, sooner or later they
will stick long enough to fry everything.

The high caliper/rotor temp did not do anything good for the brake
parts. You checked the pad, did you ckeck both pads (inner and outer)?
Rotor ok (not scored or warped)? Bleeding the brakes wouldn't hurt, gets
the cooked brake fluid out of the caliper.

Crushed Red Pepper wrote:

I drove a CJ as my daily driver until this past December when I traded for a
2004 TJ with the 4.0L and small 225 x 70 R15 tires (I will fix that later).
It had only 13k miles when i got it, but it is past the 36 month warranty
period. It has driven beautifully until last night. At 47-48 mph, it
started a shimmy up front. If I maintained throttle pressue, the shimmy
progressed to a full bore death wobble...you could see the front end shake
violently and the steering wheel was hard to hold. When I slowed down below
40mph, it would go away. I stopped and walked around, but could not see
anything wrong. I dropped my son off at his baseball practiced and went
back out....same thing. I stopped to turn around after a couple of miles,
on a hill, and as i sat there with the clutch in, i noticed that the jeep
was not rolling back even with out the brake on....like the e-brake was
partially engaged (it wasn't, I checked). When i got back to the ballpark,
I did another turn around the jeep and noticed a significant amount of heat
coming off of the front passenger wheel. You could smell it and see a small
amount of smoke coming off of the brake pad.....so i am assuming that the
caliper stuck for some reason. Practice lasted another hour, and when I
drove home.....it drove perfectly. Again this morning it drove great on the
way to work. Any ideas? What would cause the caliper to stick just that
one time?

In article <134jqqb4c2b5r15 (AT) corp (DOT) supernews.com>,
Crushed Red Pepper <bdickerson (AT) chartwellhospitality (DOT) com> wrote:
#I drove a CJ as my daily driver until this past December when I traded for a
#2004 TJ with the 4.0L and small 225 x 70 R15 tires (I will fix that later).
#It had only 13k miles when i got it, but it is past the 36 month warranty
#period. It has driven beautifully until last night. At 47-48 mph, it
#started a shimmy up front. If I maintained throttle pressue, the shimmy
#progressed to a full bore death wobble...you could see the front end shake
#violently and the steering wheel was hard to hold. When I slowed down below
#40mph, it would go away. I stopped and walked around, but could not see
#anything wrong. I dropped my son off at his baseball practiced and went
#back out....same thing. I stopped to turn around after a couple of miles,
#on a hill, and as i sat there with the clutch in, i noticed that the jeep
#was not rolling back even with out the brake on....like the e-brake was
#partially engaged (it wasn't, I checked). When i got back to the ballpark,
#I did another turn around the jeep and noticed a significant amount of heat
#coming off of the front passenger wheel. You could smell it and see a small
#amount of smoke coming off of the brake pad.....so i am assuming that the
#caliper stuck for some reason. Practice lasted another hour, and when I
#drove home.....it drove perfectly. Again this morning it drove great on the
#way to work. Any ideas? What would cause the caliper to stick just that
#one time?
#

Did you upgrade your 7/70 Powertrain warranty to Maximum Care within
48 months and 48000 miles?

If so, your covered. Go take it in and pay your deductable.

I snuck in with 47850 on my wife's (new to us) '04 WJ. Considering
the issues we had with the bleeding-edge year '99 WJ, I'm glad we got
it. I'll do the same with the '04 Rubi when it hits the 3/36 mark as
well.

/herb