The mystery "failure"

[OVERKILL]

I had a similar parking brake issue with my WK. Intermittent vibration; hot brake on one rear wheel. Happened once every few months. Caliper not sticking. What I found was rust flaking off the 14 year old parking brake shoes jammed the actuator. New shoes/springs hardware fixed it. But your issue is on the front. I’m wondering if the caliper mount is loose or the caliper itself is slightly loose. Caliper bushings? What about those nuts that hold the rotor to the hub?

These are fixed callipers, so there's no bushing or slide. Calliper seems firm, and it's fine now I could put a wrench on it I suppose, but I'd have to pull the wheel.

These are two piece rotors, so yeah, there are a pile of what appear to be 10mm nuts that hold the disc to the hat. They all look tight, no idea what torque they are supposed to be at , but I'd think if they were loose it would be somewhat obvious.

 

[dishdude]

. Wow!

Right? You know how many beater Corollas he could buy for that?

 

[Delta]

Right? You know how many beater Corollas he could buy for that?

In my area? None...

 

[mrbreezeet1]

Strange. Last year I had a sort of similar issue on one of our vehicles. In our case, I KNEW it was brake-related because not only was one wheel getting hot but you could also smell hot brakes, car would lug when accelerating, pull under braking, etc. It would also make a washboard-esque noise occasionally, more of a cyclical humming at speed. I thought it was a sticking caliper but it was actually a collapsed brake line in the front (the flexible portion). I only found this out because I replaced the caliper to no avail. The brake line had no visible damage, but I'm guessing that internally it was collapsing when the brake pedal disengaged and the master cylinder went to draw back the fluid in the lines. I replaced it and all is well.

If you run into this again, jack up the offending wheel, when it is stuck, and try to turn the wheel. Crack the bleeder valve.
If it instantly frees up, it points to the hose. If it does not free up, it points to the caliper.

 

[mrbreezeet1]

I was thinking maybe it was possible that something jammed between the calliper and pad?

Would be weird for it to only affect the one wheel though, and no indication that the ESC or TC were engaging, and I was able to hit the gas and accelerate hard and the vibration persisted.

What's interesting is that this didn't occur after a brake application. I had been driving for like 15km at around 90-ish km/h (~55mph) when it started happening out of the blue.

Yeah, Hung caliper, be it a hose or the piston itself, can give a bad vibration. Happened to my little 94 ford escort. Did it the whole way to work.
I jacked it up, cracked the bleeder, it was still hung up. Rebuilt the caliper, and all was well.

 

[SammyChevelleTypeS3]

These are fixed callipers, so there's no bushing or slide. Calliper seems firm, and it's fine now I could put a wrench on it I suppose, but I'd have to pull the wheel.

These are two piece rotors, so yeah, there are a pile of what appear to be 10mm nuts that hold the disc to the hat. They all look tight, no idea what torque they are supposed to be at , but I'd think if they were loose it would be somewhat obvious.

Surprised Jeep dealer did not offer any thoughts / possibilities. Did they ask if you narrowed it down in anyway to one area? Front / rear / driver or passenger side of vehicle? Questions that might help you figure it out:

1) How fast ? what speed did it occur at?
2) Did it happen at more than one speed?
3) Did it occur when breaking or cruising? or both?
4) Did you feel it only in the steering wheel? or the body/frame/ or brake pedal?
5) Were you using cruise control at the time?
6) Transmission in OD? or nor?
7) Has this vehicle ever felt like transmission was slipping in past or this time?
8) Has vehicle ever had any suspension work done? Recently? Any type of repairs?
9) Has there been any noticable strange steering issues?
Jeep has reported some known shudder / steering in some 2020 / 2021 models.
10) Wild goose hunt now: Have the tires recently been aired up?
Are all the tire psi at normal, same as always?
Tires recently fooled with in any way? Rotated? Balanced? Repaired? This has been experienced
in vehicles with lose lug nuts on a wheel before is reason for asking.

 

[AmBeRnEcTaR]

Yeah, as far as I know. Things aren't super accessible because of the fixed nature of the callipers. Brake pedal felt fine.

I have the vehicle now and it feels fine. Both callipers feel the same temperature, as do both rotors after lots of stopping. No smell, no vibration. Guess we'll see if it comes back?

TPS?

 

[SammyChevelleTypeS3]

No risk of it being the parking brake here, since it was a front brake. Looks like this:

View attachment 141514

Here's what the pads currently look like:
View attachment 141516

That all looks perfect and even the pad looks like it is fine as well. Unless there is something off kilter in the caliper you can not see with it installed that can move at times.

 

[HoosierJeeper]

Had this happen on my 05 Liberty - felt like I was hitting rumble strips. Bad caliper on the rear. So I'd lean towards a caliper issue. Whenever I've gotten a rock stuck somewhere in the brakes (happens a lot off road!), it's always a screeching noise.

 

[2EHA]

just brembo being brembo and seizing a piston or two at low miles.

a tale old as time itself

 

[MrJayhawk]

Just for grins, I wonder since everything mechanical is checking out ok it would be worthy to replicate the trip and see if it might have been the road surface possibly?

 

[ARCOgraphite]

"Customer states ...Could not duplicate... " story of my dealership experience anywhere always.

I had a front suspension part falling off (LCA) on a 2004 Suzuki Aerio SX. After two visits, I finally convinced the Service manager after a ridealong to have his crew repair it under warranty. He was a nice guy, otoh the service writers must all be trained to deflect. I had some new old stock Pierre Cardin dress shirts from the 70's still packaged - I gave him one since he was a sharp dresser. I think that tipped the scales in my favour.
Surprising transactional experience. -Ken

 

[Thermo1223]

Yeah, unless maybe it was a chunk of rubber or something? It didn't FEEL like the brake was dragging, which I would have expected it to if it was bad enough to cause this issue. I could be wrong though.

A Civic with 4 locked wheels could be chained behind the Jeep and you wouldn't feel that either with that much motor.

 

[OVERKILL]

Surprised Jeep dealer did not offer any thoughts / possibilities. Did they ask if you narrowed it down in anyway to one area? Front / rear / driver or passenger side of vehicle? Questions that might help you figure it out:

1) How fast ? what speed did it occur at?

Around 55mph (~90-95km/h)

2) Did it happen at more than one speed?

The issue persisted when I accelerated, and let off the gas (sped up, slowed down). The frequency followed the speed. When I got really slow it was like "thud thud thud"

3) Did it occur when breaking or cruising? or both?

Cruising. Had been going along at this speed for about 15km.

4) Did you feel it only in the steering wheel? or the body/frame/ or brake pedal?

Steering wheel and whole vehicle. Did not feel it in the brake pedal when I hit the brake.

5) Were you using cruise control at the time?

No.

6) Transmission in OD? or nor?

Yes, it would have been in 8th.

7) Has this vehicle ever felt like transmission was slipping in past or this time?

No

8) Has vehicle ever had any suspension work done? Recently? Any type of repairs?

No

9) Has there been any noticable strange steering issues?

No

Jeep has reported some known shudder / steering in some 2020 / 2021 models.
10) Wild goose hunt now: Have the tires recently been aired up?
Are all the tire psi at normal, same as always?
Tires recently fooled with in any way? Rotated? Balanced? Repaired? This has been experienced
in vehicles with lose lug nuts on a wheel before is reason for asking.

Tires are quite new, Michelin X-ice Snows, put on for this winter. I installed them, in the driveway, torqued the wheels, then re-torqued them after 200km. I have TPMS sensors in the winter wheels, all are at the proper pressure.

Issue has not returned since happening.

 

[SammyChevelleTypeS3]

Unless you have already narrowed your issue down to one wheel on the vehicle in some way.... ?
Gut instinct tells me short of some plastic, rubber or cardboard debris that affected the brakes without damaging rotors or pads that the shuddering is transmission or electronics related. If it were tires, suspension or brakes, it seems it would have likely repeated itself already with each drive. Dealership Techs would have found it easily as well. These people found nothing but offered you a $3000 brake job? Interesting. Loose lug nuts can do similar with one difference. You can almost always replicate the shudder each time you get to that certain speed. Yours will not. Transmision or electronics?

Around 55mph (~90-95km/h)

The issue persisted when I accelerated, and let off the gas (sped up, slowed down). The frequency followed the speed. When I got really slow it was like "thud thud thud"

Cruising. Had been going along at this speed for about 15km.

Steering wheel and whole vehicle. Did not feel it in the brake pedal when I hit the brake.

No.

Yes, it would have been in 8th.

No

No

No

Tires are quite new, Michelin X-ice Snows, put on for this winter. I installed them, in the driveway, torqued the wheels, then re-torqued them after 200km. I have TPMS sensors in the winter wheels, all are at the proper pressure.

Issue has not returned since happening.

Sounds like you checked and looked at everything all us non pros would know to do. At least now you know that everthing short of electrical or the trans are in tip top shape. STUFF Happens? Hope not again.

 

[OVERKILL]

Unless you have already narrowed your issue down to one wheel on the vehicle in some way.... ?

It was the left front wheel that smelled hot and where the vibration seemed to be coming from. It is not doing this now though.

 

[Deleted member 89374]

And that's the thing, there was not a massive amount of heat coming from the rotor, and the calliper itself was not hot, but something smelled very hot.

If it was mine, I would drain and fill the front differential. If a lot of debris and/or sediment comes out, that's where your issue comes from.

This is what came out of my noisy front diff when I drained it the second time (had Red Line 75W-90) and switched to HPL Differential Life 75W-90. The good news is that the noise is gone and it operates normally now.

(Don't mind the little piece of leaf-debris to the left, the wind blew it in when I had the container on the ground.)

 

[OVERKILL]

If it was mine, I would drain and fill the front differential. If a lot of debris and/or sediment comes out, that's where your issue comes from.

This is what came out of my noisy front diff when I drained it the second time (had Red Line 75W-90) and switched to HPL Differential Life 75W-90. The good news is that the noise is gone and it operates normally now.

(Don't mind the little piece of leaf-debris to the left, the wind blew it in when I had the container on the ground.)

Planning on changing it at 50,000km.

 

[Deleted member 89374]

Planning on changing it at 50,000km.

How far are you from reaching 50K?

 

[OVERKILL]

How far are you from reaching 50K?

About halfway there.