Front brake rotors warped on 99XJ

[rebeljeeper01]

haven't had them on very long but ,about 3 months ago I put crossdrilled and slotted rotors on the wifes 98 with hawks carbon ferro pads and it stops better than it ever has hope it lasts!!

 

[Jackhill442]

Rotor warpage is caused by schwagg pads that can't stand the heat. When you slam on the brakes and then sit at a stop light, the rotors are so hot that the pads melt a spot on the rotor as your foot sits on the brake pedal to keep stopped at the light. A few ways to combat this are high quality brake pads, ceramic or not, and shift to neutral and put on the park brake after hard braking to stop for a light. Oh, and I just installed the power stop rotors from quadratec and Hawk ceramic pads. Yeah, its pricey, but you end up saving money because these rotors will last. Man it stops better than ever, so smooth, and the pads guarantee long life and almost no dust.

 

[MAP]

Maybe I'm older than I think but I don't know what schwagg means. The rotors and brakes in question were not exactly cheap... Raybestos rotors and Raybestos Quiet Stop ceramic pads.
Now they aren't as expensive as Power Slot rotors or those Hawk pads but they aren't cheap.
They lasted 60,000miles(2.5 years) worth of driving. 60-70% freeway, the rest street driving.
I guess I should be happy with the results for the money I spent.

The part about the brakes melting a spot on the rotors doesn't make sense to me. The rotor would act as a giant heat sink in that example. If the spot on the rotor was somehow isolated from the rest of the rotor, then it might be possible.

It would be nice to know how long the performance rotors and pads last.
I would imagine several people on this board have used these.

MAP

 

[RichP]

Maybe I'm older than I think but I don't know what schwagg means. The rotors and brakes in question were not exactly cheap... Raybestos rotors and Raybestos Quiet Stop ceramic pads.
Now they aren't as expensive as Power Slot rotors or those Hawk pads but they aren't cheap.
They lasted 60,000miles(2.5 years) worth of driving. 60-70% freeway, the rest street driving.
I guess I should be happy with the results for the money I spent.

The part about the brakes melting a spot on the rotors doesn't make sense to me. The rotor would act as a giant heat sink in that example. If the spot on the rotor was somehow isolated from the rest of the rotor, then it might be possible.

It would be nice to know how long the performance rotors and pads last.
I would imagine several people on this board have used these.

MAP

60% freeway driving in calif is far worse than 100% city driving in NYC, going from 0-60-0, 0-70-0, 0-60-0, 0-80-0 in less than a mile is brutal on brakes, especially when that 60/70/80-0 part has to be faster than the 0-60/70/80 part. The two worst places in the country to drive are calif freeways and anywher in and around boston.

 

[Jackhill442]

Yes, the rotor really is nothing but a giant heat sink. The spot that gets melted on to it causes that pulsation. It isn't the rotor itself getting warped like an old record in the sun. That is why turning them gets rid of it. The cheaper, or more worn out rotors are, the less powerful of a heat sink it is, and the heat melts the pad if the pad is low quality. It can happen to good pads too if your rear brakes are not doing their job. I got so fed up with it that I swapped to rear discs to better balance, and I not only got much improved braking, but the front and the rears last longer, and never warp. I could really write a book on this, but I think you'll get the point. Hope this helps.

 

[JeffsJeep04]

Nothing "melts". What is going on is that your rotor is heated. Metal expands when hot. When you sit at a stop (IE at the end of a downhill offramp) and hold your brakes on, the rotor cools, but it can't cool as quickly where the pads are grabbing it. This causes un-even cooling, leading to warpage. If you turn warped rotors, you get thin and thick spots, and the problem is back before the 2nd good stop. If you try and prevent it by throwing on the e-brake, you stand a good chance of egging out your drums (yeah, it works both ways).

 

[MAP]

60% freeway driving in calif is far worse than 100% city driving in NYC, going from 0-60-0, 0-70-0, 0-60-0, 0-80-0 in less than a mile is brutal on brakes, especially when that 60/70/80-0 part has to be faster than the 0-60/70/80 part. The two worst places in the country to drive are calif freeways and anywher in and around boston.

I agree this LA traffic can be bad. What you describe is exactly the kind of driving I experienced when I was going to school near LAX. Both the drive up to school and back was a real pain. My drive now is south and it is much nicer. There is congestion but I don't get all the stop and go unless there is an accident.

MAP

 

[DenLip]

In my opinion, the reason these rotors warp is because they get too hot and do not dissipate heat as well as they should.
The only solution would be for the rotor braking surface area to have been bigger/wider. I still believe these things were underdesigned and the fact that so many people here have had problems supports this.

Most modern cars have the same problem. Brakes are made smaller than they should be to reduce weight... and unsprung weight in particular.

A stock XJ only weighs something like 3300lbs. That's fairly light. But when you start adding aftermarket stuff... and substitute bigger tires (causing more braking force to be required)... they quickly become insufficient.

I've had a few sets of warped rotors on other cars (always in the scenario mentioned: nailing it down hard from high speed, then sitting). Never on my XJ (so far).

Den

 

[langer1]

I think also that ceramic pad's add to the problem, when run on rotors not made for them. In most cases ceramic pads are as hard as the rotors, so you can look forward to the expense of replaceing both at the same time.

 

[gw204]

I just called (the info. isn't in the catalog)Summit Racing and got prices and part number on their Extreme Performance cross-drilled rotors:

EP5115L (for left)
EP5115R (for right)

$51.95 each

Those are the numbers I was given for a '91 XJ 4x4, but I think it's the same for multiple years.

I was gonna try them, but Summit doesn't have them in stock and I need something fast. So, I'm getting the el cheapo rotors from NAPA and a set of Performance Friction pads.

 

[Thayer]

I got so fed up with it that I swapped to rear discs to better balance, and I not only got much improved braking, but the front and the rears last longer, and never warp.

Ditto that! I think the rear disc conversion was my best mod so far... I don't think any combo of super duper stock sized front rotors and pads could a rear disc conversion.

 

[montanaman]

Ok ... maybe I'm retarded, but here goes:

Isn't pretty normal for brakes to start pulsing after 60k miles?

And isn't that the result of slight rotor warpage, but not serious damage?

And isn't it ok to turn the rotors instead of replacing them?

I'm no expert, but that's what I always thought.