lol ya i need haynes

 

LOL, No crap bud, It's very easy to adjust them. Now put some more damn info about your truck in your sig!

 

Slotted rotors have one purpose and one purpose only: To vent gas. Under extreme braking, the trapped air and gaseous decomposition products of the pads expand due to heat, and reduces braking efficiency by pushing the pads away from the rotors -- a lot like hydroplaning tires on wet roads. The slots let the pressure out and allow the pads to remain in contact with the rotors. Although greater wear on the leading edges of the pads is normal, if it's really very pronounced it's due to this gassing holding the trailing edges away from the rotors.

Drilled solid rotors have one purpose: To reduce weight. A drilled solid rotor does not vent gas because there's another pad on the other side blocking air flow through the holes. A drilled vented rotor will reduce weight and provide some (minimal) gas pressure relief, but only until you pack the holes with brake dust. Then that brake dust acts like an insulating blanket and traps the heat, and you get stress cracks like in the photos ahead of me in this thread. If you drill a stock (vented) rotor, you're not leaving enough material behind to dissipate heat, and making the heating/cracking problem worse.

The best advice you'll ever get about drilled rotors: Don't.

If you're often running heavily loaded or live in the mountains, go with slotted rotors. If heat is still a problem, throw on some ducts after finding a good location for the intakes -- but remember to plug them up tight when it rains because the steam pressure you'll build up may well be enough to overwhelm your slotted rotors.

ABS doesn't affect the self-adjusters at all. If you don't do much backing with firm application of the brakes at the end, your self adjusters aren't even being actuated. If you do quite a bit of that (as when plowing in a hurry), it could be worn teeth on the self-adjusters, worn actuators, or a need for lubrication of the self-adjusters. Lack of lubrication is usually obvious because you'll have wear on the actuator arm and the teeth of the adjuster wheel. If I had the problem you've got, I'd replace those parts anyway, and use copper anti-seize on the threads because it won't melt and run out to contaminate the drums.

I don't do much backing, so every now and then I get out of town where I don't have to worry about other vehicles showing up unexpectedly and do several (10 or 20) backing runs with hard application of brakes at the end. It's less of a PITA than crawling under the truck to adjust the brakes.

 

Unreg, you're going to take this as me being a smartarse, but I ask you not to- it's not at all where I'm coming from. I would just like to hear what you say about this because you're obviously pretty smart about this stuff..

Don't pads have that recess in them specifically to stop what you're describing? And I've heard of the phenom before, but I was told it is a large consideration for things like heavy truckers descending mountain and such- and not much of a concern for light trucks/passenger vehicles- plus, w/ ABS equipped on most cars the situation is totally resolved. (I hate ABS by the way, it simply try's to correct lack of driver ability- and you can't threshold brake with them)..

I drive a '02, w/four wheel disc.. I hang out here as opposed to the 3rd gen because you guys are much more in tune to the 5.9Mag that I run also.. I'm MUCH happier with the disc's... I had a '95 which was seriously hampered by those dang drums when towing decent weight in the mountains.

 

I wouldn't have taken it that way even without the preface. No worries here -- I'm an engineer and expect to be challenged.

Some do. Others don't. In most cases those cuts are for noise reduction rather than gas venting.

With a slotted rotor, every square millimeter of the friction material sees the passage of a gas venting slot every so often. With pseudo-equivalent slots cut into the friction material, none of the material that should be in contact with the rotor ever sees a gas vent. The pad must be pushed away from the rotor by gas pressure in order for that gas to escape via the cuts in the friction material. So braking is somewhat improved because the pads stay closer to the rotor, but it is still suboptimal because there's still gas between the surfaces.

If you've got slotted rotors you're better off with plain, smooth surfaces on your pads.

A light truck/passenger vehicle can see demanding braking applications if the driver chooses to make them happen. Drag a heavy trailer and find a long downgrade, bingo, you've got a demanding braking application. Get cruising along at 75MPH on the interstate and find a reason to bring the vehicle to a stop in a hurry but short of activating the ABS, you've got another. Stop a heavy trailer from highway speed you've got another.

Speaking of which: most RV/utility trailer brakes are truly inadequate. The drums are usually too thin and lacking cooling vanes, so they fade very quickly. In a long firm braking situation you can often feel the weight transfer to the tow vehicle when the trailer brakes fade... I hate that. My trailers always got upgraded with thicker, vaned ("finned") drums.

ABS isn't intended to solve the gassing problem. ABS only comes into play when a wheel is at or very near lock-up (depending upon how it's implemented), so it doesn't do anything when you're applying steady but not extreme pressure to the system. At anything short of near-lock, ABS doesn't back off the system pressure so the gas isn't given anywhere to go except between the friction material and the rotating mass where you do not want it to be.

Four-wheel disc brakes kick serious ***. Especially for towing. The big benefit is that discs run cooler and cool faster once heated due to their open design, so they don't gas and glaze as soon as drum brakes dissipating the same energy.

 

see- I dig it.. I learn something new everyday! You're absolutely making sense- the channel in the braking surface would expel the gasses, the channel in the medium would really do nothing but take away valuable pad footprint on the braking surface.. That should have been obvious to me but it wasn't until you said so..

I used to have a 26' travel trailer.. and went overboard with the braking system on that thing- why asks you? I had to 'outrun' it coming off a mountain once.. When I got to the bottom and relaxed a little, I swore I would NEVER experience that again... It IS NOT a good feeling. The trailer had electric brakes w/ that pulse crap, and I was using an 'el cheapo' brake controller as well.

Folks make these trucks faster and faster- and that is fun... the more important thing though, is getting them to stop equally well..

 

Many, many things are obvious only in retrospect.

I can relate. I won't pull someone else's trailer for that very reason. I'm the guy whose tow vehicle's brake controller sits on top of the dash within easy reach so I can assist fading brakes just long enough to pull over and allow them to cool.

I raised my kids to understand that a car that won't go is a nuisance, but one that won't stop is a deathtrap. The one time my eldest daughter thought she'd go with cheap tires she had a learning experience (the interstate gets very hot in Arizona) followed by new tires all around on both her car and her husband's. Next time one of her friends or a salesdroid tells her that the no-name cheapies are perfectly fine, I hope I'm far away so I don't get any blood spatter on me.

 

Slotted rotors let me stop about 3 - 4 cars shorter with my oversize tires my rotors were getting supper hot trying to stop my truck switched have not had a problem sense.

 

man, all this GREAT info about brakes, and no one will ever be able to find it because lastrights spelled the damned title wrong

 

Looks like No Child Left Behind ain't working like it was supposed to.