First, Happy holidays to everyone. Hope you all enjoy a healthy Thanksgiving...
About 20k miles ago I changed my front brake pads to Akebono pro act ceramic pads (stock rotors) Now, about 10k miles ago I changed my rear pads to akebono pro act ceramic. (stock rotors)Now, it feels like my rear rotors are warped, b/c when I drive the car on the highway and hit the brakes the whole car starts to shake, It looks like I need new rotors on the rear. My car only has 54k! Is this normal? The shke recently developed (within the last 2-3 weeks) Now the shop tells me that I cannot change the rotors without changing the pads, otherwise they will squeekand not make good contact, b/c the pads have accustomed themselves to the rotor. The dealer says I should put back all OEM, but thats expensive! I am not willing to perform the brakes myself. Whats the truth on this subject? Thanks people

 

The mechanic is right, thats the "safe way to go" but if you were to put new rotors on and leave the pads you have, after a few hundred miles they should break into those new rotors. as far as the noises you will get from doing it that way, im not too sure. I don't think that a mechanic would want to do the job and leave the old pads in. As far as going all OEM, of course they want you to do it that way so they can ream you. don't go with the dealer, go to a private mechanic. Doing brakes is rocket science, once you do them once you can do them on anything. Do yourself a favor an spend the extra sixty bucks on new pads so you don't have anymore problems.

 

now, do you think that rear pads after 10K have something to do with the warped rotors? It just makes me upset that rotors are warped 6 months after. how long do rotors last on average? The akebono are supposed to be some good pads...Thanks

 

Im not positive about how long, but usually when you do brake pads you get your rotors shaved so they are a smooth surface again, after a few brake jobs you will loose some of that meat on the rotor. i deff dont think that you should need new rotors with 60k, not positive tho. The pads might not have been set right or you e-brake could have been dragging on the rotor. if it heats the rotors to a point they will warp.

 

doing brakes is not hard at all. buy a haynes manual it has pics and step by step instructions. you can do this!!!!

 

at the shop that i work at we have ran into this problem, i guessing since you did change your brakes yourself you probably didn't turn the rotors so the rotor were probably warp a lil already. if i were you i would go to another shop to have them mic your rotor to see if they can turn them. as far as your brake pads, i myself wouldn't change them i would reuse them and after sometime they will wear themselves in.

 

I would not worry about the rear brake pads as much as if they were front pads...

Get some rotors and use the old pads... sand them down a little and they will wear into place on their own. Remember the rear only does about 30% of all braking so they havent been worn down THAT much yet.

 

A haynes manual is by the far the best investment anyone can make.

 

What does mic mean? And if they were wapred a little already, wouldnt I have felt it right away and not 10k later? I feel like that maybe its the mechanics faul-maybe he didnt set the rear pads correctly and now I have to get new rotors- thats not cool. and how much should i be paying for cut rotors, and how much for new ones respectively? Thanks

 

mic = to measure with a micrometer, to make sure the rotors are thick enough.

 

I'm new to this forum but not new cars in general (have owned 14 different makes and put about 1.5 million miles total on those I've owned) or to Maximas (got about 35 years experience and currently own 3 Maximas (a 93 with 198,000, a 97 with 68,000 and a 98 with 56,000). As some posters have already said, brakes are not rocket science but there are some tricks. First of all, when you change pads, don't turn the rotors unless you absolutely have to (deep scoring or major warp). The earlier you get the rotors machined, the quicker they will warp, machining the rotors also reduces the amount of steel available to absorb heat, and if they turn the rotor to remove warp, the resulting thickness of the steel varies, causing heat stress to warp them earlier. Be careful to unload some brake fluid from the reservoir before you push your puc back into the caliper, that stuff takes paint off and makes a big mess.

New pads will wear in to match the rotors in no time. Don't try to accelerate this process though by doing a series of hard stops, the lines of contact where the smooth pads are wearing down to match the scored rotor will get really hot, and can glaze those areas on the pads, plus this technique will cause a lot of heat buildup in the rotor which leads to warp. Just use light to moderate pressure to stop for the first 20 to 30 stops, and leave plenty of time between stops to allow things to cool.

Always, always, always torque your lug nuts yourself. Use a torque wrench, and a cross star pattern (1,3,5,2,4,) to ensure the wheel is snugged down on the rotor evenly. I torque them all down to 80 ftlb and then to final torque, at the bottom end of the approved torque range. Even if the garage uses a torque wrench and you watch them do it, check the torques yourself. Then check them again about 1000 miles later. Alloy wheels tend to loosen otherwise. You can even straighten out a warpped rotor this way, if you catch it before it is permanently warpped.

Lots of hard stops with improperly torqued lug nuts will warp even the best rotors. With care in torquing lug nuts and light stopping when possible, I get about 45,000 - 55,000 on front pads, and about 120,000 miles on rotors before they begin to warp and get obnoxious. (On two of my Maximas I have yet to replace the rear pads.) Then, I just replace the rotors with new heavy duty rotors. I learned early that truing rotors by machining is a waste of money. Just some food for thought.

 

So what is the final lbs/tq? 80 something? I would consider gettting a torque wrench if it could maybe save my rotors... By the way, welcome to the org

 

72-87 ft/lbs.

definitely buy a torque wrench, you need it for a lot of things.

 

ya know something? I'm visiting family and I'm a few thousand miles from my max right now, but i'm thinking about it and I am starting to get pissed off. Im starting to think that the reason why my rotors are starting to warp is due to some error that the mechanic did with my brakes, maybe the pads are not on correctly or what not.When I first got the job done it stopped like a dream. The wheels spin freely, I played with them when i was getting my tires balanced last week. Anyway, I think he messed something up, but how can i prove it? I mean it's 10k later. wouldnt an error cause damage or show itself before 10K? By the way, they have also started to squeek. I hate having to shell out money for things like this BS. what rebutals do I have for him? I dont want to go in there and look like an *** and burn bridges, but I dont want to shell out money for somebodys lousy workmanship .

 

I've heard rumors that unevenly and overtorqued lug nuts can cause rotors to warp. Which is why I also do the exact same thing - torque wrench, 80ft-lb. Shop around - a cheap clicker-type wrench is only $30 sometimes. (Also get a 21mm or 13/16" socket, and you're done).

Regarding rotor replacement, during a pad change, there are 3 options.
1) new pads only, leave rotors (only works if the original rotors are very smooth and straight)
2) new pads, turn rotors (had disadvantages nicely described by Accordman above)
3) new pads, new rotors (and new brake hardware kit - shims and springs)

I opt for #3 whenever possible, but only because I do brakes myself. I just buy the nearest to OEM Brembo rotors, and they work pretty well. There are plenty of sources out there showing how to change brake pads and rotors, so the only tips I have to add are: use lots of brake cleaner, sand off any corrosion on the hub before putting on new rotor, and use copper anti-seize on the lug studs when you're done.

 

Okay guys, being that its only been shaking for about 2 weeks, maybe I can save the rotors. When I get home I am going to buy a torque wrench and make sure that all my lug nuts are equally torqued to 80lbs. Maybe this will be enough to remedy the warpage and correct it. I mean, it still may be possible to correct the warpage right? It's not like I have been driving for 5k on warped rotors. Its worth a try at 30 bucks for the torque wrench.....

 

Just having the torque wrench is worth it. At least then you can always keep them torqued properly. (Most service places will overtorque no matter what you request). Even if you never use it, the one day you need to change to the spare tire you'll thank the heavens you've got something bigger than the spare wrench to do the job.

Dave

 

a torgue wrench is definitly worth it.....if your redoing your heads. dont waste time with torguing down your lugs. just tighten the **** out of um. if the car only shakes when braking its not your wheels. if the rotors are warped, there garbage. can't shave something bent, by the time you get it true again youll need new rotors anyway

 

If you have time, indexing the rotors really works. I was able to bring the rotors runout back to specs and eliminate brake vibration without the need to turn the rotors.

 

I guess it's obvious that this guy is an idiot.

Dave

 

sorry to steal the thread, but i got a problem with my brakes that might be fixed by tightening my lugs. You tell me: When braking and aproaching a full stop, rubbing noise, almost like wheel rub.
I had my brakes done and I discovered today about 500 miles later that he forgot to put the cap back onto the brake fluid reservoir. Is this bad?
I put the cap back on and this is when I started to get the rubbing noise; even under moderate braking pressure.

 

Is the fluid still filled to the proper level? Is it spilled anywhere (clean it up, hurry before it eats any paint it touches!!). If you don't have the cap, I'm not sure I recommend driving it.

If the fluid level is too low, you probably need the entire system bled, and since it would have admitted air at the reservoir, it will take a fair amount of fluid. Yes, it's a human mistake, but be sure that this garage knows their grease pit from their ***.

 

I have the cap and i put it back on. there was no leaks as much as i could see. Fluid is at max. Would air still have gotten in? I just got new rotors, pads, and flush done all at once.

 

It's not likely that you got air in the system providing the fluid is up to normal level. Besides, the symptoms of air in the brake lines is a spongy pedal and poor braking action.

I believe there is a plastic screen in the top of the reservoir. Clean the rim of the reservoir with a towel and carefully lift the screen out. Inspect it for contaminants, dirt, stuff. Blow the screen clean with an air hose. Replace the screen and recap. Don't let any crap get into the reservoir, it will ruin your master cylinder seals. As far as the noise, did the guy who did the brake job do anything to adjust your emergency brake? I've heard rubbing noises from the e-brake if anything was not aligned properly when the rear rotors are put back on. And the rubbing noise doesn't necessarily start right away, it can take a few thousand miles to show up.

Back to brake rotor warp. I did a little research. I found (and I agree with the finding) that rotor warp isn't the whole problem with pulsing brakes. It just sets the brakes up for uneven wear which leads to thickness variation in the brake rotor, which in turn results in pedal pulse. You see, when you brake, the pads are pushed out against the rotor, but when you lift off the brake, the pads don't really retract, they skim the disc all the time. This skimming causes the brake rotor to wear. If the rotor is flat (less than 0.002" TIR) the wear is even. If the rotor is warped, the floating caliper slides back and forth to follow the warped rotor, but the pads run a little harder on the high spots. This wear is therefore concentrated in the high spots on the rotor face, as it wears it becomes thinner, so when you brake, the pads grab the thick spots. If you brake hard all the time, you may see a discoloration in the disc, you know, those shades of yellow, brown, and blue to purple that indicate high heat. If you see these colors in some areas around the rotor rim, and not in other areas, you can tell where the thick and thin spots are. Another cause of thickness variation is hard spots in the cast rotor. Cheap castings are notorious for hard and soft spots, which lead to uneven wear.

 

ME? Who are you talkin about?

 

As a matter of fact, the guy did say one of my rear calipers were frozen and he unfroze it and cleaned it for me. Would that be a suspect? I guess if u can forget to put the cap on, there's other things that may be overlooked? Also, the rubbing noise seems to come from the front driver side. it's weird because the rotor i previously had installed was warped and I had a simliar rubbing noise [defective rotor sent back of course]