new rotors/pads, but pedal pulsation is back

Is he a Nissan dealer who installed factory rotors ? I haven't had much luck with aftermarket rotors on certain models. Perhaps they just turned the rotors ?

It was indeed an imports dealer, but I don't know think they have the expertise of a full-time Nissan dealership. The rotors are definitely new too. The brakes have gotten even shoddier now, as they have gotten significantly weaker. Basically over the last two weeks, the pedal has started to sink in further and it takes more pedal effort to stop the car. I know that they used an air gun to tighten the bolts, so they possibly torqued the bolts at different torque amounts. I am guessing that could be part of the issue, but with the brakes getting significantly weaker too, could the calipers be to blame?

- Thanks again for any advice.

I'm guessing they did two things wrong with the rotors.

- gave you aftermarket rotors. They are known to suck. That's my personal experience with both Chinese and US Made rotors on certain Nissan models. I've used them on some models and other cars without issues but Nissan's seem particularly sensitive.

- Did not torque the wheels with a torque wrench, based on what you said. This alone will warp the rotors, even if they are Nissan rotors.

They're not going to be happy when you tell them that they have to spend $80/rotor to fix this problem, but that's the solution.

As to the brakes getting weaker, that's a different problem. They have other issues besides the rotors.

Cheap rotors and probably even cheaper pads.

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So then if I had to take care of these issues in another shop, would turning the rotors and remounting them properly take care of the problem?

- ecxt

Turned cheap rotors are still going to be cheap rotors....

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What brand of rotors would you recommend then?

- ecxt

Is there any vibration while driving? I had a similar problem with my '93 PF XE. I noticed some vibration at highway speeds AND when I used the brakes at any speed. Turned out to be a defective tire (slipped a radial belt or something) New 31" Continentals took care of the problem. Something to consider before spending more money.

-Craig

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I am actually aware of that particular issue. A friend of mine had that hardcore, and changing the tires took care of that. My tires are in pretty good shape though, so I doubt they are it.

- ecxt

It might. Turned rotors tend to warp more easily because they are thinner. The problem is that rotors distort once heated. So while they might be in spec when cold, they will warp during highway use and give you the pulsation.

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I understand what you are saying, but I am not quite ready to drop money on new rotors *just* yet. How much do you think is a reasonable amount to pay to have the rotors properly remounted, resurfaced, brake lines changed (to steel-braided, parts provided), and the brake system bled?

I *do* want to do this myself, but unfortunately I am away for the summer, and have access to no tools or a place to work. :(

- Thanks again!

It is possible that the brakes are not broken in. My '02 Pathfinder developed this pulsation when it was new. It was getting progressively worse after a couple thousand miles and I was just about to take it to the dealer and demand the brakes be changed. Then somebody cut in front of me requiring a panic stop from about 50 mph. The braking rate was about as hard as it could be without invoking the ABS. This was two years and 30,000 miles ago. The brakes have been smooth ever since.

There was a web site passing around recently that had a good explanation about apparently warped rotors that is actually caused by improperly seated pads. Take a look at

Another possibility is that it is not the brakes. My '00 Acura developed a severe pulsation when braking from highway speeds. The symptom was that of a warped rotor (the same as what you describe). It turned out to be a weak spring and a failing upper ball joint. The dealer first tried to sell me rotors until I asked them why that side of the car was an inch lower than the other side. Once they replaced the ball joint and spring, the braking problem went away.

The third possibility is the obvious one - the new rotors are crap.

I wouldn't recomend braided lines, especially if they aren't the DOT approved kind. Seen too many of the "race" type lines break on steet cars and I never could feel any difference. I think most of it is in people's heads claiming they "feel" better. I'd buy some good rotors/pads before I bought stainless lines! :-) Brembo and Mountain brand rotors both seem to be high quality.

While this can be part of the problem, cheap rotors are susceptible to thickness variation which will make brakes shake something awful. They are correct that rotor "warp" i.e. what you can measure with a dial indicator doesn't make them shake. I've seen rotors with .005"+ of runout, which is WAY out of spec, brake perfectly smooth while .0005" of thickness variation will shake like crazy.

Also, I've seen the specs change dramatically when the rotors heat up. I think that's another major difference in rotor quality and shimmy.

Exactly. The cheap rotor's thickness variation will change with temp/use and turning them may stop it for a short period of time but -will- return.