I have a Nissan Maxima 2001 with around 150,000 miles on it. The front brake rotors have been replaced twice and re-machined once in last 6 months by Pep Boys. The pads were replaced all three times with ceramic pads. The repair is OK initially. A month or so after repair, each time, a brake vibration, which feels like rotor warp, keeps coming back. Or, it could be stick-slip. The net effect is a pulsation in braking at the frequency of the wheel rotation. It does not seem like ABS, which normally has a much higher frequency.
I’ve owned the car for 10 years. The brakes have been an occasional problem, typically lasting 2-3 years before onset of this vibration, but nothing like this frequent onset.
What could be the underlying, root cause of this repeated warping, if that is it? Mechanics are telling me my brakes are warped. I know that. The question is, why?
A Sticking Or Dragging Brake Caliper That Rarely Ever Fully Releases Could Overheat The Brake Rotor, Warp It And / Or Telegraph Imperfections In The Rotor To The Steering Wheel.
Sometimes in the process of retracting the caliper’s piston to make room for new, thicker brake pads, the result is a sticky piston, especially when the vehicle accumulates age and miles.
I’d drive it and then use an infra-red noncontact thermometer to compare rotor temperatures. I have one and carried it in my car to troubleshoot a similar problem. I drove the car long enough to cool the brakes, headed up a hill with no traffic, and then let the car coast to a stop on the roadside before I checked the rotors.
A good mechanic should be able to check for a dragging caliper with the car on a hoist, but the problem may be intermittent.
A caliper that is no longer “floating” can cause this, too. Perhaps careful inspection of the pads and comparison of pad thickness could help narrow domn the culprit.
CSA
Are those tire guys using a torque wrench to tighten the stud nuts correctly?
If not, they may be warping your rotors themselves.
FYI machined rotors, being honed thinner than the original rotor, is suseptible to warping from even a slight over-torque.
What could be the underlying, root cause of this repeated warping, if that is it? Mechanics are telling me my brakes are warped. I know that. The question is, why?
Pep Boys.
Get new good quality (may have to go OEM) rotor and pads (of the type specified for you car), and have someone more qualified put them on. They should also check to make sure that none of caliper slides are sticking or binding and the same for the pistons. Also make sure the lugs are hand torqued on. Don’t ever turn the rotors, they are sure to warp after that. Just replace them.
I am not sure what I would measure with the infrared thermometer or what that measurement would tell me. Am I looking for a circumferential temperature variation? Isn’t it obvious that I would have that if the brakes are grabbing more or less around the circumference, cyclically? How is this a diagnostic tool?
If the piston is sticky or the caliper is dragging, or no longer floating, what is the remedy? Can they be lubed, re-built, or what?
They told me they were using manual a torque wrench, but I did not see it.
Thanks for the clue about machined rotors going bad more quickly. In my case, I had two new unmachined rotors that went bad, so that is useful information but not the answer to the problem.
This seems like good advice technically. Unfortunately, the dealer wants $110 each for the rotors. I can imagine the dealer brake job costing $600 with no guarantee that they would find a caliper problem if there were one. I can probably get yet another brake job free at Pep Boys. So I guess the question is, how long do I keep going back there vs. making a larger investment at the dealer? Do you think that if I told Pep Boys about the torque wrench and the potential sticking caliper issues they could handle it, or is the dealer the only rational choice at this point?
The thermometer Is Useful To Locate A Sticking Or Nonfloating Caliper. The One Rotor That Is Hotter Than The Others Is The Culprit.
A sticky caliper should be replaced. A caliper that stops “floating” or sliding can be cleaned up, the carrier cleaned up and lubed and get new hardware installed.
The fact that these guys keep doing the same thing over and over and expecting different results is not a good sign.
CSA
Do you want it fixed right or not ?
You’re getting what you pay for, self explanatory. ( the dreaded P word )
There’s your obvious reason for the price difference.
I get pretty tired of this “I can’t afford it” crap when in fact…
You can’t afford NOT to.
Why would you want to go to a dealer to (a)buy parts and (b)get service done, unless the vehicle is under warranty or the repair is a recall?
Do yourself a favor and hunt around for a reputable independent shop. Try to locate one where the head man owns the property, as this makes sure he/she isn’t going to be pulling wool over anyones eyes or selling parts not needed and can actually save you money in the long run.
Ensuring the customers are happy enough to return (and recommend) to the same shop for future repairs ensures the head mans future too.
Dealers are parts changers. They just go to their parts bin for what they need rather than try and save the customer money. Not all, but most.
Independents phone around to different suppliers for parts to get you the best price. (At least mine does)
Let me rephrase your question and see what your answer would be.
“So my doctor says I have indigestion, but according to a medical site on the internet I really have an appendix that’s about to burst and kill me. Do you think if I told my doctor that, he could do the surgery and I’d be ok?”
If you have to tell a mechanic to check the calipers after repeated warping issues, it’s like having to tell an Olympic swimmer that water is wet. If he doesn’t already know it, he’s probably not gonna do so well when it’s time to do his job.
I am not a fan of Pepboys or the parts they carry. Find someplace else that uses higher quality parts.
Thanks, all. You have made the point clearly that I need to abandon Pep Boys and that an independent reputable mechanic would be my best bet. I will try to find one, starting now. Is there a good web site for finding and checking candidate mechanics in one’s local area?
It’s often assumed that a brake shudder of pulsation is caused by the brakes and even many mechanics assume this. There are a number of things that can mimic a brake problem; loose suspension component, loose wheel bearing, etc. and in some odd cases even a tire can cause this.
There’s a reason why the problem may not be present at first and then reappear later on but I have a question. Is this shudder/pulsation most noticeable in the steering wheel or the brake pedal/seats? Or both?
I don’t think you have a parts problem as much as a diagnostic or method of repair problem.
You’re at it!
I’ve used it with success.
As for brake parts, using ‘name brand’ brake parts (such as Raybestos, Bendix, and Wagner) would be fine, the cheapest parts will yield poor results.
Thanks for the link. I had found it myself with Google. It’s location on Car Talk home page was not obvious, but I eventually found it there, too, under Ownership. I homed in on a guy with all 5-bar ratings.
I feel the shudder/pulsation in several ways. Mostly by the “seat of my pants”. I feel that the car deceleration is pulsating that the brakes are being applied intermittently, with the same frequency as the wheel rotation. I get some feedback in the wheel and the brake pedal, too. It does not seem to be a wheel shimmy. I can get this at high speeds when applying the brakes, and, after the problem has gone on for some months (as now), I get it at very low speeds too, such as slowing down to stop at a light.
Sure sounds like warped rotors to me.
At 150k miles it’s possible this problem could be due to a loose wheel bearing or suspension component. The reason for asking about the wheel and seat, etc is to try and determine if the problem is in the front, rear, or both. Do this.
Take the car out on a deserted, smooth road and run it up to about 50 MPH. Now bring the car slowly to a stop with the park brake only. Keep your foot off of the pedal.
If the car slows down smoothly the problem is in the front. If it shudders or pulsates then it’s the rear.
Warped rotors or rotors with a parallelism problem is not a guessing game. Rotors can be easily checked for either problem with a dial indicator and micrometer.
The reason why a loose wh. bearing or susp. component can cause the brakes to act fine at first and go downhill quickly is that all rotors develop a little warp after some driving. This is generally not enough to notice. Once they develop a little warp in them combined with looseness in the susp. etc. that warpage is magnified because it starts an oscillation in the rotor.
If you do the test and the car stops smoothly, meaning it’s in the fronts, then I suspect the problem is a suspension or wheel bearing fault; unless these guys are just flat ham-handed and are somehow managing to mangle a simple job.
Assuming everything else (wheel bearings, calipers, etc…) are right, in lieu of the overpriced OEM rotors, I would get a set of NAPA ultra premium rotors (or whatever they call their best quality rotors), and put them on myself, making sure the wheel nuts are torqued properly. I find NAPAs best rotors to work very well, and they are often half the price of OEM parts.