[rightfoot]

For about three years now, I've been trying to find a problem on this 2014 rav4 and am stumped.
I'm not seeing anything that seems to be a danger so I've wanted to solve it on my own before bringing it to a dealer.
I'm at the point where I'm about to bring it in for an assessment but I'm not sure what they will find.

The grinding sounds like the brakes but it's not. That said, the rotors keep getting warped. I know it's the rotors because there is a ton of meat left on the pads and rotors but when I replace them, no more warbling when we hit the brakes.
The pads and the rotors are always nice and clean, no gouges, no nothing obvious.

After I change them, around five to six months later, the warbling starts then the grinding starts. The warbling is highly evident while at highway speeds which sometimes makes me wonder if it might just be an alignment issue but then there's the grinding.

You can hear it even as very slow speeds. I've tried putting more pressure on shorter stops as well as slow, gradual stops but the same grinding sounds. Since the car has 150K miles on it now, I just changed the front bearings thinking maybe when the front end is loading the bearings a little, the grinding is happening due to degrading bearings. No change.

When I change the pads and rotors, I really try to make sure everything is done right and that everything looks ok and it does.

It's the 4 cyl model, Limited edition. I' super stumped on this. What could the problem be?

 

[DL175]

When the rotor was new no grinding. Then 6 months later the rotor got warped which starts to rub on the rotor back plate. It appears to be the rotor getting warped. Which brand for the rotor did you buy?

 

[rightfoot]

Hi,

Correct, it's fine for months then the rotors get warped and the grinding starts. Maybe something is grinding against the rotor when this happens but I see no damage anywhere. No gouges, nothing.

I've tried all kinds of brands, all kinds of pads too from ceramic to cheap to best, always the same thing.
My wife drives the car and I can't help but think she's hitting the binders hard but she tells me she's not doing that. Like me, she did some rally racing so isn't totally oblivious to car stuff.
I wondered about the back plates too but the grinding isn't tinny sounding, it sounds like something you'd see gouging from.

 

[Palex.new]

I've tried all kinds of brands, all kinds of pads too from ceramic to cheap to best, always the same thing.

Hey!
And yet... What rotors and pads have you tried? I always use Advics (both discs and pads) and am very pleased. They brake pretty well, the rotors are not deformed, there are no extraneous noises, are erased evenly.
ADVICS A6F164B (rotors).
ADVICS SN135 (pads).

 

[rightfoot]

Yes but like I said, I've tried a bunch of different brands and price levels. I think my last pads were $100 and no difference.
I really don't think it's anything to do with brands.

I forgot to note that the pads aren't sticking to the rotors either, causing them to heat up. I've tested that countless times, they turn very freely.

 

[Double G]

Have you inspected the calipers and hoses? It could be you have a sticking caliper or the hose is degraded on the inside so that the fluid cannot flow back to the reservoir. I had it happen to a Saturn Vue that I owned. The driver side would be much hotter than the passenger side and coming to a stop I would get a groaning sound. Replaced the pads, rotors, relubed the slide pins and later a new caliper and still had the issue. (Also found that I used the wrong grease to lube the slides of the old caliper and it swelled the rubber at the tip of one of the pins causing it to stick.) Someone on a Vue forum said they had the same problem and replaced the hose. I did as well and the problem disappeared. Apparently the hose degraded where it would act as a one-way valve and keep the caliper pressurized.

 

[Jack Daniels]

I wondered about the back plates too but the grinding isn't tinny sounding,

Sound emanating from the backing plates doesn't always sound tinny or sheet metal like.
Are the plates secure, all the screws in place, not aftermarket, not deformed? Can the plate be persuaded further away from the disk with a hammer perhaps? just to test and see if there is any change.

I guess you have already knocked the plate with various tools to listen for rattles, noise or resonance.

 

[Phatota]

rotors keep getting warped

Rotors do not warp

 

[paulday]

Rotors do not warp

I must have been hallucinating the several times I did brakes while working at the garage and could clearly see the warping when placed on rotor resurfacing machine when the cutter was placed against the surface. I'm sure someone has a nice video on YouTube showing the same thing.

Most of them also had blue discoloring from overheating.

Have a good day.

 

[Phatota]

must have been hallucinating ...Have a good day.

Common experience on the shrooms

In braking systems though its run out ... attached is some lite reading

note: I did enjoy your couched write off

 

[paulday]

OK professor, I'll stick with the mushrooms, and you keep up with the LSD.

Any object that has deviated from its intended shape is by definition warped. I believe that a rotor exhibiting signs of shutter/pulsating at the pedal from any surface deviation can be and is considered warped.

After 40+ years working at my family garages, I've seen rotors that have had a + deviation on one side and the same of deviation on the other side to the -. Warped to me!

Tell a customer that "Your rotor's have run-out that can be fixed if your rotors have enough material left or if not, they will have to be replaced." Blank stares and lots of questions.

Tell a customer that "Your rotors are warped. If they have enough material left, they can be fixed and if not, they will have to be replaced." OK, how much? is usually the next question they ask.

Warped everyone understands. Surface deviation, not so much.

99% of drivers only know that when pressing on the pedal to the left of the gas, the brakes work, and the car stops. That's it. You do know that there are people out there that have trouble gassing up their own cars, right?

FYI, that 9 page of PDF fluff was written by an employee of Centric Parts, who personally has never seen a "Warped" rotor and then showed some stock pictures. Sure, if she was looking for something bent, she never saw a warped rotor. Always look at the source and who wrote it before believing every word. IMHO, the rest of the article doesn't really do her justice either.

Have a good day.

 

[Phatota]

OK professor
Any object that has deviated from its intended shape is by definition warped
Always look at the source and who wrote it

Incorrect and not how warped is defined nor commonly understood. And most certainly not applicable to a rotor, as the shape remains true.

As an industry professional 'After 40+ years working at my family garages' you should cease and desist perpetuating automotive myths

Are you a strict adherent to the do as I say paradigm? It would appear so
Through your apparent misogynistic eyes, you have shown to have no idea who Carroll was ...nor his pedigree

Should you care to keep digging your hole and discrediting yourself, please feel free.
But continue with the preface of knowing I will no longer be assisting in your tutelage

 

[paulday]

Incorrect and not how warped is defined nor commonly understood.

Tell that to the thousands of mechanics dealing with the common driver. I've never heard of anyone being told "Your problem is due to runout of the rotor." 40 years tells me this!

FYI, most of the real informational articles that I've just gone through use the terminology "Warped Rotor" as a catch all for any condition that affects the surface of the rotor from being perfectly flat. Even pad material buildup.

Nobody ever said do as I do. Anyone can use any terminology they want, just don't be surprised by the blank stares.

Reading an article written by an employee of a company reminds me of letting a company handling a complaint using their paid arbitration judge for the ruling. You never win!

This whole conversation reminds me of an issue involving Win95 when it first came out. Plug & Play was the big thing being pushed by MS. Unfortunately, in the real world, to add a CD-ROM drive, you still had to edit the config.sys and auto.config files before installing the CD Drive, otherwise Win95 would not see the drive. Once Win95 recognized the drive and installed the Win95 drivers, you could delete the added lines to the config.sys and auto.config files and Win95 had no problem using the drive. CD_ROM drives eventually came with a floppy disk that would do the dirty work for you.

After failing this question on the A+++ cert test. I had the opportunity to speak with a MSCE about the discrepancy and was basically told that the CD_ROM needed to be Win95 aware for it to be P&P. A little fact that they didn't let out. There never was any Win95 aware CD-ROM drives manufactured and finally, Win98 was truly P&P. In the meantime, us techs were still stuck with editing files when adding second party hardware. But not according to MS.

The reality is that people are going to continue to use "Warped Rotor" when diagnosing a shutter/pulsing brake pedal because it's what the common person understands. Everyone is not a professor!

Have a good day.

I wouldn't expect an answer from you!

 

[rightfoot]

Er, arguments could be taken to some new post instead of ruining mine .

The reason I believe they are warped is because as soon as I change them out, no more wobbling when using the brakes. Add to that, I've started having them turned and when I re-install the old ones, no wobbling.

The weird thing is, there is no rubbing, no overheating, no uneven wear on the pads and as I mentioned, lots of meat left on both the pads and the rotors. While my wife is a bit harder on breaking, she's not hard enough on them to warp from constant hard braking or anything else.

Also mentioned, I just replaced the bearing assembly as well so when I took those apart I looked at everything even closer and there is nothing obvious. The plates were also very secure, there's nothing loose, the hoses are in good shape and I can tell the brakes aren't sticking because of the way it picks up speed on even the smallest decline.

And what I mean by wobbling is when you hit the brakes and the front end kind of wobbles, typical when you have warped rotors.

Could it be an alignment issue? I've not considered that much since changing the rotors always fixes the problem for months.

 

[Double G]

Lift up the front end and wiggle the tire by holding it at 12 & 6 and then 9 & 3. You could have worn steering/suspension parts.

 

[rightfoot]

When I've had the vehicle off the ground, I checked and there was no play what so ever in the tire/wheel assembly.

BTW, this vibration wobbling that I mention does not happen only when braking hard or softly, it's random once it starts happening. It's almost as if it's once the brakes heat up a bit.

One thing that is highly noticeable is simply touching the brakes at highway speeds, 65+ for example. Just touching them gets the front end vibrating. At slow speeds like city driving, there's not much vibrating but then there is the grinding.

To me, the two things seem to be separate problems that happen after the new pads/rotors have been in use.
The rotors warp (gonna read that pdf later) and a grinding sound starts to happen. The only one that's obvious is the rotors since changing them removes the problem for months but both the pads and the rotors are perfectly smooth when I take it apart to replace.

 

[rightfoot]

I quickly read the PDF and while it's interesting, it's also overly technical for this problem.

There are no patches where heated materials are building up on the rotors. As I said, they are perfectly smooth with no blemishes what so ever on them.
The PDF is mainly referring to experiences based on racing translated to daily rides. This car is mostly only driven around town and we live in a small down. She might hit 55 at most now and then and mostly in the 25-45 range.
There is not much chance that the brakes on this rav can get so hot that much of the PDF might apply. The PDF talks about high temperatures and other somewhat racing related thoughts back to civilian vehicles but this happens even in winter time when it's not so hot outside that summer heat might play a role.

I suspect this thread will never end and I probably should not have posted it. I probably need to bite my tongue and just take it in to see what the dealer says. I'm just nervous that they will find something that they say is the problem but really isn't and I'll waste time and money later repairing what ever they suggested. On the other hand, you would think they see enough of these cars that a seasoned mechanic will be able to understand the symptoms and spot the problem quickly.

I think the rotors are changing shape since changing them removes the vibration and their surfaces look appear perfectly smooth and not like some of the explanations in the PDF.

However, I think there is something in the front end that is out of alignment or failing that may be causing perhaps a minor vibration that we cannot feel for months but enough to start causing some damage to the rotors or something else or both.

Anyhow, we'll take it in, see what they say and then I'll update this post with what ever they tell me. Even if it's embarrassing, I'll share it in case it can help someone else. It will be a while before I can update this as they are booked solid.

 

[Double G]

Keep us posted.

 

[paulday]

There are two things that I would take a look at before giving up.

Upper Strut assembly bearings. Creates a grinding sound during movement and can also affect handling during braking.

Upper A-frame bushings where the A-frame attaches to the frame. Once they lose their stiffness, can cause steering issues when applying the brakes.

These are the most overlooked items when checking a front end for excessive noise/play issues or random wobble issues.

Good luck.

Have a good day.

 

[rightfoot]

Only thing is, there aren't any handling problems really other than the things I've explained.
I mean, it doesn't pull to one side or prevent braking etc.

Those are good ideas however and I've looked but maybe I missed something. Any tips on how to check the struts properly?