2019 Toyota RAV4 Froxzen caliper

after 26k miles brakes were grinding1 side was metal on metal other side has some pad left our mechanic thinks caliper is defective but dealer denies this, but has not given us an explanation for the uneven wear

When you say other side you do mean other wheel side as in passenger vs drivers side and not other side of the rotor on the same drivers vs pass side right???

What was the remaining pad thickness on the “other side”??
When brakes wear down low sometimes the bond (glue) will let go and then you have instant grinding…

Brakes can wear out due to how they are driven, the way the driver brakes, left foot drivers tend to rest their foot on the pedal and that can cause premature wear…
Yes calipers and brake hoses can cause uneven wear but so can caliper slide pins stuck in the calipers not allowing the caliper and pads to be able to slide…
Some vehicles just simply wear out brakes faster then others…even side to side…

You have to replace your brakes if you want to drive so if the dealer thinks they are ok then fix them and drive it, BUT after driving for a while and doing the normal braking you do, when you get to were you need to go get out and check with a temp gun or your hand and feel (be careful not to burn yourself) the wheel to see if one is much hotter than the other one is…

Also if a caliper is locking up you can get a pull when braking, so get somewhere FLAT and SAFE and let go of the steering wheel (keeping hand very close to the wheel) and hot the brakes to see if the vehicle pulls any…

1 Like

One side is almost always going to wear out sooner than the other, sides are never matched perfectly. My guess, the dealership is correct. From what you say, there is no definitive evidence of caliper problem. Until there is such evidence (for example one side is consistently hotter than the other), replace the pads on both sides, and continue to monitor the pad thickness. It’s possible on my Corolla to visually assess remaining pad thickness simply by removing the wheel for a look-see.

Among the many cars we have had in our family fleet are Toyota Celicas, Supras, Camrys, and a Highlander we still own. Every one of them has suffered from premature brake failure and repeated frozen calipers. The Highlander needs new calipers about every 50,000 miles (we have replaced all four corners twice). By contrast, the Mazdas, Subarus, VWs, Hondas, and Acuras we have owned have never suffered any premature brake failures and have never had a single frozen caliper. The good news for you as a vehicle owner is that brakes are a finite repair with a finite cost that is pretty manageable. Find a good local shop since your RAV4 is no longer under warranty, and change your brake fluid every 30,000 miles or every 2 years. Let us know what the end fix is for your RAV4. How Much Do Brakes, Brake Pads and Rotors Cost? - Car Talk


It appears his good local shop wants to sell him new brake calipers, but the dealer disagrees with this.

At 2 1/2 years and 21000 miles my 2012 Camry had the drivers side rear caliper freeze solid with rust… Replaced only the one caliper,contrary to conventional wisdom and have not had a caliper or uneven problem since. I still have car but I retired completely in 2015, don’t drive much anymore and it only has 59,000 miles on it now.

THe last set of rear pads and rotors I replaced were 3 years ago were incredibly cheap.$62 for Detroit Axle from Ebay. The original Toyota brake pads and rotors always made a grinding noise after every rain., the car is parked outside for the last two years and the brakes are incredibly silent. The fronts are Wearever gold from Advance.

For anyone who doesn’t know, I live in an extremely high salt area, suburban Buffalo.

Funny, last week I was behind a dark blue RAV4 who’s center brake light was on constantly, couldn’t tell about the tail/brake lights because of the sun.

But anyway, you need to respond and answer some questions. Are all the brake pads in need of replacement? If so, the calipers are probably OK, can’t tell for sure without seeing them but I suspect the dealer is right.

With several Toyota’s in the family over many years, never had a caliper freeze up since they dropped the old bushing design back in the 80’s. The bushing design were notorious for freezing up no matter the manufacturer.

I work at http://theautollama.com and all we do are brakes.

Ive seen newer cars (less than 50k miles) have calipers fail often. Is it a factory defect? Who knows but the most common way to tell if a caliper is bad is un even pad wear from one wheel to the other. Now by unven I mean one side grinding and the other side still having between 30%-50% pad life left. I ran into this last week on a 2019 ford explorer with 48k miles one rear caliper seized causing the pads to start grinding while the orher side still had 50% pad life left.

Id ask to see the pads if they are in fact this uneven your mechanic is correct.

1 Like

Good post @dgibson2550_185726. Since you are a brake expert, just curious, in your opinion what causes one pad to wear faster than the other, referring to two pads on the same caliper? I’d guess both pads would wear at the same rate b/c they are sort of squeezed with the same force, especially when there’s just one piston.

My 2005 4runner had a caliper design problem. I was replacing calipers on that truck every 18 months (or sooner) for the 300k miles I owned it. And from the 4runner forum I was on, it was a very very common problem. After my second set, I bought a set of a NAPA lifetime calipers and kept getting them replaced for free, so it just cost me my time. I also replaced the solid brake line hose that connect to the caliper to make the job significantly easier.

1 Like

Well since you didn’t get an answer from @dgibson2550_185726, I will offer one. You already know that when you press on the brakes, the piston pushes the inside pad against the rotor while also pushing the caliper body away from the rotor. The caliper body hooks over the outer pad so it gets pulled into the rotor by the movement of the caliper body sliding on the pins. The only thing that doesn’t move is the caliper bracket. The pins allow this movement.

When you release the brakes, friction moves the pads away from the rotor. The piston moves back into the caliper body removing pressure from the inner pad and the caliper body slides outward to relieve pressure on the outer pad.

If the caliper pins get sticky, that is they don’t allow the caliper body to slide easily, then the outer pad wears out faster than the inner pad. When you apply the brakes, you put a LOT of pressure on the caliper to force it to move. But when you let up, there is not nearly the same amount of force to move the caliper back. The piston retracts to take pressure off the inner pad. But the caliper body has very little force to make it move the outer pad away from the rotor.

As a result, the outer pad is held closer to the rotor, increasing the friction and resulting in more wear on that pad.

EDIT: I should add conversely if the caliper floats easily on the pins but the piston does not want to retract for some reason like maybe some blockage in the brake hose or corrosion on the piston itself, it will not wear out the inner pad first. The floating caliper will stay centered over the rotor keeping the pressure equal for both pads. However, both pads would wear prematurely and the result would be the brakes on this one corner of the vehicle would wear faster than the other wheels, assuming the calipers on the other wheels are working properly.


Ah, so it is caused by sticky caliper pins. Makes sense. I’ve been replacing disc brake pads for 45 years, VW Rabbit, Corolla, pretty easy diy’er job. But I never understood why the pads on the same caliper could wear unevenly until now. Good explanation @keith , thanks.

The caliper below had seized guide pins, the outer pad stopped making contact with the rotor resulting in a badly rusted surface. The inboard side of this rotor and the other three rotors had clean surfaces.

That is a serious seizure to stop the caliper from moving when the brakes are applied. That had to hold back hundreds of pounds of force. But I did have that happen too me once, but only one pin seized because it warped. Not sure how it got bent but it did. The result was the outboard pad wore at an angle because the other pin allowed that end of the caliper to float.

EDIT: actually both pads wore at an angle because the whole caliper would go at the rotor in a cockeyed angle.

1 Like

I’ve seen a lot of caliper slide pins get that stuck, normally from pad slapping and or not cleaning and lubing the slide pins and brackets… O’Reilly’s keeps a lot good selection of caliper brackets, so that lets you know they are selling a lot of them…

1 Like