PTCS

2004 RX 330

Upon inspection of an abnormal noise during braking, I found that the inner pad on my front right caliper had lost all of it's friction material and is bent. One small chunk of material did fall out upon removal, so I suppose that MAY be why the pads backing plate is bent (uneven pressure). There are about 35000 miles on these pads, and we drive very easy. There was not any noticeable pulling during braking.

It's obvious I need new pads, and probably a rotor, but I would like to know what caused this. Were the pads installed incorrectly? Is the caliper bad? Was it just a fluke thing?

Thanks in advance.

ELITech

What worries me in this picture is the wear lines on the caliper bracket itself, next to the pad backing plate...

Are these just dust lines or lines worn into the bracket?

If they are worn into the bracket, I fear you have an ear on the knuckle that is bent, causing the issue in the pictures above...

If it is just dust, then my question is are the pads factory, or are they aftermarket? I have seen aftermarket pads have their lining separate from the backing plate caused by poor manufacturing...

Other questions, did you have any work done to the right front before the noise started? Maybe a wheel bearing, etc?

PTCS

You bring up a good point about the caliper bracket. I think the grooves shown were mostly just in the dirt/dust, but I will take a closer look. I put the car back together so I could move it back into the garage until I get parts, so I can't check it right now...maybe tomorrow.

At the moment, I do not know where I got the pads (working on this). I buy a lot of my parts online through Sewell Lexus, but not everything. I checked my Sewell purchase history today and these pads weren't in it. I did find the receipt for the rotors which are Centric brand (reviewed well here on ClubLexus at the time). If the pads are aftermarket, I can assure you that I didn't run down to the local parts house and buy the cheapest set they had. I regularly WAY over think these types of purchases to try and get OEM level quality for less money.

There has not been any recent work on the suspension. The last major work done on the car was the timing belt last Fall/Winter.

A couple of months ago, I had checked the rotor temps for no particular reason and found this rotor (front right) to be about 20-30 degrees warmer than the other three. I poked around here on CL but saw nothing that seemed related. I thought maybe it was just because that rotor is the closest to the engine and 25ish degrees didn't seem too alarming. I suppose I may have missed the boat on catching this early?

mitsuguy

iTrader: (2)

wheel bearing is bad - allowing the rotor to contact the brake caliper bracket

also why that wheel / rotor is hotter...

the bracket is immobile - it is attached rigidly to the knuckle - the only way to get the rotor to contact it would be to have a wheel bearing that is allowing for play...

ELITech

The reason I asked if a wheel bearing had been done is that I have seen guys bend/crack the ear on the knuckle where the caliper mounts to. This happens when they use a hydraulic press to push out the bearing from the knckle...

However, if no wheel bearing has been done, I agree there is a good chance you need to replace it.

PTCS

I very much appreciate the suggestions. I don't believe the wheel bearings have ever been replaced. We purchased the car in 2011 with 60k miles, it has 110k now. Lexus NSH shows no major repairs, just a radio replacement and some rattle fixes.

Is there a way to verify a bad wheel bearing without the dial caliper method. We hadn't noticed any noise other than during braking. I have lifted the wheels and rolled and don't feel/hear anything. Placing a pry bar under the tire does not reveal any noticeable slop. I read about holding the strut spring while spinning the wheel to feel and there MAY be a little vibration, but we are talking about so little that I can't even decide for sure if it's there.

I wouldn't at all question the bad bearing suggestion except that most of the friction material was missing from that one pad, and it had to come out somewhere. I can't help but think that the marks in the caliper bracket could have come from the pad material breaking away during braking. I have not yet RE-removed the caliper for closer inspection though.

mitsuguy

iTrader: (2)

Get the wheel and tire off the ground. Grasp firmly at 3 and 9 and rock it back and forth. Feel for a light or heavy clunk. Repeat at 12 and 6... Any movement at all in the bearing is cause for replacement

PTCS

That's the method I have always used, and I feel nothing.

I am now pretty sure the wheel bearings are fine, or at least not the cause of the pads failure. I pulled it back apart this evening and the marks in the bracket do not line up with where the rotor would have hit if it could. Also, I realized that if the bearing was so worn that the rotor could hit the caliper bracket, there is NO WAY I wouldn't be able to diagnose it with ease....that would be a ton of slop.

I guess I will just assume that the pad just failed for no good reason and replace them and the rotors. I will keep an eye on the bearings and rotor temps. Other than OEM, what brands/types of brake pads do people like for these cars nowadays? I am leaning towards OEM from Sewell, but just wondering about other options.

PTCS

I normally would have done this type of work myself, but at the time had someone staying here that was doing odd jobs to reduce his rent. I think he doubled up on the "shims" that go between the pads backing plate and the calipers piston. Also, since I believe that the OEM pads do not have a shim attached to the backing plate like these, that this is proof I went with something aftermarket (gave up on finding receipt).

Am I correct in assuming that he should not have reused the factory shim with this particular pad? What are the chances this had anything to do with the failure?

ELITech

He definitely doubled up on the shims which is a no-no...

But the top of the picture that shows the factory shims... is that how those two were together?

The reason I ask is because on the factory shims, both pieces have tabs that come off of them a bit...

It looks like in the picture the tabs are pointing opposite directions, and they should all point the same way...

Sucks to see someone get jipped like that

PTCS

I was just checking in here at CL and realized that I never concluded this thread. I ordered new rotors, pads, and shims for all four corners from Sewell and all has been well since. Thank you to all who offered advice and suggestions.