Problem With Brakes? Creaking Sound

[cduluk]

Hey guys,

Recently i've noticed something unusual with my Rx400h, specifically while braking. Whenever i need to brake hard, i hear a creaking sound- just for a split second, just before the car comes to a stop. It's not the typical "grinding" sound brakes make (that sound is still present), this is something different.

I took the Rx out for a spin and got the sound on tape. You'll notice the mysterious sound followed by the typical "grinding" sound brakes usually make once the car is stopped. However the first time i break, the car doesn't even come to a stop and you can hear the sound isolated from the usual grinding sound- it's just a weird "creak-creak" sound.

Here's the video:

http://www.youtube.com/watch?v=7saY_NJSejg

I only noticed this sound recently, but i'm not sure if it's always happened and i never noticed it until now, or whether there is something wrong with the car. The brakes are still "good" and there's no "squeaking" sound indicating that they need replacement. Could it be a problem with the suspension? Or is this normal? I was thinking it might just be the anti-lock system but i've never heard this sound from any other car with anti-locks...

It doesn't "only" happen when i brake hard, it happens even during light braking too, as i notice it a lot during normal driving. Also, it usually occurs during low speeds... It's quite annoying...

The car's an 08 and it has ~62,000 miles.

Any input is appreciated!

[RX400h]

That does sound like a component is loose (not normal) to me. I'd remove one of the front tires and examine the calipers while someone applies the brakes. However, if the sound occures only when the vehicle is in motion, the problem, if any, many not be obvious. My guess is that a spring or clip that keeps the brake pad up against the piston is loose or missing.

By the way, one of the most commonly misplaced words in the english language is the word "only".

For example, your statement, "It doesn't "only" happen when i brake hard...." should be changed to:

"It doesn't happen only when I brake aggressively...."

Notice that your intent was to describe "when", not the verb "happen".

Also, you should never use a word like "hard" or "fast" as an adverb. They should be used to describe nouns such as "fast car" or "hard material".

[maseace]

Does it only happen during the transition from regenerative braking to friction brakes (~9 mph)? I find this happens if the rotors have a layer of rust from being wet, but as soon as this wears off, they are normal again. It's much more noticeable on the Prius since it's a lighter-weight car.

[cduluk]

Does it only happen during the transition from regenerative braking to friction brakes (~9 mph)? I find this happens if the rotors have a layer of rust from being wet, but as soon as this wears off, they are normal again. It's much more noticeable on the Prius since it's a lighter-weight car.

It doesn't seem to be related to the regenerative braking- i just tried putting the car in neutral, and it did the same thing.

Also, after leaving my class today i noticed the sound after applying pressure on the brake pedal to get the gear in D. So the car doesn't even need to be moving for this sound to occur!

Here's another clip, just in my driveway in PARK with the ignition ON. Just pressing the pedal down all the way and releasing causes the same sound... First time the sound was pretty loud, the second time nearly gone, and the third time only a little bit.

http://www.youtube.com/watch?v=H63481el0ic

[cduluk]

I also found a thread from a while back with a list of TSB's for the 06 Rx400h which lists something that might relate to the problem i'm having, but i'm not sure if the 08's are affected or if the problems are even the same.

http://us.lexusownersclub.com/forums/index.php?showtopic=58929

see TSB 5.

[lemon]

It sounds like you're farting in that last video.

Anyway, is that noise coming from inside the vehicle, or outside? Since there is no traditional vacuum booster in the hybrid, there is some sort of mechanism that senses the stroke of the brake pedal and converts that into braking force etc. etc. Maybe that is what is creaking, but you would hear that inside the vehicle I think.

**edit** yes..the TSB refers to this...

[cduluk]

haha... it certainly does sound like that.

And it's definitely coming from the outside of the car. I can't tell which side though.

[maseace]

Must be air in the brake lines like the TSB says. Have you ever replaced the brake fluid?

[cduluk]

Must be air in the brake lines like the TSB says. Have you ever replaced the brake fluid?

Well, as far as i know the brake fluid's never been touched- but i didn't own the car until it was at 42k miles, so it may have been done before that. The fluid level is at the normal level that's all i know.

[maseace]

According to the maintenance schedule, the brake fluid should be changed every 30k miles. Supposedly brake fluid absorbs water over time that can overheat (boil) and develop air in the lines, which can cause problems.

[cduluk]

According to the maintenance schedule, the brake fluid should be changed every 30k miles. Supposedly brake fluid absorbs water over time that can overheat (boil) and develop air in the lines, which can cause problems.

Oh i guess it was changed then, because it had all of its scheduled services before i got it at 42k miles. So i guess its due for another?

[RX400h]

Not changing your brake fluid would not result in air in the fluid and moisture would certainly not cause a clunking sound.

[gwgang]

There may be two possible reasons: 1. The cold weather and the snow+salt may be playing a number on your brake pad/rotor. The pad may make noise when cold, or scrapping rust/road salt from the rotor;

2. The brake caliper's pin may have seized. That's what happened to me, and I heard noise like yours.

[cduluk]

I'm going to have to have the car checked this weekend...

[Ryals]

Your brakes should be dissembled and inspected. The slider pins inspected for synthetic brake grease. New anti-rattle clips and pad anti-vibration shims should have been installed. *If there are anti-vibration shims your brakes will make noise till the end of their usable life. *There is a trick to correct brake noise if there are no shims. The mechanic should apply CRC Brake Quiet to the clean steel side of each pad.

If they installed semi-metallic brake pads on your car, shame on them. If wagner brakes pads are not used ceramic pads should have been installed! Metallic pads will grind the living dog meat of the faces of your new brake rotors and will leave a dirty brown / red coating of dust on your wheels and tires.

If the problem still exists, the lower ball joints and inner and outer tie-rod ends should be inspected.

[RX400h]

Now that's a guy who knows what he's talking about!

[lemon]

Your brakes should be dissembled and inspected. The slider pins inspected for synthetic brake grease. New anti-rattle clips and pad anti-vibration shims should have been installed. *If there are anti-vibration shims your brakes will make noise till the end of their usable life. *There is a trick to correct brake noise if there are no shims. The mechanic should apply CRC Brake Quiet to the clean steel side of each pad.

If they installed semi-metallic brake pads on your car, shame on them. If wagner brakes pads are not used ceramic pads should have been installed! Metallic pads will grind the living dog meat of the faces of your new brake rotors and will leave a dirty brown / red coating of dust on your wheels and tires.

If the problem still exists, the lower ball joints and inner and outer tie-rod ends should be inspected.

It's making the noise while it's in PARK, so the vehicle is not even moving. I think this would rule out ball joints/tie rods etc, and vibration of the pad since the rotors are not turning.

My guess is still with the brake actuator or some related part.

[cduluk]

Hey guys, I just wanted to update on this issue.

I never ended up taking the car to have the noise checked last spring, but I thought the problem solved itself. In April, I made the mistake of changing the brakes myself since they were due for replacement. Well, I must have done something wrong because I got a bunch of lights up on the dash and I had lost most brake function. I ended up having to take the car to the dealer and have them bleed the brakes for an hours labor! Apparently that's what happens when you change the brakes on this car??

After that was done, I didn't notice the noise anymore, so I assumed it was related to them bleeding the brakes. I didn't hear the noise all summer, until this past week.

The noise is back, just as loud and annoying as before!! I'm guessing it's related to the cold, since the temperatures here have dropped to about 60 during the day and 40's at night.

What do you guys think I should do now? I really don't feel like having to pay another hours labor at the lexus dealer, but I'm also not sure if this noise is covered under warranty.

Thanks for any input!

[lemon]

Unfortunately, you can't bleed the brakes on the hybrid in the same manner as in a non hybrid as the brake pedal is not directly connected to the hydraulic system. The system has to be connected to the Lexus computer thingy (handheld thing for diagnostics etc.) and the electric pump that creates pressure in the brake hydraulic system has to be cycled that way. I wish there was some way to jump a wire, or fuse or something to do this and save a trip to the dealer.

However, if you're just changing pads/rotors, there should be no need to bleed the system. Only if you've changed a caliper or somehow managed to introduce air into the hydraulic system would you need to bleed the system.

[cduluk]

Yeah, i'll know that for next time the brakes need changing.

But the issue i'm having now with the "noise" isn't related, i don't believe. Would this noice be covered by the warranty? It only happens when it's cold and i'm not aware of anyone else experiencing this...

[ESSBEE]

Hi, I am having the similar issue with my RX-400H and the noise comes while it's in PARKING, so the vehicle is not even moving.

Is there anyone who could help. Its really annoying and just due to that i did repalce the whole brakes but the problem remains the same.

Thanks and looking forward.

ESSBEE

[RX400h]

Did you replace them, yourself or have a shop do it? If you had the shop do it, recently, then take it back. They could've done something wrong.

By the way, most people who change/have changed their brakes SHOULD have the brake fluid flushed, especially since most people do not have the fluid flushed every 2 years.

[happygodee]

Did you ever find out what this noise iw? I have a 2008 RXH 400 and it makes the same noise. I took it to a shop today and had my brakes checked out and had the electronics checked and they said all is well, they couldn't find a problem. He did mention it could be the actuator and recommend I take it to another shop that could check for that.

[ESSBEE]

Hi, I still have the same problem, but what i notice is that in winters the noise is not that much but in summer it really get louder. Dont know but it is still there and i dont have any response from the forum guys.

I changed gthe brakes from the motor mechanic not my self who changed the routers and the brakes.

Looking forward for the resolution from my forum friends.

Thanks

[maseace]

I'm pretty sure it's just the pulsing effect of the ABS kicking in. Mine does it right before the car comes to a stop, if I hit the brakes a little too hard.