Since purchase, I have noticed that with moderate brake pressure, the brakes vibrate or pulsate some. Doesn't happen with light pressure.

Does anyone else have experience this?

 

Nope, not experienced it with mine.

BUT - having said that, I have seen some cars that after sitting for a while have an issue with the disk brake rotors. Basically you get some surface rust on the rotors and can feel it when stopping. Should go away soon IF your car had been sitting on the lot for a while. If this isn't the case or it doesn't go away pretty quickly, I'd visit the dealer and let the know your concerns.

 

Welcome to the site, RLAndy.

I've got nearly 700 miles on my new RL and the only vibration I've felt is from flatspotting of the tires, at freeway speed, on some of the cold mornings we've had around here recently. That goes away after a few miles on the freeway. I have nothing on braking.

This is definitely something to mention to the dealer. Could be rotors or poorly balanced wheels.

 

Ususally caused by pad deposits on the rotors. Almost always goes away with some hard braking. Even backing up (be careful) and braking hard will help. Often confused with warped rotors which, almost, never happens.

 

Did you follow the manuals breakin advice of braking gently the 1st 200 miles ?

 

How many miles are on this car? I'm wondering if this might be related to an issue we had with the 2005's? Improper wearing of the brake pads due to poor installation. Thoughts anyone? Otherwise, have you done any serious panic stops? Might there be rotor warping?

 

If you've done a panic stop in the first few hundred miles, or a long hard stop (say, down a big hill to a traffic light) and then not released and rolled forward a bit after, you've probably "tattooed" some brake dust into the rotors.

It's probably not "warped" rotors, because that almost never really happens.

The best thing to do is go somewhere on a nice deserted stretch of road and do 2 or 3 hard decels (not stops, and not suddenly enough to trigger the ABS) from 60 to 5 or so, without fully stopping, then drive around and let the brakes cool off before coming to a full stop. If you can smell brake pad, you're doing it right. If that doesn't work, then you might have to get your rotors resurfaces.

Hot new brakes at a dead stop will cause fusing of the pad material to the rotor surface. This then feels like warped rotors. It will eventually wear off... but it's annoying as hell in the meantime.

 

In many years of road course drving I have never seen a ventilated (2 plates with an air space) rotor warp. I have always done my own brakes, have helped/taught numerous other people with theirs and have never seen a warped rotor. And this is in the most abusive conditions you can imagine.

I have seen them cracked clean through but never warped. In fact I can't tell you how many times a student would come to a high speed drving class with "warped" rotors only to have them, miracously, "unwarp" with hard drving.

I certainly can see why people think they have warped rotors because turning them on a lathe fixes them just like it would fix a truly warped rotor. But my bet is always the same.
1. A rotor that isn't square on the wheel hub (infrequent)
2. Pad deposit on the rotor (very frequent).

BTW the old single plate rotors, of days gone by, did warp frequently, particularly if they were cross drilled and has help prepetuate the myth.

Here is some good reading:

http://www.stoptech.com/tech_info/wp...rakedisk.shtml

 

The RL has about 600 miles on it and came with about 250 miles from the dealer. The vibration or slight pulsing was present from the beginning and I thought it would go away. Never had a panic stop and have braked moderately since purchase. I'll try the hard breaking from 60 to 5mph and let you know. I'll probably check with the dealer also. It seems that nobody else is experiencing that sensation.

Thanks!
Andy

 

Tatooing the rotors could easily have been done by someone during test drives or demo, given that it had 250 miles on it from the dealer.

If it doesn't go away with repeated hard braking, tell the dealer to resurface the rotors and while they're at it, do the brake pad TSA...

 

Thanks for the link, I learned something from it!

 

Those 250 miles sound like demo miles ?. If they are warped I am sure they will give you new rotors.

 

Purchased my car this week and it has the same thing you are describing with the brakes. Another car on the lot also did it, but much worse than mine. The build date on mine is from May '06 and I bought it with 8 miles. If it does not improve in the next few days I will bring it in to be looked at (currently have 60 miles on it).

Otherwise a fantastic car; way better than my previous TL.

Bob

 

I also drove a second RL with same pulsation with moderate (almost hard) brake pressure. I had under 200 miles. Mine improved somewhat with the hard breaking from 65mph to 5mph. Will try it once more .....then to the dealr. Thanks.

 

Tried the semi-hard braking in an attempt to help matters. If anything, the problem is worse when the rotors are hot. One of my rotors is also unusually scored. I think one of the rotors is worped and needs to be turned. Bottom line is I now have 230 miles on the car and the brakes are not getting better. It has to go to the shop because XM NavTraffic stopped working, so I will have them also look into the brakes.

What a terrific car, but not a $50K car. However I would buy it again in a heart-beat for the great price I got.

Bob

 

Don't true the rotors, have Acure replace them a pair at a time. If they true one you will only get minimal use from it meaning maybe only one more trueing before needing to be replaced.

 

Miner,

Good point. I had this happen many years ago and both rear rotors were replaced. Dropping the car off in the morning. Will post results when I get the car back. BTW, XM Nav Traffic up and running; didn't realize system reports don't seem to go out on the weekends.

Bob

 

Just got the car back from the service department. As soon as I told the service writer about what was happening with the brakes, he knew exactly what it was and said it is not unusual when the cars sit on the lot unused for serveral months. Front rotors were ever so lightly re-trued and the problem was solved. Brakes feel great now. RLAndy, this is probably the solution to your similar situation.

Bob

 

Thanks,

I bet it is due to the vehicle sitting a the dealer for months before sale.
Will need to call them.
Andy

 

I don't want to be a wet blanket, but what would sitting at the dealer's lot have to do with it?

A light coating of rust will form on the rotors if a car sits unused for any length of time, but that wipes right off the first time or two the brakes are used and doesn't hurt a thing. Other than that, I can't imagine how sitting would make a car's brakes vibrate.
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Brake pad buildup. It's much more easily done with oxidation already present on the rotors. I encourage people to do an entire bedding in process whenever they have new pads. Replacement or on a new car.

 

So, Rich, are you saying the brake pad buildup will occur on a new car just from sitting on the lot? I mean, does the pad material migrate from the pad to the rotor all by itself? I'm not talking about after it's sold and driven away, since the implication is that the whole problem arises from the car just sitting too long on the lot.

I've never heard of that one, but I'm here to learn. Or have I somehow missed the point?
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Save the sarcasm.


The oxidation encourages pad build up in the early operation of a vehicle.

One of the proceedures to go through, particularly with high performance braking systems, is to get the rotors very clean and then go through a complete 50 to 5 pad bed in process.

 

Rich, there was no sarcasm intended. The OP and one other said their dealers attributed brake vibration to the car having sat on the lot a long time. Based on what I thought you were saying, I wondered if perhaps there was some kind of chemical reaction or something that took place to transfer pad material to the rotor. Now I see what you mean.

My sarcasm isn't that subtle.
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Original Post Update: The pulsation improved with the above described hard braking technique, but did not go away completely.

The dealer said a "BULLETIN" from Acura is available to dealers. They replaced the pads and front rotars with "updated" versions.

Problem 100% solved. Excellent service from the dealer too!

 

Great! Glad to hear it's fixed, and good to know there is a known issue in case others have the same problem.
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For a week after I got my RL I experienced similar vibration when braking. Went back to my dealer and they explained that there was a build up on the rotors as the car had been sitting in the lot for a few months. They cleaned the rotors and no more vibration....

 

My dealer cannot find a bulletin on the brake vibration, can anyone help on this or give me a dealer number to call?
thanks

 

bump!

need the bulletin # or TSB # please as my inept stealership cannot find the memo!

 

I checked my invoice and it did not refer to a specific bulletin #