12jimmyjam

Hi all. So I had my rotors and pads replaced by a local shop a few months ago (I've probably got about 10k miles on them now) with aftermarket parts. The pads are ceramics and the rotors are zinc plated. I love the setup and it's been feeling like a brand new car in terms of braking with very little dust despite having a mega commute.

Over the past week I've noticed a knocking sound coming from the rear area when nearly stopped. It only occurs when the brake is applied at low speed and the car is nearly stopped. I checked out the car on ramps yesterday and didn't find any loose exhaust pipes. Lug nuts are tight too. It sounds as if someone let an average household door knocker comes to rest. Any ideas? Thanks!

Blue Moose Engineering

Does this car have little drum brakes inside the rear rotors for the parking brake?

ESh

Correct, it has little drums.

Blue Moose Engineering

What is being described sounds like when the shoes are grabbing the drum and knocking or when something in the drum is loose. That's my guess.

12jimmyjam

Thanks guys. I think I'm taking it to the dealer once I get off of work. I'm guessing a drum issue as a lot on the internet says the same.

Is the rear drivers side where the parking brake connects to? I'm thinking that's where I'm hearing it.

Also had to have the car towed via rollback last week (totally unrelated issue). Any chance this could have played a role in this? Thanks!

jkayca

What do you mean by rollback? Do you mean the car was lifted by the front and towed? If so, was the parking brake on? That could cause some serious damage to the parking brake.

Blue Moose Engineering

Both sides should have parking/ebrake drums. I've never seen a car with a one side ebrake...this is not to say they don't exist, but most passenger cars are not built this way. If you were to actually use a one-sided ebrake in an emergency situation the car would spin...or using it in a parking situation and the car would roll, pivoting around the one locked wheel...

Clutchless

A rollback is slang for a flat bed tow truck wherein the bed "rolls back" so the cables can pull the car onto the truck.

jkayca

Thanks! I never knew that.

I suppose the car could still have damaged if the operator did this while the e-brake was on.

Blue Moose Engineering

Ya that could be bad for the ebrake for sure but it might be tough to say if that is what caused your problem.

12jimmyjam

Got a call from the dealer today and they attributed the noise to aftermarket brake pads. I don't plan to change them because the brake setup has been great except for the noise. Very little dust despite my mega commute and they haven't developed the shudder that I usually get even when using oem pads after a few thousand miles.

Some interesting notes:

Tech test drove it around the building and originally thought it was due to warped rotors. Turns out they were ok.

Got to drive a ES hybrid for a loaner. I wasn't a big fan of the less smooth drivetrain but it was still a nice ride. I think I averaged around 35 mpg with my long trip through the country to a wedding today. I originally thought it was breaking traction over and over but it turned out to be the lane departure feature kicking the steering wheel in the right direction. Pretty cool stuff.

Grand total for the bill with service loaner and diagnostic was $5. The dealership that I went to in Northern Virginia has some issues with customer service and basic competence (misquoting prices, arguing with me over repair needs, joyriding in customer vehicles, etc.). I worked with a particular service writer before who was the definition of professional (which should be the standard at a lexus dealership) and asked for him when I went in. While he was busy, he agreed to work with me. On the way out, I slid him a $40 tip and the tech who road tested the vehicle with me $20. Turns out the well deserved tips paid dividends and they ignored the usual $150 diagnostic fee they told me it would cost. Also pretty cool stuff.