Need some help here.

I replaced front brakes, pads and rotors, about 2k ago. About 500 miles after bedding the front left started doing the constant cyclic squeal at low, 5-25, mph.

Constant Cyclic Squeeking

Fast forward a little while and they started doing a constant hum at low speed and high pitched noise at high speed until the brake pedal is applied.

So I thought the pads were fword, so I replaced those 2 weeks ago along with all new pins and retainers.

Now the problem is worse. I took the front apart the last 2 saturdays and checked everything. Rotors are fine, not any glazing, and the caliper pistons all seem fine.

I got fed up and took it in to Toyota to have their techs inspect it. The tech recommended a full brake fluid replacement at $170. He believes the issue is due to air in the system.

Has anyone had these issue, and were you able to solve it with fluid flush?

Any other ideas?

Toyota pads?
I’ve seen a few occasions where the aftermarket pads were too thick and contacted the rotors all the time.

thats my first guess. Aside from that check backing plates. Air in the lines most likely won’t cause brakes to drag but a spongy pedal or poor stopping power instead. Obviously something is dragging when it’s not supposed to be so I’d bet the farm the pads are aftermarket OR a caliper is dragging
Good luck!

Pads and rotors are OE. Toyota rotors with Akebono pads

Agreed. Air in the line doesn’t seem logical. Possible? Yes but not logical. Did you disconnect any lines or anything that would have introduced air into the lines?

I always start at the easiest, most logical place and I agree that non OEM pads might be the first issue. It could be an issue with the master cylinder too. More details please.


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Front Rotors: 4351260191
First set of pads: PTR0989111 - these were the TRD brake pads
Second set of pads were Akebono ACT976 ProACT


I bought the first two through a dealership connection.

I hated the dust from the TRD pads and it was part of the reason I swapped.

From my understanding the Akebono pads are the OEM with integrated shim. The TRD pads I got look identical to the Akebono with an integrated shim.

May seem obvious (if you're not me), but did you install the pads in the correct orientation? I had an issue after doing my brake change and I had two inside pads installed on one side and two outside pads installed on the other side.

See my post about it here.

Hi Justin,

Perhaps check the thickness of the OEM pads and the Akebono pads w/shims right out of the box; just for comparison and see if that has any bearing on the problem... I can't see how air in the lines would cause the pads drag!

rig, cheers!

Have you tried using a product like this disc brake compound. I always use a similar product on disc brakes. https://www.amazon.com/CRC-05016-Dis.../dp/B000CINV88

You’re right about the Akebono pads.

Great suggestion about pad orientation and location. Check that and report back.


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I used the permatex stuff. It's blue vs red hahaha.

I had the correct orientation and placement. Thankfully his post helped with this on my initial install.

Update: I flushed the fluid today. I went through about 2 Toyota DOT 3 bottles before the air started releasing and there was a good amount of air in there. In total I went through 4.25 bottles at 12oz until I had a clean smooth fluid coming out.

After the fluid flush the constant hum/whistle went away from the front LH side. The constant cyclic squeak I reported was actually the LH rear wear indicator. Replaced with OEM pads and no more noise.

Thank you to @TrdinOhio @joesrcool @rigtec @Decipher @03_4x4Runner for your input and help

Hi @tristero

So glad to learn that you have made so much progress since your original post; it's great to have so many good people behind us! 'Best to you ALL',

rig!