160mm Front Rotor noisy

[fraz101]

My front brake 160mm on my 2021 Giant TCR has been noisy for sometime now.

Usually instantly upon pulling the lever more of a wallowing/drone.

I have replaced the brake pads and sanded and cleaned the rotor,it helped for a while but soon returned.

I have bled the caliper and made sure pistons are not leaking and are retracting evenly.

The rotor isn’t worn beyond minimum thickness and runs true…..

If I sand the rotor and pads and clean it helps for a few rides but soon returns.

Can anyone help?

I am considering replacing the rotor and pads together this time but wanted to ask here first.

Thanks in advance

 

[Drago]

What are you cleaning it with?

 

[bobzmyunkle]

Check for a leaking piston. Take the pads out and look for a small trace of oil on the back. Or dab the back of the pad with a tissue - oil should be easy to see. Only takes a very small amount of oil.

 

[I like Skol]

I once had a similar issue that went on for many months before I realised it was actually a minute amount of leakage from one of the pistons. It was so slight that the oil level never dropped enough to be a problem, but after multiple cleaning attempts and a ruined pair of brand new pads I finally noticed that the caliper body was slightly darker than the 'good' brake. The oil was just migrating so thinly and gradually that the area never looked damp or oily, just kept killing the pads.

Check again that your caliper isn't leaking.

 

[fraz101]

100% no leaking piston

Disc has been sanded various times and cleaned with soapy water then IPA. It helps but only for a short time.

It’s not a squeal,it’s a wallow vibrating noise.

Pads do not look contaminated

 

[BRDUK]

Whats the measurement on the rotor thickness? Id suggest getting it measured if not already done. Looks like there is score marks anyway. Change rotor and make sure pads are clean or new and align calliper correctly.

 

[SpokeyDokey]

100% no leaking piston

Disc has been sanded various times and cleaned with soapy water then IPA. It helps but only for a short time.

It’s not a squeal,it’s a wallow vibrating noise.

Pads do not look contaminated

Try a different pad type?

 

[fraz101]

Try a different pad type?

It had metal pads in to start then I switched to resin, made no difference.

 

[fossyant]

Shimanos can micro leak, believe me. Had some SLX that would leak from the hose connection. So small it wasn't noticeable.

 

[DRM]

Shimanos can micro leak, believe me. Had some SLX that would leak from the hose connection. So small it wasn't noticeable.

This^^^^ Shimano Calipers are well known for the most imperceptible of leaks.
https://www.cyclechat.net/threads/leaking-hydraulic-brake-calliper.284045/

 

[Ming the Merciless]

Have you aligned rotor and calliper recently? If the rotor the same thickness measured multiple points round its circumference?

 

[fraz101]

I've aligned the caliper too many times!

Have attempted to true the rotor (it’s not that far from dead straight)

The noise is worse when lever is initially applied, the harder I pull the lever the noise generally gets less.

I think I will replace the rotor