Why is my hydraulic disc brake so noisy?

[John F]

I have an issue with my front Tectro hydraulic disc brake. On applying thw brake it works smoothly until slow speeds when it it makes a loud and sort of vibrating noise. It does pull the bike up perfectly though, but that noise!

This is despite renewing both the rotor and pads with original parts. After taking the wheel off to investigate, both the pads and the rotor seem perfect. The rotor is tightened down correctly to the correct torque whilst turning it in a clockwise direction.

I thought it might be loose fork bearings causing a shudder, but I can't see any movement when I have it up on the stand.

The brake lever works as usual with no sponginess or other symtons which might indicate fluid problems.

Any ideas anyone?

 

[Woosh]

hydraulic brakes noise is usually due to:
1. contaiminated surfaces. Check first that there is no oil leak around the piston then clean the rotor with isopropyl alcohol. Let it dry before testing.
2. The pads are not aligned parallel to the rotor. Remove the pads and check that the pads are worn evenly and there are no traces of chips or contamination and refit. Loosen next the two lateral adjusting bolts, squeeze the lever and tighten lightly the bolts. Make sure that the noise is gone before tightening the bolts further.

 

[AndyBike]

Alignment can cause squealing. I use playing cards to initially get the distance equal as playing cards are a uniform thickness.
So say 3 cards one side and 3 cards on the other, or however many you need equally.

After that, if you tie back the lever with an elastic band and leave it overnight, it aligns the pads, as the distance the pistons come out might initially due to stickiness cam come out unevenly, so leaving it 'on' allows the brake pistons to settle.

Sometimes you get a weird squealing when you initially pull the lever gently, but apply more force the noise goes away. This is also down to the pads coming out and impacting the rotor unevenly and the overnight thing sorts that out too.

Care of rotor and pads -
Pads - you can burn off any residue with a blowlamp. Heat till they start smoking, this is any road film burning off, but dont heat them so much the backing plate goes red or anything like that and when heated dont ever cool them down with water as the shock cold can cause the pad material to become separated from the backing plate.
But a bit of heat helps.
After heat, rub the pad face side down on some smooth wet and dry.

Rotors- Wet and dry sandpaper. It will remove any glazing from the rotor surface.
After dressing the pads and rotor you'll have to go through the bedding in process again.

NEVER LISTEN TO ANYONE WHO TELLS YOU THAT YOU CAN USE COPASLIP ON THE BACK OF THE PADS That person is a complete idiot, so DO NOT listen to them.

 

[Raboa]

The distance between the pad surface and rotor is very small. When you use the rotor the metal heats up and expands, the air then cools it down.
Manufacturers will claim to heir rotors are the best and this still happens
Keep your pads and rotor clean, if using different pads then the ones it came with then realign the calipers.
When using new pads don't do sharp braking to bed them in, go slow and slowly brake.
I have learned to live with the squeal and rubbing, it saves you using a bell

 

[matthewslack]

If your Tektro is one of the models that use same pads as many Shimano models, try Shimano pads. BS05, resin, silent.

I check alignment by eye with pads out as the caliper sometimes moves when tightening the bolts. If it looks parallel to my eyes, I have never had a noise problem with BS05 and a disc in good order.

 

[John F]

hydraulic brakes noise is usually due to:
1. contaiminated surfaces. Check first that there is no oil leak around the piston then clean the rotor with isopropyl alcohol. Let it dry before testing.
2. The pads are not aligned parallel to the rotor. Remove the pads and check that the pads are worn evenly and there are no traces of chips or contamination and refit. Loosen next the two lateral adjusting bolts, squeeze the lever and tighten lightly the bolts. Make sure that the noise is gone before tightening the bolts further.

1. I ensured cleanliness so don't think that's the problem
2. When assembling the 2 pads and the spring retainer clip prior to insertion I noticed (I think) that the pad surfaces were parallel pushed together, but when they were NOT pushed within the clip ready for insertion they were NOT PARALLEL i.e. after fixing the wheel back they would still not be parallel and would not contact the rotor with 100% pad area??

Am I missing something?

 

[John F]

If your Tektro is one of the models that use same pads as many Shimano models, try Shimano pads. BS05, resin, silent.

I check alignment by eye with pads out as the caliper sometimes moves when tightening the bolts. If it looks parallel to my eyes, I have never had a noise problem with BS05 and a disc in good order.

I've always used the original pads as replcement, but I note your suggestion.
I'll try your second point again thanks. There is only a very slight catching between pads and rotor with no brake applied

 

[John F]

Alignment can cause squealing. I use playing cards to initially get the distance equal as playing cards are a uniform thickness.
So say 3 cards one side and 3 cards on the other, or however many you need equally.

After that, if you tie back the lever with an elastic band and leave it overnight, it aligns the pads, as the distance the pistons come out might initially due to stickiness cam come out unevenly, so leaving it 'on' allows the brake pistons to settle.

Sometimes you get a weird squealing when you initially pull the lever gently, but apply more force the noise goes away. This is also down to the pads coming out and impacting the rotor unevenly and the overnight thing sorts that out too.

Care of rotor and pads -
Pads - you can burn off any residue with a blowlamp. Heat till they start smoking, this is any road film burning off, but dont heat them so much the backing plate goes red or anything like that and when heated dont ever cool them down with water as the shock cold can cause the pad material to become separated from the backing plate.
But a bit of heat helps.
After heat, rub the pad face side down on some smooth wet and dry.

Rotors- Wet and dry sandpaper. It will remove any glazing from the rotor surface.
After dressing the pads and rotor you'll have to go through the bedding in process again.

NEVER LISTEN TO ANYONE WHO TELLS YOU THAT YOU CAN USE COPASLIP ON THE BACK OF THE PADS That person is a complete idiot, so DO NOT listen to them.

THanks for all this. One further question: Can the pistons become stuck and if so what's the answer? I ask this because when I used a screwdriver to push back the pistons prior to replacing the pads, they did seem very stiff?

 

[John F]

The distance between the pad surface and rotor is very small. When you use the rotor the metal heats up and expands, the air then cools it down.
Manufacturers will claim to heir rotors are the best and this still happens
Keep your pads and rotor clean, if using different pads then the ones it came with then realign the calipers.
When using new pads don't do sharp braking to bed them in, go slow and slowly brake.
I have learned to live with the squeal and rubbing, it saves you using a bell

How many miles is reasonable before they are bedded in would you say?

 

[Woosh]

1. I ensured cleanliness so don't think that's the problem
2. When assembling the 2 pads and the spring retainer clip prior to insertion I noticed (I think) that the pad surfaces were parallel pushed together, but when they were NOT pushed within the clip ready for insertion they were NOT PARALLEL i.e. after fixing the wheel back they would still not be parallel and would not contact the rotor with 100% pad area??

Am I missing something?

They float over a 'dome' and will eventually line up with the pistons inside the caliper. The main thing is you should watch how the pistons move when you squeeze the lever. You want to be sure that the two sides push equally when you squeeze the lever.

 

[AndyBike]

THanks for all this. One further question: Can the pistons become stuck and if so what's the answer? I ask this because when I used a screwdriver to push back the pistons prior to replacing the pads, they did seem very stiff?

Hunters silicon lube.
Pump the pistons out A LITTLE BIT, no more than about 8mm.
Take cotton bud soaked in a solvent, and wipe the sides of the pistons several times.
Take new cotton bud, with Hunters on it and swab the piston sides.
Push them back in.
Pump them back out a little bit and repeat with more Hunters. - push back in.
Dont use a screwdriver, it can damage the piston as they tend to be a bit sharp - a spoon handle is better. And try to push from the center not the edge.
Hunters lube - this small bottle will last years and years.

After youre happy and lubed both pistons a couple of times and pushed them back in, spray some brake cleaner into the slot and wipe out with a clean rag to get rid of any residue.

Pardon our interruption...

www.ebay.co.uk

Many called "Hope silicon lube" because this is what Hope technology use to lube the pistons on their brakes or if they service them and recommend customers use the same.

 

[Bikes4two]

NEVER LISTEN TO ANYONE WHO TELLS YOU THAT YOU CAN USE COPASLIP ON THE BACK OF THE PADS That person is a complete idiot, so DO NOT listen to them.

Hi Andy, I'm not challenging the above but as one who has never had to service hydraulic brakes, I'm curious as to what are the perils of using copaslip (for when I do end up with said brakes)?

Cheers,

 

[Woosh]

When one of the pistons seezes up, I suggest you change the caliper. The Tektro I use is E350. You don't have to use the same model of caliper. If you need help, contact support@wooshbikes.co.uk

 

[AndyBike]

Hi Andy, I'm not challenging the above but as one who has never had to service hydraulic brakes, I'm curious as to what are the perils of using copaslip (for when I do end up with said brakes)?

Cheers,

Its basically a grease, and the last thing you would want is any of it getting onto the pads.
I'll admit theres 2 camps on this one. Im in the what if camp. I have also heard It can affect the seals as well as obviously the risk of melting as it has a low melting point, and isnt really recommended for high temps, especially if you drag your rear brake on hills etc, with the risk of it soaking into the pad material, which would not be very good for braking performance

Just to clarify. If it were used, it would go between the piston and the back of the pad, not, repeat not between the pad and the rotor lol.

Some say it helps deaden any vibration, but I think the risks are too high and no grease type should ever be used in a disc brake.
I think I'd rather have a slightly squealy brake then no brake at all. And more often than not the noise is due to misalignment or contamination.

 

[John F]

Its basically a grease, and the last thing you would want is any of it getting onto the pads.
I'll admit theres 2 camps on this one. Im in the what if camp. I have also heard It can affect the seals as well as obviously the risk of melting as it has a low melting point, and isnt really recommended for high temps, especially if you drag your rear brake on hills etc, with the risk of it soaking into the pad material, which would not be very good for braking performance

Just to clarify. If it were used, it would go between the piston and the back of the pad, not, repeat not between the pad and the rotor lol.

Some say it helps deaden any vibration, but I think the risks are too high and no grease type should ever be used in a disc brake.
I think I'd rather have a slightly squealy brake then no brake at all. And more often than not the noise is due to misalignment or contamination.

I have an issue with my front Tectro hydraulic disc brake. On applying thw brake it works smoothly until slow speeds when it it makes a loud and sort of vibrating noise. It does pull the bike up perfectly though, but that noise!

This is despite renewing both the rotor and pads with original parts. After taking the wheel off to investigate, both the pads and the rotor seem perfect. The rotor is tightened down correctly to the correct torque whilst turning it in a clockwise direction.

I thought it might be loose fork bearings causing a shudder, but I can't see any movement when I have it up on the stand.

The brake lever works as usual with no sponginess or other symtons which might indicate fluid problems.

Any ideas anyone?

 

[John F]

I've sorted out my noisy brake problem. Thanks for the advice.

I took the caliper off, removed the pads then, after some effort with a large tyre lever, managed to wiggle the pistons out enouth to clean the edges with a cotton bud and disc cleaner. After applying some hydraulic fluid to the edges of the pistons I attempted to push back and push out several times hoping the fluid would ease the movement of the pistons (It was the outside one which seemed for seized up than the inner one) Although I was still apprehensive, because the pistons were still not moving at the same rate as each other, the noise has virtually vanished I'm pleased to say.

Which leaves me with a question. Is it a good idea to lubricate the pistons at regular intervals to prevent seizing up and if so what's the best way?

 

[Woosh]

. Is it a good idea to lubricate the pistons at regular intervals to prevent seizing up and if so what's the best way?

How many miles have you done so far? It's been good in the last 4 years and you've fixed your pistons, I would leave it as it is.

 

[John F]

How many miles have you done so far? It's been good in the last 4 years and you've fixed your pistons, I would leave it as it is.

7100 miles. Rear brake never had a noise problem

 

[Woosh]

7100 miles. Rear brake never had a noise problem

rear brakes work half as hard as front brakes.