Cable disc brake clicking when brake lever is pulled the full way back

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doffcocker
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Joined: 31 Aug 2020, 8:49pm

Cable disc brake clicking when brake lever is pulled the full way back

Post by doffcocker »

Hi all, happy new year.

I wonder if you can advise on what may be causing this (video link attached).
The bike is 2-3 months old and been ridden most days through all weathers.

Thanks.

https://photos.app.goo.gl/nDLngabYeki5JW6Z6
peetee
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Location: Upon a lumpy, scarred granite massif.

Re: Cable disc brake clicking when brake lever is pulled the full way back

Post by peetee »

If it’s moving that far at the lever chances are that the pads are worn out and the clicking you can hear is the pad retaining spring catching on the disc.
The older I get the more I’m inclined to act my shoe size, not my age.
PH
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Re: Cable disc brake clicking when brake lever is pulled the full way back

Post by PH »

I have no idea what the noise is, but that's way too much lever and brake arm travel, the brakes either need adjusting or the pads replacing. from the correct rub free clearance to full on should be about half that travel.
Plenty of online guidance on set up and adjustment, it's usually easier to watch it than have it explained.
PT1029
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Re: Cable disc brake clicking when brake lever is pulled the full way back

Post by PT1029 »

... but first check the wheel axle is fully in the drop outs on both sides. That way the disc will be in the correct position before you try to adjust the brake.
The wheel skewer should be tight to prevent the brake action from moving the axle on the left side.
If the bike is 2 - 3 months old, check with the retailer. Any work might be under warranty, or might fall under fair wear and tear.
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PedallingSquares
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Re: Cable disc brake clicking when brake lever is pulled the full way back

Post by PedallingSquares »

As said there is far too much travel at the lever.Either cable has stretched,needs adjusting or the pads are shot.
For reference my hydraulic brakes are fully on within around 10mm of lever travel, although many people prefer a bit more travel that's how I've set them up going back 20 years.
zenitb
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Re: Cable disc brake clicking when brake lever is pulled the full way back

Post by zenitb »

this sounds horrible and dangerous !!!

Just so we can get more information on the issue is there a pad adjusting screw on the OTHER side of the brake to that shown on the video ?

Something like this?
Pad Adjustment Screw
Pad Adjustment Screw
If there is, is it tight or slack ? And does tightening it change the symptoms ?
slowster
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Re: Cable disc brake clicking when brake lever is pulled the full way back

Post by slowster »

According to your previous threads you have a Decathlon Triban RC520, which is fitted with Promax disc brakes. According to Promax's manual for the brakes, to compensate for the brake pads wearing it has a fixed pad adjuster which requires a 5mm allen key, and adjustment of the moving pad is by the barrel adjuster. Better quality brakes do not use (or in some cases even have) a barrel adjuster to use as the pads wear, and if they have a barrel adjuster it is only used once after fitting the cables to remove slack in the cable. Thereafter moving pad wear is compensated for by a separate adjuster similar to the one for the fixed pad.

Judging by your second video, a lot of the barrel adjuster thread is exposed. Unless it was like that when you bought the bike because a lot of slack had to be taken out after the cables were fitted, it suggests that you have used the adjuster to the point that the pads are now worn out and need replacing.

I suggest you watch/read the Park Tool guidance on cable disc brakes.

https://www.decathlon.co.uk/p/road-bike ... mc=8554265

https://www.promaxcomponents.com/produc ... kes-dsk300

https://s3.us-east-1.amazonaws.com/prom ... _V1_EN.pdf

https://www.parktool.com/en-int/blog/re ... -alignment

https://www.parktool.com/en-int/blog/re ... stallation
pwa
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Re: Cable disc brake clicking when brake lever is pulled the full way back

Post by pwa »

And for any type of cable brake, having to pull the lever back a long way, combined with a barrel adjuster having been screwed out a long way, suggests that the cable may be slipping through the clamp that is meant to hold it firmly at the end. Worth checking, perhaps.
doffcocker
Posts: 178
Joined: 31 Aug 2020, 8:49pm

Re: Cable disc brake clicking when brake lever is pulled the full way back

Post by doffcocker »

zenitb wrote: 1 Jan 2023, 5:20pm this sounds horrible and dangerous !!!

Just so we can get more information on the issue is there a pad adjusting screw on the OTHER side of the brake to that shown on the video ?

Something like this? pad adjuster.JPG

If there is, is it tight or slack ? And does tightening it change the symptoms ?
Hi zenit.

I have had a little play around just now with the screw - it wasn't exactly loose to start with but not tight enough to feel resistance - and having tightened it a little the noise has completely gone and the lever doesn't travel nearly as far back, but there is some slight interference.
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531colin
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Re: Cable disc brake clicking when brake lever is pulled the full way back

Post by 531colin »

See Fausto's post on the thread about BB7 knobs, linking you to a video showing the working of a BB7 disc caliper.
I guess your Promax(?) calipers work similarly; ie 3 tiny ball bearings climb up a ramp to move the pad(s) towards the disc.
Its possible that the noise you had represents the bearings reaching the end of their ramps....this is a problem because as soon as the pads wear a fraction more, the brake stops working.
doffcocker
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Joined: 31 Aug 2020, 8:49pm

Re: Cable disc brake clicking when brake lever is pulled the full way back

Post by doffcocker »

Having removed the wheel, I have managed to get a closer view of what the pads are doing, and as you can see there is still a slight clicking that coincides with the outer pad retracting slightly.

Is this significant?

https://photos.app.goo.gl/x4hvH2dzCvBFhSS78
mattsccm
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Joined: 28 Nov 2009, 9:44pm

Re: Cable disc brake clicking when brake lever is pulled the full way back

Post by mattsccm »

I use a slight ticking on my BB7s to tell me that the pads are (too) worn. It is, as mentioned above, the spring catching.
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531colin
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Location: North Yorkshire

Re: Cable disc brake clicking when brake lever is pulled the full way back

Post by 531colin »

doffcocker wrote: 2 Jan 2023, 1:43pm Having removed the wheel, I have managed to get a closer view of what the pads are doing, and as you can see there is still a slight clicking that coincides with the outer pad retracting slightly.

Is this significant?

https://photos.app.goo.gl/x4hvH2dzCvBFhSS78
Isn't the pad is supposed to move towards the disc?
The pad moving away from the disc suggests the pad has reached the end of its travel.
slowster
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Re: Cable disc brake clicking when brake lever is pulled the full way back

Post by slowster »

I think it may be over camming, as described in these two posts:

viewtopic.php?p=664618#p664618

viewtopic.php?p=626367#p626367
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531colin
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Location: North Yorkshire

Re: Cable disc brake clicking when brake lever is pulled the full way back

Post by 531colin »

slowster wrote: 2 Jan 2023, 4:54pm I think it may be over camming, as described in these two posts:

viewtopic.php?p=664618#p664618

viewtopic.php?p=626367#p626367
I haven't found any information on how the things actually work?
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