knocking sound from front brake caliper

dave666 · Nova Slayer Joined: 02 Sep 2012 Karma :

So Basically i tried to ride away with my disc lock on lol...

since then i can hear a knocking from one of my front brake calipers where the disc lock has whacked. I've taken it off and it all looks fine, nothing warped and then put it back on securely.

but it's still making a knocking sound. I can forcefully move the caliper by hand (only a little) by grabbing it from the bottom of the caliper and moving it upwards so there is still some play in it which is obviously vibrating as i ride. whenever i squeeze the front brake the noise stops.

Is there anything obvious i should be looking it?

poleposition · Two Stroke Sniffer Joined: 10 Dec 2013 Karma :

sounds to me like you have distorted the disc somewhere, It may look perfectly round and true, but I bet it isnt.
If you can get the front wheel up in the air so you can spin it then use some crayon held firmly against the fork or caliper and just touching the disc you should be able to spin the wheel and see where it is distorted (unless you have a DTI gauge which is even better)
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bladerunner · World Chat Champion Joined: 09 Sep 2006 Karma :

What bike is it? Sliding calliper or fixed? Same with the disk. Is it floating or solid? Either way sounds like...warped disk,does the brake lever pulse when you brake or calliper/disk mounting bolts need inspecting or there should be a mark left at the point where the disk lock hit the calliper and disk end where the lock was attached. It might have left a high spot where it locked up.

Doubt it would have done loads of damage as you would have been doing max a couple of mph...but needs checking further.
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dave666 · Nova Slayer Joined: 02 Sep 2012 Karma :

Snorty · World Chat Champion Joined: 13 Oct 2010 Karma :

Sounds a lot like a warped disc.

I did similar on a bike. The knocking will be the caliper moving from left to right as it travels with the warped part of the disc.

If you watch the caliper while you're riding along (if you can see it) you will see it going from left to right and vice versa.
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dave666 · Nova Slayer Joined: 02 Sep 2012 Karma :

Is it a cause of a new disc then or can it be repaired?

TheCatSatOnTh... · Scooby Slapper Joined: 30 Nov 2013 Karma :

If it is warped, then there are people out there who can straighten it. I'm considering these guys for my warped disc but haven't had the chance to even speak to them yet.