Help Please 🙏 Back Brake Issue

[admmcg]

Hi all,

New member here and absolute n00b mechanic! As in, I know pretty much next to nothing!

I've got an issue with my back brakes, only one of the two 'pincers'(?) Seem to be gripping the disc. The front brake is working fine(looks as though both 'pincers' are gripping) the back brake works, but not very well or reactive enough.

I've attached pictures, I'd be extremely grateful if someone could help at least point me in the right direction of the problem. Even just informing me of what the 'pincers' are actually called would be a great start!

 

[rogerzilla]

Some disc calipers are designed like that, although it's a bit nasty. The disc bends to contact the other pad.

Assuming it should be centred, the method varies by model. What is it?

 

[MichaelW2]

The fixed pad usually has some kind of adjustment bolt for moving it closer to the disk. It should be as close as posdible without rubbing. You access the bolt through the spokes.

 

[admmcg]

Some disc calipers are designed like that, although it's a bit nasty. The disc bends to contact the other pad.

Assuming it should be centred, the method varies by model. What is it?

Thanks for the reply, it's a Carerra Vulcan

 

[presta]

Some disc calipers are designed like that, although it's a bit nasty. The disc bends to contact the other pad.

The rear brakes on my Honda Accord were like that. Instead of two pistons, the calliper had a floating mount that allowed it to move as the pads wear.

 

[rogerzilla]

That's typical of normal cars, but on the bike version the caliper doesn't even float - the disc has to warp slightly. Tektro Io are like that, I think.

These brakes should be Clarks Clout if it's a recent Vulcan. To centre them, loosen the two bolts that secure the caliper body to the frame or fork.

Do NOT undo any bolts that hold the caliper body together, or you will get fluid everywhere and will be in a world of pain!

Hold the brake "on" at the lever and securely retighten the two bolts. The brake should then be centred.

 

[I like Skol]

That is a fixed hydraulic caliper so 'should' close/grip equally from both sides.
If it doesn't then either the caliper is not centered on the disc (see instructions in previous post) or one of the pistons has seized.

 

[I like Skol]

Just to add, one of the two bolts you need to loosen is shown in you picture and is in the middle at the top of the pic. The other bolt will be exactly the same but below the caliper where we can't see it in your pic. It will need a 5mm Allen key.

 

[roadrash]

@admmcg With regards to centering your brake callipers , all explained in the first 1 minute of this video , its exactly the same procedure on your vulcan.

View: https://www.youtube.com/watch?v=gQ_oIAPuQR8

 

[roadrash]

it wound me up posting that ^^^^ , just because the title contains the word "hack" .....why the f3ck is everything a "hack " lately

 

[admmcg]

Thanks for all the advice will try the above method today and post the results!!

 

[admmcg]

Hi 👋

So I tried the above method but no joy.

Looked in to it a bit more and a possible problem could be contamination of the brake? As it seems to be working but not actually gripping the disc as it should?

 

[roadrash]

Then its time for new pads and a damn good clean of the disc