Newbie: need help fixing brakes

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omarm
Posts: 7
Joined: 28 Aug 2016, 12:05pm

Newbie: need help fixing brakes

Post by omarm »

My sons bike brakes need adjusting.
I've seen loooads of videos on youtube and am fairly clued up about adjusting brakes - I think I'm a bit of an expert now!

Problems:

- When the brakes are pressed, one side just stays - it doesnt spring back.
For this, I cant find a single video on youtube addressing the problem (I'm sure there are - just havent found)

- The cable - just doesnt seem to be enough of it. In order to have it so that the brake lever on the handle bar doesnt have to be squeezed too much, then then I have to really close the brake so that the pads are touching - but then the wheel wont run because of the brakes!

See below for a picture:

Image

Thanks.


Omar
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Gattonero
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Location: London

Re: Newbie: need help fixing brakes

Post by Gattonero »

For instance, the noodle is not fixed in the correct way in the Rh brake, also it seem that is passing BEHIND the forks??

You're looking to something like this:
Image
The noodle has to pass correctly, in front of the forks, the cable has to be long enough to not pull, yet not too long to form a very big loop.

Once the cable is correct, you have removed a big problem.
Start aligning the brake pads. Ignore the brake lever for the moment, you can setup the pads by undoing their bolt and aligning the pad and pressing the brake arm against the rim. this way, you get the pad correct to the rim, now tighten enough the bolt. Repeat the other side, then adjust the wire so that you have enough clerance between pads and rim, yet the brake lever has the right travel.

Image
It is by riding a bicycle that you learn the contours of a country best,
since you have to sweat up the hills and coast down them.
Thus you remember them as they actually are...
omarm
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Joined: 28 Aug 2016, 12:05pm

Re: Newbie: need help fixing brakes

Post by omarm »

thanks for the reply.

YES, the noodle holder was where it was because i was trying to repair. :)
i was following a guide on youtube.
the only thing i would say is that it doesnt fit straight but sits at an angle.
the picture i took was upside down from the front.

your advice was excellent - THANKS.

BUT... how do i make one side spring back? it doesnt do this right now :(
do i adjust the spring tensioning screw?

thanks
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Gattonero
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Re: Newbie: need help fixing brakes

Post by Gattonero »

Start by removing the noodle from the brake, so they are free from the cable tension.
You should figure out how to unclip the linear spring off the brake arm. Now see if the brake arm moves free, it should not be tight in any point, nor have too much play.
It is by riding a bicycle that you learn the contours of a country best,
since you have to sweat up the hills and coast down them.
Thus you remember them as they actually are...
markfh
Posts: 210
Joined: 9 Sep 2013, 5:35pm
Location: Suffolk

Re: Newbie: need help fixing brakes

Post by markfh »

Firstly I would release the noodle so that the two brake arms can move independent of each other and then check that both of the brake arms are moving freely. If it the two arms spring out independently of one another then the problem could be uneven spring tension. The one with the weaker spring will effectively be stopped from releasing fully by the stronger spring on the other side. Normally these sort of brakes have three holes for one end of the spring adjustment assembly to go into into. I can see such a feature on the left hand side of the picture you originally posted (below the orange wheel reflector). See also the second of the three pictures against "Step 4" on this web page (https://www.ifixit.com/Guide/How+to+clean+and+adjust+Direct-Pull+Cantilever+V+Brakes/3800) which shows the pin sticking out of the reverse of the arm and the corresponding hole it goes into on the mounting on the frame - both circled in orange.

Have a look at both sides and see if they are engaged in the same hole. You can try moving the assembly on the "weaker" side so that it is then under more tension or that on the stronger side so that it is under less tension, so that both arms need approximately equal force to move them. The adjustment screw can also be used to adjust the relative tension but the position of the pin may need to be changed first if they are not already close (in relative tension). Alternatively you can lessen the tension on the "dominant" side.

If either brake arm is not moving freely then undo the mounting bolt on that side and clean and lubricate the pivot bushes taking careful note of which of the three holes the end of the spring is engaged in before disassembly. Try them again in the original position before trying one of the other positions if the problem was the arm not moving freely
omarm
Posts: 7
Joined: 28 Aug 2016, 12:05pm

Re: Newbie: need help fixing brakes

Post by omarm »

thanks for the replies guys.
i can fix the (or attempt to) side not springing back...
but them i still have the problem of the bike cable being too short.

in regards to putting into a different hole... i saw this on a youtube video where the guy puts the brakes altogether.
so i get that part.
the thing is... the bicycle is only 9 months old. has been ridden maybe 20 times, so surely it couldn't have become that much displaced in that time?
Brucey
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Re: Newbie: need help fixing brakes

Post by Brucey »

omarm wrote:thanks for the replies guys.
i can fix the (or attempt to) side not springing back...
but them i still have the problem of the bike cable being too short.

in regards to putting into a different hole... i saw this on a youtube video where the guy puts the brakes altogether.
so i get that part.
the thing is... the bicycle is only 9 months old. has been ridden maybe 20 times, so surely it couldn't have become that much displaced in that time?


by any chance have you perhaps turned the steering one full turn and wrapped the brake cable round the frame?

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
omarm
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Joined: 28 Aug 2016, 12:05pm

Re: Newbie: need help fixing brakes

Post by omarm »

by any chance have you perhaps turned the steering one full turn and wrapped the brake cable round the frame?

definitely not done that :)
hmm... i'm thinking... maybe i'll shoot a video of my troubles and post. i'll see what i can do. :)
Brucey
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Joined: 4 Jan 2012, 6:25pm

Re: Newbie: need help fixing brakes

Post by Brucey »

omarm wrote:
by any chance have you perhaps turned the steering one full turn and wrapped the brake cable round the frame?

definitely not done that :)


well that is weird because that is exactly how it looks in this picture
Image

it looks like the cable is routed awkwardly (behind the fork?) and it is pulling the noodle out of the brake at a funny angle. The brake will never work like that.

Better still photos that show the cable routing would be helpful.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
omarm
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Joined: 28 Aug 2016, 12:05pm

Re: Newbie: need help fixing brakes

Post by omarm »

ok...
i took loads of pics.
the fork handle on the left is the one that doesn't move.
i pressed and observed, it moves about 20% of the right one.

see pics below. (i don't know how, but the noodle is now sitting straight!)
thanks.

Image
Image
Image
Image
Image
Image
Image
Image
Image
Brucey
Posts: 44521
Joined: 4 Jan 2012, 6:25pm

Re: Newbie: need help fixing brakes

Post by Brucey »

there are small screws at the base of each arm. These adjust the preload on the spring in each arm, thus centring the brake.

You can see that the right screw is wound all the way in and the left screw isn't. Provided both arms are free-moving and the cable isn't awkwardly routed (I'd suggest bringing it forwards so that it isn't touching the frame anywhere) then backing out the right screw should make the brake work better.

cheers
-------------------------------------------------------------------------------
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
MikeF
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Re: Newbie: need help fixing brakes

Post by MikeF »

Edit to add
The right hand brake lever ie front seems to be positioned very far down, especially when compared with the left; the cable from it goes behind the red piece on handlebars. I should have thought that the lever should be more forwards facing making it easier to operate and allowing the cable to be in front of the handlebars, which would make the noodle more upright instead of its rather odd position facing backwards.

Nothing to do with brakes, but it looks to me as though the front wheel should be reversed so the tread faces the other way. I would put the Vs on the top of the tyre facing forwards, but maybe that's how they are supplied. Is there a rotation arrow on the side of the tyre?
"It takes a genius to spot the obvious" - my old physics master.
I don't peddle bikes.
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Gattonero
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Re: Newbie: need help fixing brakes

Post by Gattonero »

Isn't the shop supposed to have the bike checked before been sent out? :roll: :roll: :roll:
It is by riding a bicycle that you learn the contours of a country best,
since you have to sweat up the hills and coast down them.
Thus you remember them as they actually are...
omarm
Posts: 7
Joined: 28 Aug 2016, 12:05pm

Re: Newbie: need help fixing brakes

Post by omarm »

guys, thanks for all the replies.
i tried everything and nothing worked.
i took back to decathlon.

they guy said the screws needed adjusting.
20 seconds later, all fixed an ok.

honestly, i think i spent 2+ hours in total. i'd classify myself as a 'handyman know it all' who can do and fix anything.
i think i need to de-classify myself. lol. :)

BUT... one thing i don't like is the brakes.
they are 1 finger gap from the handle bar.
the buy said this was ok.
it seems tooo close for my liking.
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Gattonero
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Re: Newbie: need help fixing brakes

Post by Gattonero »

From what I can see those are "budget" brakes.
The arms are made out of pressed mild steel, the supports for the springs are plastic, all in all it makes for flex in many areas. This is what will cause the "sponge" feeling and/or not possible to have a short lever stroke. We do assume that the wheels are properly true.
The brake levers do play a role in this, too.

When the pads are worn, consider an upgrade with better brakes, i.e. Shimano Deore can be found very cheap and are infinitely better (also their Shimano pads will brake better) in many ways.
And when the cables will need replacing, consider to replace the levers with matching Shimano, again those can be found for cheap and do come with a full set of brake cables.
It is by riding a bicycle that you learn the contours of a country best,
since you have to sweat up the hills and coast down them.
Thus you remember them as they actually are...
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