TripleAce

Im trying to adjust the back brakes. But I'm coming across an issue I cant seem to fix. I managed to fix the front ones well. IN the sense there close enough but not touching the rim, and they both close together while the tension is strong enough on the brake lever.

But with the rear brakes, I keep having a problem of the right side closing and opening but the left brake pad simply closes but doesn't open back up, so it ends up always touching the rim. If I move the calliper that way there both even from the rim, once I press the brake lever, same thing. The left side only close but doesn't open back up.

What adjustment should fix this please?

Thanks all

mkadam68

Couple issues I can think of:

- Gunk/dirt/oil clogging up the return spring within the brake caliper itself, or
- A kink/dirt/gunk/oil clogging up the brake cable within the cable housing. Probably just want to replace (if a kink, definitely want to replace). Or check with a LBS, they may just be able to blow the gunk out with a cleaner under pressure.

Right Said Fred

Single or dual pivot?

TripleAce

im pretty sure its a dual....any suggestions?

TripleAce

Yea its possible, except that the bike is basically new. Maybe some lubrication?

TripleAce

Yea its possible, except that the bike is basically new. Maybe some lubrication will help

TripleAce

im pretty sure its a dual....any suggestions?

Bob Dopolina 

What brand? Model?

Did they come on the bike or did you install them?

Have you taken them apart for any reason? Or just adjusting them?

Could the cable housing be too long and pushing the calipers to one side?

Have you adjusted the fine set screw too far and the balance is now off?

And, as other suggested, is it all gritty in there or dry as a bone?

TripleAce

here some of the things I tried.

1. I first screwed the barrel fine tuning adjustment all the way clockwise so the calliper are far apart
2. Then I loosen the cable bolt and pushed both callipers pretty close to the rim
3. once tighten then I went back to the fine tuning barrel adjustment to adjust a little more. maybe a little closer or further depending.
4. Now they seem just right, but the I press the break lever and they both move and both close, HOWEVER the left side doesnt go back to its original place, but the right side moves outwards.

I even loosen the bolt that centers the calliper but no matter what once I press the lever the left side always basically stays closed and doesnt really move back outwards. Instead the right side's gap is even a bit larger since the left side doesnt really move.

Gege-Bubu

I just had the same problem, the LBS is fixed it.
The problem was a lose screw that holds both "arms" on the "axis". They had to take the brake completely off the frame, the hex screw I am talking about is the one that is located exactly above the top of the tire. The tech said it should be all the way in.

I just assume your read brake is exactly as mine. I have stock Cannondale C4 brake. And yes, cleaning and lubing cable/housing is good too.

TripleAce

Oh and not gritty in there, there basically new and came with the bike. Just bought the bike a few weeks ago. I never removed them just fiddled with them to get it right. They shouldnt be dry but I guess thats possible. I did the front and there perfect. super close but not touching, good tension and they both move in and out together. But maybe I got lucky and didnt really realized what actually allowed the front breaks to adjust so well.

TripleAce

This is what my calliper looks like. Im guessing you mean the middle screw in the picture?

Bob Dopolina 

Did you adjust either of the nuts on the front of the brake? Those can sometimes cause binding.

To center the caliper you need to use the nut BEHIND the brake calipers, not the ones on the front.

TripleAce

Yea I played with the rear nut and that was to center the calliper. The front nut made the calliper's tension hard. So if I screwed it all the way tight the calliper's movement for be tight. So If I pressed on the brake lever the calliper wouldnt open at all. So I left that a little lose.

Basically even if I loosen the rear bolt and center the calliper, once I press on the brake lever they both close at the same time but one the right side just opens more and the left side ends up not opening very much. so much that it looks like its touching the rim.

Gege-Bubu

No, not that screw. It is tiny hex screw underneath, facing the tire. I had to take my brake off to adjust it

Bob Dopolina 

Is there a small set screw on the side of the caliper (or in the side of the arm) that you can turn? This changes the balance on the spring and could be the problem.

TripleAce

I just checked and I dont have a hex screw on the bottom of the calliper. This is probably a reletively cheap calliper I think. So the adjustments are not as stable or as easy.

Basically I only have 4 things I can adjust on this calliper.
1. The rear middle bolt
2. The front middle bolt
3. The tension cable bolt on the left side
4. The fine tuning adjustment barrel
and I guess
5. the position of the break pads but that has nothing to do with the callipers.

So it has to be anything from 1-4 that should make it good. I mean I could simply spread the break pads apart with the fine tuning adjustment barrel on the left side but its would be optimal breaking.

TripleAce

Hi, No I dont have a small screw. the only things I can adjust are:

1. The rear middle bolt
2. The front middle bolt
3. The tension cable bolt on the left side
4. The fine tuning adjustment barrel
and I guess
5. the position of the break pads but that has nothing to do with the callipers.

Bob Dopolina 

I think this is your answer.

If not, you need to tighten the two front nuts together and so they are not causing the brake to bind and them leave them alone.

If there is no set screw I'd suggest tapping the spring to one side or the other to balance the tension. You can do this by putting a flat screw driver on the inside of the loop on the spring, giving the screw driver a tap or two and then checking the brakes. It is not the most elegant solution but I have done it countless times with brakes like these to get the spring centered in the calipers and to even out the tension.

roadwarrior

You broke you back and your rear? Sorry to hear that. Get better soon.

RollCNY

Op~
The two nuts on the outside of the brake are set as jam nuts, and you need to make sure that they are tightened together, as in against each other, with the right amount of tension on the arms so that they do two things:

1) Be loose enough to allow the spring to spread the brakes freely.
2) Be tight enough to keep the assembly from pulling apart as you stop (which is your brakes breaking), or working loose.

It is a balance to get that right. Once it is good, and the two nuts are jammed together, you can make small rotational adjustments by having a wrench on the inside nut of the outer pair, and a wrench on the nut to the inside of the frame. Rotate the two together, so that the whole assembly moves. If you see the assembly move but not the coiled spring, then nothing has changed.

If you can't work it out rotating, Bob D is absolutely on with the screw driver pop method.

And the words brake and break are different. Your brakes will brake the bike, until they break, and then you can't stop.

TripleAce

hahah, woaps I didnt even realize that. I know the difference in meaning and spelling but I instinctively or reckless spelled break instead of brake. sorry

TripleAce

thanks Ill give it a shot today

TripleAce

thanks for the advice Ill give it a try later on today once I'm home.