Rear Brake

[Joe24]

Finally decided to ask for some advice about this.
My back brake is not releasing right. When i pull the back brake, one side releases the other doesnt. I have cleaned the pads incase it was something on there, wiggled everything around, tighted up the cable, this made it better, but it still just catches on one side. I was going to take the whole thing appart, but i cant seem to get the bolt un-done. I get the hex key in and start to put pressure, and it just wont budge.
I've put some oil on it, to see if that will help, but so far it hasnt. It isnt the spring, because i have already checked that. The only thing i can think of is to undo the cable, and widen the distance between the pad and the wheel, but i'm not sure it will help. What seems to happen is when i pull the brake leaver, the cable that goes along the frame goes tight, then when i release the lever, the cable just goes really slack.
It happened when i was on the club ride, it was ok when i went into the cafe, but when i came out and started to go, it started it then. The bike did get alot of dirt on it, but i have cleaned it up as much as i can, but it still does it.
Any suggestions?

 

[Smokin Joe]

Sounds like a sticking cable. Unclamp it and see if the caliper moves freely, if so then fit a new cable.

 

[Dave5N]

Is it a V brake?

 

[Monty Dog]

Sounds like a 'sticky' pivot - particularly the centre one with a dual-pivot caliper. As you've tried allowing some oil to penetrate the pivot, then you're probably going to have to take it all apart, clean up and lubricate all bearing surfaces and then re-assemble. Some of the pivot bolts are probably secured with small grub screws - you'll need a small allen key to release them. Clean up surfaces with steel wool / wet and dry, apply grease. You'll probably need to apply Loctite to secure the grub screws too.

 

[Dave5N]

Or is it a dual pivot?

 

[spandex]

Unclip the cable and unhook it from the frame so you can move all the outers down to the brake. Now get your chain lube and coat the cable moving all the outers so the oil gets in side. Put it all back togever and see how it is and if its still not right the side that is not releasing tighten the grub screw gust a bit. Now see how it is you may need to let some out on the over grub screw.

 

[llllllll]

I've had this problem before, as suggested above the only way to cure it is to strip the whole brake down, clean and lube everything. One thing I found helped stop it happening again (so far at least) was to bent the spring so the two ends were further apart, a couple of pliers/mole grips should be enough. The brake will be slightly heavier to operate, but it'll release with more force, so shouldn't start sticking again.

Probably stating the obvious, but the bolt you've having trouble with may have a grubb screw holding it in place.

 

[Dave5N]

Or is it a cantilever?

 

[Joe24]

Hello,
It is a Dual Pivot brake. I took the brake off the bike, and it seems to not be moving as well as it should. I did loosen everything and put some oil where everything pivots, thats helped abit, but i am going to take it appart completely and give it a good clean.
I'll also tighten/loosen the grub screws and see if that works.
The grub screw that i needed was right underneath the brake, where i couldnt see it.
I ran out of daylight, so what i might do it take it off tomorrow and take it in the house so i have better light to really look at it.
Cheers
Back to trying to revise now.

 

[Dave5N]

As SJoe said, change or at least clean and lubricate the cables - GT85 is fine - you don't want them too sticky.

 

[mickle]

If its your new bike Joe take it back to the shop. It's covered by warranty. If you can wait until May I'll fix it at the show for you!

 

[Joe24]

If its your new bike Joe take it back to the shop. It's covered by warranty. If you can wait until May I'll fix it at the show for you!

It is indeed the new bike Mickle. I'm going to have a look at the brake tonight, i'll take it appart and put it on the table( trying to hide it from my mum, not too keen on having bits of bikes in the house) and give it a good clean. Before i put it back on the bike i'll oil the cable. It that dont work then i'll ride it back to the shop.
The show could be a tad too long to wait though Mickle, anyway how hard can this be.

 

[Joe24]

It appears, i have done it. I couldnt take it appart completely, just loosen everything enough to get a cloth in and wipe it. I loosened the bolt thats in the middle abit aswell and that made everything move freely. I just have to put it back on the bike, and hook everything back up again.
So hopefully what i have done has worked.
Cheers for the help.

 

[Joe24]

Spoke too soon. The back brake still doesnt want to release, it was fine when it was off the bike, but it is sticking again now. I've cleaned the and oiled it, but the brake is still sticking. I'm going to take it off again, but that bolt i couldnt undo before, is still not moving, even when i take the grubb screw out. Thats the one that is stopping me from taking the whole brake appart.
Any suggestions for getting the bolt that dont want to move off.

 

[Monty Dog]

What is the make of the brake? Normally warranty doesn't cover you for 'wear and tear' so you'll need to sweet-talk your LBS if you need to get them to sort it. Normally it's the centre-pivot, so you have to loosen the first pivot, remove the arm in order to get to the second pivot. It happens with the best of brakes - I've recently had to free-up a Chorus and Mavic SSC caliper recently - more to do with the crappy weather we've been having lately.