Bicycle Mechanics - Gummy, sticking rear brake.

Hey All.

My rear brake pads (V-brakes) are not returning fully to their position after I release the brake lever. Instead, one of the pads remains on the rim and rubs pretty bad. I can return the pads to their appropraite postion just fine with my hands, however. The brake lever itself seems really squishy too, not near as precise as my front brakes. Any ideas? This is on a trek 520 touring rig. Thanks for your help!

Sounds like it could be your cables. You might clean and lube the rear brake cable and see if that works.

1. If the brake releases quickly, but only on one side:

There are two little Allen screws at the base of each leg of the v-brake (near the bosses). By tightening one or both, you increase the tension in the brake and make them spring back more quickly.
Adjusting only one screw increases the tension on that side only and should make the brake release evenly (unless you tighten the wrong screw...)



2. If the brake releases like if it were swimming in molasses:

How large is your frame?

I had a problem similar to that on a 25" frame, especially with the Burley Piccolo Moose rack. The original Trek rack was OK if I moved it to maximum height, and the Blackburn EX-2 had a good 3 or 4 mm clearance.

Problem is that the seatstay braze-ons for the racks are too close to the brakes, so the tie bars are almost running through the brake cable and noodle. A bit of creative bending made the tie bars move closer together, and I now have a full 1 mm gap between brake cable and tie bars.

If you can't solve the problem that way, try to tie the noodle to one side of the brake, or to change its shape or the sape of the flexible cable.

BTW, I suspect the clearance problem is lesser with more "standard" sizes.

The longer cable and additional housing are going to contribute some extra "mush" to the rear brake, no matter what. I bet your brakes will show improvement when you lube the cables, though. Might also lube the brake's pivots themselves, if they've been exposed to much weather.

Thanks for the responses! I'll try to figure it out during lunch today...

i too have sticky brakes, but they're old dia-compe side-pulls. You said lubricate the cables, but with what? I'm afraid that WD-40 would screw up the cable housing.

WD-40 also dries up and leaves a sticky residue. I use tri-flo on my cables occasionally. It has very tiny teflon particles in it. It comes in spray or squeeze bottle.

How old are you cables/housings? Older ones were not stainless and could rust. If they have been on there a while, you might consider replacing cables and housings. Many sources recommend replacing them every couple of years as a matter of routine. Modern cables and housings don't need much lube. I just get a little on my thumb and forefinger and pull the cable through a few times just enough to get a VERY light coating. Too much lube will attact gunk. Stainless cable in plastic lined housing doesn't need much lube. If the brakes were working OK beforeI would avoid adjusting any screws until you make sure it's not just dirty cables. Check the pivot points for the arms, too. They can get gunky and sticky. If the look clean, put a drop or two of TriFlow or other very light oil and work them.

sorry, 520, i dont mean to take over your thread.

Rainman, how old is old? would a decent bianchi bike from the early 80's have stainless cables? theres not much info about bike maintence for this era of bike, most of it is either too old (60's-70's) or too new.