shine2000

There is a problem going on when I'm adjusting the toe in of my v brake pad.i use a card and and brake the lever and to level the brake pad with rim so it's even.but after I tighten the bolt of the brakepad the back of the brakepad goes up but not the front.
like this.

I'm not talking about during the tight in process but after it just goes up by itself magically which ruins the toe in.in the picture the back of the brakepad is too high but front stays same place.

canklecat

Try a zip tie instead of a card. I find it easier since it keeps my hands free. After all the adjustments seem right clip off the zip tie with fingernail or toenail clippers.

JoeTBM 

Great idea, you should be able to leave it a little loose (and still stay in place) and just slip it off to be reused for the pad next adjustment.

canklecat

Also, some V-brakes are a PITA to set up and keep adjusted. My comfort hybrid has low end Tektro V-brakes and the springs won't hold a set. Periodically I need to rebend the springs to get even closing and opening. Just twiddling the adjustment screws isn't enough. It could probably be fixed permanently with better springs but I only ride that bike for errands and haven't bothered.

And looking at the photo above, the OP's brake cable may need to be replaced. That kinked cable might be thwarting fine adjustments. Since best thing I did to improve braking and shifting on my other hybrid's cantilever brakes and shifting was to replace the cables and cable housing. Took me a year to finally agree with the usual advice to do so and it really did help.

Eric S.

I love V-brakes but will never understand why the springs often need to be readjusted after removing a wheel for a flat, cleaning, etc (I have Shimano on two bikes).

mtbikerinpa

That is probably due to drift in reinserting the wheel. It is very easy on a slot dropout(vertical or horizontal) to get a slight off from where it was before. It is pronounced all the more with disc brakes.

The pads may be affected by deformed cone washers. They are aluminum casting which has some ability to be deformed from torque which can make them prone to setting in one spot. The solution is to remove them and reinsert in a different orientation or in extreme cases, sand them down or replace.

canklecat

Torsion springs with long legs are harder to heat treat correctly compared with flat leaf and full coil springs. The coil segment is probably heat treated well enough. But low end brakes cheap out and use torsion springs that appear to be wound without any follow-up selective heat treatment to ensure a good set on the long legs. Fine for devices that don't see a lot of use cycles but not good for brakes. The manufacturers probably figure the bikes these springs go on won't be ridden more than a few hundred miles in total, ever.

Some of my friends who kept their 1980s classic mountain bikes eventually reworked the components and swapped the original cantilever brakes for V-brakes. I should ask them what kind they got and whether they held up as well. I've kept the canti brakes on my '92 Univega because they work. All I needed to do was switch from the stiffest spring setting to the middle of three settings.

shine2000

So it turns out nothing was actually wrong with my brake pads other than greaseing the mounting bolts and I notice that I had the wrong side of the brakepad toed in.and then another issue I had was that the wheel was not true! While adjusting the centering after the right toe in way, one side of my rim was uneven and way too close to the pad while turning the wheel, and one side looked dead even. So hopefully getting the rim trued will finally fix everything!