Bicycle Mechanics - Disc Brake Pads Locked Together

Hey all,

I just bought my first mountain bike with disc brakes, the Trek 6500 with Hayes So1e brakes. Overall I am very happy with the disc brakes and don't see myself ever going back to v-brakes.

The one thing that concerns me though, from reading the forums here as well as from what the bike salesperson told me, is that if you remove your wheel to lock it up or repair it, and then someone squeezes the brake lever, the brake pads can can become locked together.

I seem to be getting mixed info on how to solve this problem. The Hayes website says you should slide business cards into the space until the pads are far enough apart to remove them, then gently wiggle the piston back into its socket.

However, a lot of advice on here says you can just jam a screwdriver into the space and twist it to get the pads back into place.

Yet other people say that when this happens the brake system must be bled.

I know there are a lot of experts on here and I would appreciate your input on which of these scenarios is correct. I know it is unlikely that this would happen, but I just worry how easy this problem is to fix if you are riding around and don't have a full set of tools with you.

I live in Chicago and certain high-theft areas it makes sense to remove the front wheel to chain in the u-lock. If I did this and some jerk came by and squeezed the front brake lever, what would I do?

Thanks a lot for your input. I hope to be knowledgeable about bike maintenance someday soon.

-Mark

You can spread the pads back out with a screwdriver or other thin bladed tool. You need to be careful to not damage the pads surface tho. It is easy to mark them up so a wider tool, like scraper or spatula would be better.
As long as the bike is upright when the lever is depressed and the pads are returned, you should not have a problem with air getting in the system. So you should not need to bleed it out.

It is not to big a deal, there is a mysterious force that draws people to grab the brake lever the second you pop a wheel out. So I have to do this a couple of times a week :)

Yes, I agree with Rev. I just jam a screwdriver in there, and pry apart on the bottom edges of the metal pad backings. This way you wont wreck the pad surface.

I WOULD NOT reccomend taking the pads out. I did this once, and ended up bending the pin on the piston that retains the pad. This is not fixable, and I had to purchase an entire new G2 caliper.

Wheel out......must.......squeeze..............lever........ :D

Since you leave your bike parked with the wheel out, either make sure that you have a multi tool or screwdriver with you all the time, or put some kind of spacer in when you park the bike.

The pads are not actually getting locked together. It is just that the caliper pistons are extending out past their normal range. On most disc brakes there is really nothing (sometimes the seal do a little) that pulls the pistons back in. They just release pressure. If you extend the pistons too far they just stay out. So, you are not really forcing the pads apart, you are just pushing the pistons back in.

Thanks a million to you all for your responses. I really appreciate your help!

Wheel out......must.......squeeze..............lever........ :D

I have some little plastic gizmos from Hayes that are designed to fit between the brake pads when you remove a wheel. Sometimes the handiest solution is to prevent the problem in the first place.

I have some little plastic gizmos from Hayes that are designed to fit between the brake pads when you remove a wheel. Sometimes the handiest solution is to prevent the problem in the first place.
Those are handy when dealing with kids or morons. :D
Both of which are prime candidates for being brake squeezers