Urgent Help Needed - Brake Job Screwup

[Raydr]

I'm doing my first bit of work on my bike and I've already screwed it up.

I'm replacing my back brake pads. It was going well enough until did something dumb...

I removed the left brake pad (the one closest to left side of the bike), then went to remove the right. In order to remove it easier I pushed the round thing in (the round thing that pushes the pad) which made the other side come out more. I go to insert the new pads and realized that I couldn't on the left side because that circle thing was too far out.

No matter how much pressure I put on it, I cannot get the darn thing to go back in. I've tried prying as hard as I could with two screwdrivers and nothing. I opened up the bleed valve to let fluid out and nothing. This is my first time attempting this and I have no idea what else to do.

Please, please help? Thanks!

[DerekNC]

Mine was extremely hard to push back in as well. If you've got a c-clamp you can pull the caliper off the disk and use it to push the piston back in. At least I think that's what I did as it's been awhile. 

[Raydr]

I am willing to give that a try...but I worry that it was so easy for it to come out, but so difficult to get back in. I hope it didn't seize.

I was thinking maybe there was a "release" or something I was missing...

Any other thoughts?

[FearedGS500]

yea hes right its gonna be hard. get your old brake pad and put it in there as far as you can(that way you dont mess up the brake pistion (circle thing as you called it )) . and use the c-clap and try to get it back in .. its best if you can take it off the bike and do it that way .. it should be like doing car brakes ( if you have done that ) its easyest if you have the tool for it .. it makes things 10 times easier .. but yea its gonna be kinda of hard .....

[scratch]

Rear brake resivior cap needs to be removed to allow brake fluid to backflow from the caliper body; soak some of the fluid up so that it doesn't overflow.  I'm surprised that the bleeder valve didn't do the job for ya.  Make sure the piston is not askew in the bore.

[tussey]

Cool!! I didn't know you could replace the pads without removing the caliper from the rotor. NEAT! I'm gonna have to try this. 

[scratch]

You sure can!  The difficult part is just what he is experiencing, pushing the pistons back in to make room for the thicker, new pads.

[ixolas]

Did you removed the break line or clamp it already?  If not, put a small vice grip on the rubber line brake line,  remove the bango bolt holding the brake line on, and then you can take the caliper and work on it on a workbench.  Make sure the piston (large cylinder thing) is square (or completely in line) in the opening and if so you should be able to push it in with your thumbs or a moderate amount of force with some wide channel locks (if you don't have these you can get a cheap set at walmart).  If you can't push it in then: it is either not square and you've really jammed it up, or you have one of the inner gaskets caught in it's path; hopefully its the first.  Try pulling it out, alternating sides, because if it wasn't square and you pushed in on it really hard, you've really wedged it in there and you'll have to get it loose again. If you can't do this you're going to have to take the caliper apart.  Don't worry, it isn't that bad and all you need is new gaskets, but hopefully you can get it loose without rebuilding it.  One thing to remember is not to get mad, its a learning experience; i bet you'll never do it again.   
I hope this helps and I hope that you get it fixed without having to take the caliper apart.

[annguyen1981]

Cool!! I didn't know you could replace the pads without removing the caliper from the rotor. NEAT! I'm gonna have to try this. 

What is best?  removing the caliper or not?

[scratch]

Not.

[scratch]

Did you removed the break line or clamp it already?  If not, put a small vice grip on the rubber line brake line,  remove the bango bolt holding the brake line on, and then you can take the caliper and work on it on a workbench.  Make sure the piston (large cylinder thing) is square (or completely in line) in the opening and if so you should be able to push it in with your thumbs or a moderate amount of force with some wide channel locks (if you don't have these you can get a cheap set at walmart).  If you can't push it in then: it is either not square and you've really jammed it up, or you have one of the inner gaskets caught in it's path; hopefully its the first.  Try pulling it out, alternating sides, because if it wasn't square and you pushed in on it really hard, you've really wedged it in there and you'll have to get it loose again. If you can't do this you're going to have to take the caliper apart.  Don't worry, it isn't that bad and all you need is new gaskets, but hopefully you can get it loose without rebuilding it.  One thing to remember is not to get mad, its a learning experience.

What would be easier would be to pump the brake pedal, that will unwedge the piston since you can't 'pull' on it.

[coll0412]

Bad idea, to much pressure and now your caliper is clamped to your rotor, just pull of the caliper of the bracket and be done

[scratch]

Not true.  Have you ever pumped (one pump) your brake?  The piston moves very little, as that is all that is needed for it to move across that little space between the pad and rotor.

Another thing that you can do to prevent that, would be to put the old pad in there with the screwdriver so you can pry it back apart.

[The Buddha]

OK the old pads are tinner, and you have the pistons out enough to accomodate just that thickness. With thicker pads, its gonna have to get back in further.
I have broken C clamps pushing them in ... so its not easy or loose or whatever. BTW the pistons need to be clean and lightly lubed and pretty smooth before pushing them back in ... else they will rip the seals. Its an idea to do the seals once in a while as well. Every pad mabe about right - 10K for front and 25K for rear is what I get. Usually.
Now you have opened the bleed screw. You have to properly get all the air out.
Cool.
Srinath.

[Chuck]

Not true.  Have you ever pumped (one pump) your brake?  The piston moves very little, as that is all that is needed for it to move across that little space between the pad and rotor.

Another thing that you can do to prevent that, would be to put the old pad in there with the screwdriver so you can pry it back apart.

That's what I always do.  Since the old pad is trash it doesn't matter if you jam a screwdriver in there.

[Raydr]

Okay, so here's what happened.

It was pitch dark outside so I moved the van around and put the headlights on my bike so I could continue working. I removed the bolt that holds the exhaust pipe/muffer up, then pried it away from the bike a little so I could get my socket wrench on to the caliper bolts.

I removed the brake line from the caliper, then I was able to get the 2 bottom bolts loose, but not the top right one (it's attached to an arm of some sort...). No matter what I did I couldn't get that one loose, but it's okay because I can still lift the caliper off of the rotor.

I pull it up and now I have almost full access to the caliper. I decide to try and push in the piston that way, and it's still jammed. I tap the thing a few times and suddenly now the piston smoothly slides in for me. Great!

I reassemble the brake, put everything back together and it looks awesome. I now know how to do a quick and easy REAR brake job (tonight I'll attempt the front brakes...). I understand where it went wrong and know how to fix it now.

Then I go to push the exhaust pipe in to place to get the bolt back in, but I guess I messed with it too much because I could not, for the life of me, get the holes to line up. I literally spent more time trying to get that damned bolt in then I did working on the brakes. I'm still hurting today from it...I ended up finally getting the bolt in BACKWARDS (with the nut on the outside) and am going to let it stay like that for a week or to so that the heat will "bend" the pipes back in to place...

I bled ALL of the fluid out while I was trying to push the piston back in, so I jump on the bike (front brakes only), run to Walgreens and buy some DOT4 (surprisingly they had it...), ride back home and follow the instructions for bleeding. I then spent the next 10 minutes driving down my street and locking up the back tire to test it... (I also like to do this occasionally to "program" myself to control the bike naturally if I ever have to lock up my brakes on the road, in traffic...)

Everything worked out and so far I'm happy I was able to do this myself.

Next up: Front Brakes! I thinking they might be easier since there's less stuff in the way but...we'll see.

[Chuck]

When you do the front, don't remove the brake line from the caliper.  If you can at all avoid getting air into the front brake system you'll be much happier and safer.  The only reason I would remove the brake line is replacing it with a new one.

[ixolas]

I agree.. you really don't want to remove the line or get air into it to much.  I would, unbolt the caliper
clamp closed the break line (vise grips)
open bleeder valve
using old pads, put a screw driver or pry bar between them to spread out the pistons
close bleeder valve
replace pads
bolt back up
un-clamp brake line
then bleed the front a little to ensure no air got back in there.

I'm not trying to be condescending or rude, just trying to help you with the steps to do a quick pad change.  Hope your front replacement is easier than the back.

[Chuck]

You can compress the caliper without opening the bleeder, or vise gripping your brake line.  The fluid will go back into the reservoir.

[sledge]

Vice-grips on a flexible brake line??  . A good tip is to slide a couple of large sockets over the jaws of the clamps, then clamp the line between them. The polished and rounded sides of the sockets are far less likely to cause damage to the line than the serrated jaws of the clamps.