Failed at changing brake pads. Need your help!

[Duddy]

Today I tried to change my rear brake pads. I got up to the point where I took out the old pads (there were actually no pads on them whatsoever, they just now started to grind so that's why I jumped on this ASAP). I am new to motorcycles and don't know completely what I'm doing (as you'll be able to tell from this post). When I took the old break pads off, I couldn't fit the new pads in because of the pistons were to close to each other in the calipers. I tried with all my strength, and was careful not to damage the pistons, to open them enough to slide the new pads in.

Well, I'm going off what the manual says. It says that it may be necessary to open the master cylinder reservoir and diaphragm (What is that?) to remove some fluid. It says if they cylinders are difficult to push back, attach a clear hose to the bleed valve and open the valve up and try again.

So what I did is open the master cylinder reservoir and unscrewed the two bleed valves. Brake fluid spewed out and I cleaned it up with a rag. After trying to move the pistons after that, they still didn't budge. So I bled some more and tapped the break while doing this. This shot out fluid and made the pistons even closer together! I didn't know what I was doing (obviously).

Now this is where I'm at currently - I am low in brake fluid due to all the bleeding (I don't even think I bled it right??), the pistons are shut closed, and the brake pedal bottoms out.

I don't know what I did, but I thought you guys could help me out. Is this something that I could fix or should I take it to the shop stealership?

Thank you in advance!!

[Wild-Bill]

Wow, that must have been fun to watch!

OK, here's what you do. First of all, grab some soap and water and wash that brake fluid off everywhere it got to. It dissolves paint.

Right, now to business. Drape some towels around so you don't have to wash everything again until you're done and open the bleeder screws on the caliper. (Just unscrew them half a turn or so.) Now you're going to have to get something in between the caliper pistons to pry them apart. A putty knife may be your best bet at this point. Pry a little from the top, a little from the bottom, back and forth. You don't want to get those pistons jammed up by getting them cockeyed on their cylinders.

Once you've moved the pistons enough, slide the old brake pads back in there to give yourself something you don't care about to pry against. Keep going until the pistons on both sides are all the way down to the tops of their cylinders. No point in half measures here, is there?

Once the pistons are retracted all the way close both bleeder valves, clean everything up and install the new pads. Don't forget to clean up the pins the pads slide on. After the pads are installed you fill up the master cylinder reservoir, pump the brake pedal up and down to refill the line and cylinders (Keep an eye on the fluid level while you do this.) and start bleeding the air out, starting with the bleeder closest to the wheel.

Oh, if there's no way to get anything in between the pistons, even with the bleeder valves open you can pull the caliper off the bike and separate the halves. That's two bolts. There's an o-ring between them that you'll want to replace if you do this so plan on making a run to the hardware store for that. Get the halves separated and you shouldn't have any trouble at all using a C-clamp and one of the old brake pads to push the pistons back into the cylinders.

[Kreylyn]

It is possible the seals on the pistons are damaged, or the pistons are dirty and causing it to be very difficult for them to be pushed back in.

You may need to consider a rebuild kit for the caliper. It's not that hard, it's not that expensive, and it replaces the parts that wear and tear anyways.

Krey

[expvet]

+1 on the C clamp idea. It lets you gently push the pistons back enough to open up for the new pads to fit in. You only need enough room to fit over the disk, so the pistons really do not have to travel very far in. Put a folded rag or something to prevent the clamp from scratching the outside of the caliper. You might want to consider a Katana Haynes repair manual, they show you how to do almost everything and have a lot of pictures of the procedures. They are a good $30.00 investment.

[wismo]

Ihavent done bike pads yet but on cars i use a c clamp and the old pad to press against to compess caliper

[rexazz2]

I rebuilt BGs fronts for her last summer
Multi piston calipers are a PIA if everything is not in perfect condition and clean
I put a piece of wood between the pistons and some compressed air to get the pistons out and retain my fingers

[Duddy]

Thanks guys. I bought some brake cleaner and will try to clean around the pistons. I'll see if I can scrounge up a c clamp.

[JayBell]

failing that, try the putty knife to try and spread the pistons enough so you cna get something bigger in there.

tip for the future: spread the pistons out first before ya remove the old pads. This goes for front or back calipers. I myself generally use a piece of flat barstock and a crescent wrench to turn the pistons back open.


heres hoping the pistons didn;t go out too far,

[newkatbie]

use the old pads and some slow hard pressure on the pads with a clamp. That should work if your pistons are not stuck. At least you tried to do it yourself. Props.

[rexazz2]

BTW the service manual is available in the Katana wiki

[Wild-Bill]

...use a piece of flat barstock and a crescent wrench to turn the pistons back open...,

Crescent wrench... Why didn't I think of that? I've just been man-handing it all these years. :headslap: (I use a big-azzed screwdriver and turn it.)

[Duddy]

And now the plot thickens...

I took the caliper off and finally got the pistons to seat all the way back. Installed the new pads. I started to bleed the bleed screw closest to the wheel. I bled that around 10 times. I don't know for sure if there were bubbles still in there because I was using a black hose. Well, I tried rolling the wheel and it wouldn't turn. The pads where completely compressed against the rotary (?). So the wheel is stuck and the brake peddle just drops to the bottom without moving the caliper/ pads. I only bled the one bleeder deal, not the other too. I don't understand. I bled it according to the manual.

I don't know if the pistons even moved or not (they don't really look like they did). When I first put the pads in, the wheel spun fine. I made sure to keep brake fluid in the reservoir.

You probably remember from my first post that I emptied most of the brake fluid via bleeding. Well, it wasn't bleeding the right way. Basically all I did was push all of it out so now there are air bubbles all over the place.

Should I bleed both bleeder valves the right way?

What should be my next step?

[Malarky112]

Call a buddy or a mechanic over who knows what they are doing!

Sorry, I know thats not helpful, and I dig you trying to do stuff yourself, but its clear you don't have a clue and brakes are not something you want to be guessing on.

Just my 2 cents, I am sure these other guys will be more helpful then me.

Good luck, stay safe.

[Wild-Bill]

Don't worry about what those calipers are doing for now. Just focus on getting fluid back into the system. Things should start working right again once you get the system full.

Get yourself some clear tubing while you're at it or you'll never know if the air is out of the lines or not. If you want to make the job a lot quicker and easier hit Wal-Mart for a vacuum pump. (~$10 IIRC) It'll come with some of that clear tubing you need and you use it to pull the brake fluid into the calipers instead of trying to push it with the MC.

[Duddy]

Thank you, Bill. Your help is greatly appreciated. I'll buy the vacuum pump at Wal-Mart. I'll check in once all fluid is back in with no bubbles.

Would there be a chance that I need a rebuild kit? I didn't separate the calipers, I just took the whole caliper off so that I could have a better angle at sliding the pistons back in.

Thanks again.