cailper piston removal

Ok I've rebuilt the master cylinder and cleaned it completely, even a new sight glass that is liquid tight.

I'm on the caliper rebuild but the caliper is winning. I cannot get the piston out! I've read a pretty good post here about removal and I'm working my way down the list using what I have at my disposal. I have tried air pressure and I've rebuilt the a shorted version of the brake system hoping the fluid would push it out. I've assembled the rebuilt MC and one of the old brake lines because my SS are not here yet.

The piston worked before I started all this so I'm guessing it isn't locked in place but so far no movement. It's rediculously hard to tell if I've bled the system right (which is normal from what I've read).

Do you think once bled all the way it should move? Am I really wasting time and I should just go get a grease gun? What kind of gun do I really need?

 

I cheat...

To get the pistons out of my 3 XJ1100 calipers I removed the caliper from the bike, left the fluid in and then with the caliper free & pads off, I pumped the brake & added fluid as it went down. That forced the pistons right out of the calipers.

So I lost a little fluid... It did the job perfectly & fast.

Maybe you have some air in the line to be bled? Till that's gone the piston won't budge much.

 

Yes. Unless you'd like to try Dave's steam-powered-knock-a-hole-in-the-ceiling method.

I would also suggest:

Roll of shop towels
Spray can of brake parts cleaner
Q-tips
Can of brake fluid (best thing I have found to get brake parts sparkling clean)

 

I did the same, just pump your brake lever till it pops out.
Add oil as needed.

I was having problems bleeding the brakes.

This is what I did, just took a clear 1/4 hose "ID"(3' long)
And sucked the air out (yes with my mouth), take as much air out as you can.
Plug the end of hose with your thumb and pump your lever.

Im not a pro, but hell it worked.

 

Oh ya I forgot to mention I will not be trying the steam meathod

 

A lot of people have great success by putting a grease fitting in the bleeder hole and using a grease gun to push the piston out. The grease gun will force a crazy amount of pressure in, will force grease around the the cylinder via hydraulic pressure, and help loosen and remove the cylinder. It also does not "pop" the piston across the room as compressed air is wont to do.

Dave fox

 

Don't forget the solid bolt to block off the banjo bolt hole, otherwise grease will just squeeze out there.

 

i figured that was obvious But, yeah, I probably should've mentioed it.....thanks, tskaz,

dave

 

Sometimes the most obvious is the most overlooked.

You know, kinda like when you unhook the bottle after a sync, just to realize you forgot to pinch the line off.

Or you can't figure out why that damn starter button won't work, then realize that not only did you forget to turn the key, you also forgot to put it in the ignition switch to begin with.

:lol: :lol: :lol:

 

quickest way is to pumb brake fluid through it till it pops off, make sure to catch it so you dont damage the piston... you might waste a bit of brake fluid but it does the job simple enough, ive just had to rebuild both my calipers and i found that was the easiest way, you coul also try shocking it gently with a rubber mallet so it frees up

 

The "grease gun" method works every time, and other than wasting a few ounces of grease, has no real drawbacks (except for not being dangerous or exciting.)

Your basic, lever-type hand-operated grease gun http://www.northerntool.com/shop/tools/ ... 5455_55455 is all you need, nothing fancy. The link is for illustration only, you can pick one up at pretty much any auto parts store (or Sears) for under $20.

The bleed screw is shaped like a 'zirk' fitting, you can simply engage the grease gun's nozzle. Plus, as above, block the union hole with a solid bolt.

 

* Update
I win! the piston is out! Thanks for all the help.

After switching to a grease gun and letting some penatrating oil soak over night it's out. Now for the cleaning and rebuilding.

 

I use a rubber tip air nozzle but also do the unthinkable....split the calipers.

Hold the caliper half face down....you want the piston going DOWNWARD on a block of wood with some sort of cushion under the piston (a piece of rubber works well and seals the passage holes)

Press down on the caliper half, making sure your thumb or finger tips aren't under the piston, and trigger small amounts of air in the banjo hole till the piston pops.

DISCLAIMER...If you do not understand this process completely, don't try it serious injury can result!!

EDIT: The Yamaha service manual specifically states the calipers should never be split!