Caliper piston removal

I see a lot of questions about it, and different methods for doing it...

I always just took the caliper off the supports, removed the pads and pumped the pedal/lever until the piston popped out. Yeah, you gotta make sure you don't empty the master cylinder in the process, or you'll have a lotta air to chase later.

Why all the different bench methods? Just curious.

 

Your method assumes the master cylinder works and the hoses are good. That isn't always the case.

 

I tried that method with the rear brake on mine. Unfortunately the rear master cylinder had failed AND there was a lot of rusting on the pistons. Ended up using compressed air to remove and then understood why people said be careful using this method ......... did the job though.

 

The reason I couldn't use the "master cylinder" method to force out my pistons, is that the brake pads were nearly impossible to get off while the caliper was still on the bike. I have a very stiff retaining pin on both front calipers that has to come most of the way out to remove pads. In fact I had to buy a "new" caliper because one just wouldn't come out(even after I drilled it all the way through, tried heat, penetrating oil, easy outs, etc) So if you have the caliper off the bike to take pads off, putting it back on and bleeding the whole system to get enough pressure to pump the piston out(twice in my case) is too big of a hassle.

I had the guy who sold me the caliper take out the piston on that one(he used a master cylinder he has for just that purpose. And on the one I had managed to get the pads off, I used Polock's "steam cannon" method. Exciting, but I can't in good conscience recommend it, there's a slight chance of caliper exploding like a pipe bomb. But the gist is, you put maybe a teaspoon of water in the caliper, seal it, put it in a vise, piston aimed at something you don't mind losing, and heat with a torch until live steam blows that sucker out. This is a "last ditch" type measure, I feel.

 

Sounds like more fun than a coconut in a $5 garage sale microwave

 

Oh, it was fun all right I tried really hard to get video of it, haha. Twice I attached my phone to my bike aimed at what I was doing on the bench. Both times I stopped heating too soon. (I thought the water was leaking out, turns out I stopped too soon) I have video of me pulling the hot piston out of a box with a Coleman air mattress in it Here: https://www.dropbox.com/s/fub5mzzwucxno ... -12-05.mp4

 

The easiest way to remove a caliber piston is with air. Have a blow gun with a rubber tip insert tip against the fitting and apply a shot of air it should come right out.

 

Shouldn't a grease gun do it? I mean, even the smallest hand grease gun can generate 3k psi pressure... Just get the $11 banjo fitment from chacal, and voila.

 

Yep, it would, if you have one, that's the preferred technique. The question was "why not use the master cylinder" There are a couple reasons, like not wanting to get brake fluid everywhere. I didn't have compressed air, or the right fitting, or a grease gun, that's why I did it the crazy way. As for buying a fitting from chacal, I just don't have the patience to wait days for something I can do now in another way.

 

you will not get fiuld everywhere. you drain the caliber for about 5-10 min and then apply air. but since you don't have air i have used anything that you could store air in and press the air out fast. a intube a 2 letter soda bottle. anything you can make a good seal and have a good amount of air.

 

Again, talking about using the MASTER CYLINDER, not air. Air is one of the bench methods. The question was, and I quote "why all the different bench methods?"

But, for the record, I personally don't think the air method is better than using a grease gun. But again, not the point.

 

My fault will shut up.... Need to read before I open my mouth all the way

 

Haha, no problem. I was just trying to clarify, I do the same thing all the time, sometimes these threads have so many posts