Brake pistons - need help!

[FunkyTime]

Hi all<br><br>I got myself a set of steel hoses for the 'Ace <!--EZCODE EMOTICON START :banana --><img src=http://img.photobucket.com/albums/v209/ ... ananna.gif ALT=":banana"><!--EZCODE EMOTICON END--> as I reckon that it is due for a bit of cheering up. Nothing wrong with the old brakes but well, you know...<br><br>So, off comes the r/h caliper and I can only get one of the pistons out. And, I noticed, when squeezing the pistons out onto a big spanner (wrench) only one of the pistons was moving. Looks like you get used to the performance gradually declining. 3 of them are crudded up. Looks like the 'friendly' dealer has just touched them up with some copperslip to make it look good.<br><br>So, it's time for a good strip down - might do the calipers whilst i'm at it! Last time I did this was on a GSXR and you could split the caliper. On a YZF, not so. Dodgy colour brake fluid as well - this job is well overdue<br><br>So, my question is, does anyone have a 'works-very-time' for getting the pistons out without having to resort to using loads of brake fluid?<br><br>Thanks all - in advance<br><br>FT <p></p><i></i>

[Peppa2]

I have the only lot of break fluid option in my mind and rubbing the brak pistons and and using silicone based lube's to get em to move againe,.<!--EZCODE EMOTICON START :hi --><img src=http://img.photobucket.com/albums/v209/ ... Waving.gif ALT=":hi"><!--EZCODE EMOTICON END--> <p>1990 Fzr 1000<br>Norway <!--EZCODE IMAGE START--><img src="http://i4.photobucket.com/albums/y102/P ... <!--EZCODE IMAGE END--><br></p><i></i>

[KontoBoy]

I'm told compressed air is the way to go. But I'll tell you I had some frozen rear calipers and 125 PSI wouldn't get them out.<br><br>If they are that frozen it may mot be worth a rebuild.<br><br>Kontoboy <p></p><i></i>

[ExupElvis]

<!--EZCODE QUOTE START--><blockquote><strong><em>Quote:</em></strong><hr>So, my question is, does anyone have a 'works-very-time' for getting the pistons out without having to resort to using loads of brake fluid?<hr></blockquote><!--EZCODE QUOTE END--><br> Cut a wood block about 2/3 as thick as the combined thickness of a new set of brake pads. <br> It should be roughly the same dimentions as the pads so that it will fit in the caliper.<br> Use compressed air to move the pistons while holding the block inside the caliper body. Carefull of your eye's, some brake fluid will spray when using the air.<br> Experiment with different positions (side to side) to free up the pistons. It will probably take a bit of working if they're stuck badly.<br> CAUTION: <br> <!--EZCODE ITALIC START--><em>DO NOT GET YOUR FINGERS BETWEEN THE BLOCK AND CALIPER BODY WHEN USING COMPRESSED AIR. IT WILL HURT.</em><!--EZCODE ITALIC END--><br> I had to replace all of my brake caliper seals a few years ago, now I take off the calipers and free them up every so often. Just did it this week again, they will stay in pretty good shape if regularly maintained.<br> Changing the fluid every two years isn't a bad idea either, but the pistons need to be freed up regardless. <br> <p><!--EZCODE FONT START--><span style="color:blue;font-family:times new roman;font-size:small;">Genisx1AtYahooeyDotCommaMomma</span><!--EZCODE FONT END--></p><i>Edited by: <A HREF=http://p072.ezboard.com/bexupbrotherhoo ... upElvis</A> at: 7/12/05 9:49 pm<br></i>

[F5]

When I used compressed air I wrap the calliper in rags to stop the pistons flying out too dam fast. If you need silly pressure then it gets too dangerous. <br><br>Usually the callipers are connected to the system & you can just pump them out to almost out & use blocks to hold them there, I use a mini sash clamp to hold one if required & push them back in (use caution, only when piston clean & use fingers to start it off). <br><br>A grease gun will hydraulic the pistons out at low pressure, but is mondo messy.<br><br>Whenever I take the pistons out of an older bike, heck even newish ones, I always find sludge hiding behind the pistons.<br><br> <p></p><i></i>

[FunkyTime]

Thanks all<br><br>This is the board to be on! All I need now is some compressed air. I take it that there is some sort of adaptor or the end of the hose screws in...<br><br>I shall take it to the guy who looks after my cars - he's got a full workshop including a compressor.<br><br>Thanks all, I shall let you know how I get on.<br><br>FT <p></p><i></i>

[F5]

With the amount of totally cheap compressors out there from Taiwan or wherever it is so cheap to buy one, if you have a garage you’ll wonder how you did without one. <br><br>The lowest spec compressor will run a tire pump & a dust blower, which is great for blowing dirt out of carbs or even drying your bike. Just use the blower & a bit of rag in the banjo bolt hole, this will seal it enough 90% of the time. <br><br>Keeping the pressure down with a bad seal is a good idea to slow the pucks down a bit. <p></p><i></i>

[FunkyTime]

And they sell them at my favourite store - Cost-Co!<br><br>As I am in the process of building a new garage, I might fit one in! Goood idea!<br><br>And I've always wanted to use this one<!--EZCODE EMOTICON START :pistol --><img src=http://img.photobucket.com/albums/v209/ ... pistol.gif ALT=":pistol"><!--EZCODE EMOTICON END--> <br><br>FT <p></p><i></i>

[FunkyTime]

Now I've got a problem.<br><br>One of the pistons is seized in the caliper - I can get them all out apart from one. Any ideas?<br><br>FT <p></p><i></i>

[creed12r]

<br> Clean the caliper and the pistons you can get out and re-assemble with new seals, clamp/hold in these 3 pistons, bleed the caliper and then pump out the remaining piston, clean this piston and the caliper again reassemble, bleed.<br> voila!<br> chris <p></p><i></i>

[FunkyTime]

I'll give it a go, chris, but it looks pretty solid to me! I'll let you know.<br><br>FT <p></p><i></i>

[cromwelluk]

Just serviced my calipers and yes air does work. but not if one is siezed and yes use rag or you get covered in oil<br>the only way to get it to moving was to user 2 levers back to back inside the pots and work it free I used a combination of different levers. pry bars and even ring spanners to get a good grip as they are different size pots not easy but once they move ( try a twisting action ) you are almost there.<br>you will need to remove the rubber seals and clean the groove's in the calipers as they build up with crap and cause the initial problem.<br><br>Then it just a problem to bleed the brakes which has and still is a problem on my bike.<br><br>Crommie<br> <p></p><i></i>

[750muppet]

It must be the weather for brake jobs.... I just did mine 96 750 and I can't believe what a difference new seals make, my brakes now have feel and are progressive. Spend up and do the job properly Regs Steve <p></p><i></i>

[ChuckD]

If you need to rebuild, it may be easier to cut a set of used R1 calipers. The last time I rebuilt a set of YZF 750 calipers, it cost more time, money , and hardache then a $40 set of used R1 Gold Calipers. <br>CHUCK D. <p></p><i></i>

[koma]

Just a tip for anyone attempting to get a seized piston out of a caliper...
I had an absolute nightmare of a job getting 6 seized pistons (of a total of 8) out of an '91 FZR250 3LN-3. I ended up taking the first caliper into a car brake specialist to see if they could get it unstuck - they failed.

The trick to getting it out turned out not to be blunt force (although it helps!) but to identify which way the piston has rotated and bound within the housing. If you can find which corner it sticking up slightly more than the others, using any means you've got force it back down, the very slowly pump the caliper whilst still hooked up to the brake system to get the piston to come out straight.

This took me 2 full days to release the 6 stuck pistons, but once it was done i had brakes like no other 250cc bike on the road!

[Stig]

To release the piston, try using a 'G' cramp and wrap it around the outside of the caliper body and then onto the outer edge of the piston. Tighten the cramp, making sure that its pulling square-on. Moving the piston further in sometimes breaks the seal and lets you then remove it easier

also works on seized bolts....turn them in further to break the seize....and then back out

hope you have some luck