Brake pistons touching rotor - Cant push them back in.

inferno

Well-known member
Was trying to change rear brakes, and there wasnt enough space to put the new brakes in.
Thought if i press and release the brakes and push it, id be able to make enough space. Big mistake, now the pistons are touching the rotors. Any idea how i can push them back in without bleeding the brake lines?

I tried pushing it back but it didnt erally budge..maybe 1 or 2 mm

Here is a pic for the lulz


The bike is a 89 Katana 600

Thanks :)
 
Take the reservoir cap off. Take the bolts off the caliper and gently rock the caliper back and forth and the pistons should move back in enough to get the caliper off. Just watch the fluid level in the reservoir that it doesn't overflow as the pistons go back in the fluid level will rise.
 
what do you mean exactly by rocking the caliper back and forth. should I take off the calipers to push the pistons in. and will that work for the piston on the opposite side of the rotor?

Thanks
 
If the cups are pushed tight against the rotor you won't be able to pull it off. Rocking it back and forth will push the cups in enough so you can remove the calipers. Once removed, use a pair of channel lock (adjustable) pliers to slowly squeeze the pistons back in one at a time.

Actually before pushing them back in use some brake or soap and water to clean the grime and crap off of the cups. A little maintenance never hurts :)

Squeeze them in, install new pads, pump the pedal until you have brakes and you're good to go!
 
sweet. i managed to make a little bit of space between the piston and the rotor.
Gonna try to take the calipers off tonight.
Dont think anybody ever changed the brakes :@
 
sweet. i managed to make a little bit of space between the piston and the rotor.
Gonna try to take the calipers off tonight.
Dont think anybody ever changed the brakes :@

You have a little metal on metal contact there, what does your rotor look like?
 
that looks like a caliper who's slide pins are seized. Remove the pins, clean the rust and lube em up.
 
I don't need to see the pins, the pad wear is evidence enough. When caliper slide pins are seized, the pulling action on the inboard pad doesn't occur. So the outboard pad now does all the braking and the other pad just sits there, never being pressed against the rotor.
 
I don't need to see the pins, the pad wear is evidence enough. When caliper slide pins are seized, the pulling action on the inboard pad doesn't occur. So the outboard pad now does all the braking and the other pad just sits there, never being pressed against the rotor.

You do realize he posted a picture of one used pad beside a new pad? His pads arent actually wearing that uneven...Also I dont think you realize his caliper is 2 piston non sliding caliper, not a 1 piston sliding caliper where what you are saying normally happens...I run the same caliper on one of my bikes

With this type of caliper is possible for a piston to get stuck, causing uneven pad wear...But from his first picture its clear that both are coming out evenly as they are both contacting the rotor....
 
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Carefull rocking the caliper back and forth rotors can bend pretty easy.
 
I don't need to see the pins, the pad wear is evidence enough. When caliper slide pins are seized, the pulling action on the inboard pad doesn't occur. So the outboard pad now does all the braking and the other pad just sits there, never being pressed against the rotor.

I believe the picture is old vs new and you are seeing it as outside vs inside.
 
Thank you Rob, will make note of that. It does require a thorough cleaning.

The rotor was rubbed a little but but luckily i found out as soon as that happened so there isnt any damage on it. Just some rust rubbed on to it. Ill post a pic once i get home.
Cheers.
 
I thought the photo was of the pads he removed from the bike, not new vs. old .... Carry on!
 


So much for an easy change job.:@ After struggling for 2 hour thats all i managed. Barely enough space to squeeze the old pads in. The only thing i couldnt do was take the calipers off. I couldnt even budge the bolts..Swollen hands didnt help either :@

Will anybody with more experience with be able to help me out? Or else i think i barely made enough space for the bike to be rolled up a tow truck :S I am located around don mills.

I WILL do a better job with the front brakes!
 
reason you're not having any luck pushing them back in is that most likely you are only pushing on one side of the caliper cup cocking it. You have to press the cup back in evenly for it to go. I dont think you'll have any more luck without removing the caliper....that should be your priority one. Allen wrench with a pole on it for more leverage, it will let go.
 
So much for an easy change job.:@ After struggling for 2 hour thats all i managed. Barely enough space to squeeze the old pads in. The only thing i couldnt do was take the calipers off. I couldnt even budge the bolts..Swollen hands didnt help either :@

Will anybody with more experience with be able to help me out? Or else i think i barely made enough space for the bike to be rolled up a tow truck :S I am located around don mills.

I WILL do a better job with the front brakes!

I can't believe no one has mentioned this already...

Step 1) Use short bursts on an impact gun to loosen the caliper bolts, then pull it away the rotor,
Step 2) Attach a tube to the brake bleeder nipple, put the other end in a container
Step 3) Loosen the brake bleeder valve
Step 4) Use small C-clamps and the old pads to evenly squeeze each piston back into the caliper body
Step 5) Re-install caliper with the new pads & top up your brake fluid

The pistons will retract MUCH easier with the bleeder open. If that doesn't work then you may have a seized caliper, which has to be either rebuilt or replaced. You may be able to leave the caliper in place and replace the pads but I don't know your bike to know if that's possible.

Last point - resist the urge to just put a cheater bar on your allen wrench as a way to apply more leverage, you'll risk shearing the bolt or worse, bending the caliper mount. You really need an impact gun to take it off. If you don't have access to an impact gun and are close to Ajax I may be able to help you. Lemme know.

Cheers,
Daryl
 
I ended up taking it to Rosey where after 30 min they were able to make enough clearance to put the new pads in. They thought it was seized also but they managed make enough room.

If the offer still stands, I might take you up on it when the time comes to change my front brakes. And from the sounds of it, it might take too long.

Cheers.
 

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