Stuck brake piston in calliper - how to remove

[ukjules]

I have a stuck brake piston on my gs550e.

for some reason I simply cannot find any info on how to unstick / remove the piston even
though there is a thread of the same name as mine ?
There is no advice on the thread and it simply says - thanks for the advice ?

Does anyone know the methods of how to unstick a piston so I can restore the calliper ?
It is currently soaked in wd40 in readniess.

Thanks so much in advance .............

[GateKeeper]

You can use compressed air to remove it, be careful, once it releases and pops out, it will come out with great force, an alternative is to add a grease nipple to the caliper and using a grease gun pump grease in to move the caliper out

[Sandy]

Find a bolt to plug the banjo bolt hole, remove the bleeder and try some compressed air. If it's really stubborn I've heard you might be able to use a grease gun on the bleeder and pump grease into it, just be prepared when it lets go, it could be messy. I've never had to do it but you may have swap a grease fitting for the bleeder.

[qisteve]

First, if you use compressed air be VERY careful! That piston WILL fly out like a bullet. I lost the tip of my thumb to a caliper piston that shot out. If it's not too stuck, fill the caliper with penetrating oil and let it soak. Afterwards, try pulling it out by twisting with pliers. If it still won't budge, you can often adapt a metric grease (Zerk) fitting to the hose inlet and pump it up with grease. The grease will fill the caliper and force the piston out very slowly. If you have to go to that length, however, the caliper is probably in really poor condition and may need replacement. Good luck!

[Wingsconsin]

Find 2 paint sticks and use them as a spacer to "catch" the piston cup as it is forced out. The sticks are just wide enough to stop it from flying out and causing damage - it hits the sticks just before it pops out .

Use compressed air to blow it out - watch your fingers getting pinched will hurt - grease guns also work but then you have to clean all the grease out - a messy job.

I have had some luck with getting pistons unstuck by using a large c-clamp and forcing the piston back IN by a mm or two.
The movement breaks the stuck seal and then it came move outward again... In and Out carefully will work - soaking will help -
Patience and persistence are your new allies.

Imagine the paint stick across the outer legs where the black plate is in this picture -inside the calipers -

[Crankthat]

All great advice above!
Have never tried the grease but have read that it works.
Have done the air trick.
The compressed air is messy.
Good to note that brake fluid will rust things when exposed to moisture.
Including moisture in air.
Unknown how long it takes.
Will strip paint also!
Just saying be careful for your spray as well.

I have had a few stuck while taking apart for rebuild before.
Good to note that if it cocks a bit while removing it will become difficult to get out.
It is not only rust that can cause this problem.
You may have a bit of luck pushing it back in a bit and then taking out if this is the case.


Link to overhaul calipers from BassCliffs website.

Take note of using the 1/2 inch thick piece of wood.
Could save you a bit of trouble next time around.

[Crankthat]

I really like your piston pusher Wingsconsin.
That is slick!
Will have to make one myself!

[ukjules]

Thanks all ! Brill advice.

Will try pushing it back in a bit first as have no access to compressed air bar a diving cylinder at 230bar !

[2BRacing]

I always remove the caliper, but leave the brake hose connected. After removing the brake pads, just squeeze the lever or pedal to pump the piston out. Be careful not to spill brake fluid on any paintwork etc.

[JTGS850GL]

I always remove the caliper, but leave the brake hose connected. After removing the brake pads, just squeeze the lever or pedal to pump the piston out. Be careful not to spill brake fluid on any paintwork etc.

That's what I've done. Why reinvent the wheel when you already have the means to press the piston out using what Suzuki designed.

[ukjules]

You have just answered my next question ..

I have pushed them back in with a g clamp - they moved which is good.
Thing is now they are right in and need to come out.
I will simply reconnect brake hoses and press the brake pedal and out they should come.

As you say I should not have removed them entirely ..

Thanks for help

[GateKeeper]

;have brake fluid available, and keep topping up the reservoir....if you pump slowly enough you won't need to put the cap on, just keep adding fluid....once it releases, have rags around to soak up the fluid make sure you keep it away from painted parts you don't want damaged

[Grimly]

I always remove the caliper, but leave the brake hose connected. After removing the brake pads, just squeeze the lever or pedal to pump the piston out. Be careful not to spill brake fluid on any paintwork etc.

With a couple of old master cylinders lying around and a surfeit of knackered old hoses, I'm inclined to make a bench-top rig to do just that for calipers that are already off. It will also provide a useful outlet for bled brake fluid that would otherwise be discarded.

[GregT]

For the sake of complete coverage if anyone searches this topic I'll add a bit.

If you have a completely seized piston in your caliper, removal is best done by drilling and tapping the visible face of the piston. You then use a long bolt wound in against the inner face of the caliper to forcibly remove the piston. Don't do this without sourcing a replacement piston first....

[2BRacing]

That's what I've done. Why reinvent the wheel when you already have the means to press the piston out using what Suzuki designed.

Exactly! The first time I needed to refresh the calipers, I read up beforehand and saw references to using compressed air. However, knowing myself and my luck (what luck?), it was a real possibility that I would end up with a compressed-air-generated spray of brake fluid all over the garage and my bike and cars! So I realised that just by using the hydraulic brake system that is already there, you can get the job done in a much more controlled and safer way!

The front calipers are easy because there is only the one piston in each, but the outer piston of the rear caliper tends to come out first, leaving the inner one still inside that part of the caliper. You have to "restrain" the outer piston slightly with a piece of wood or a "C" clamp, so that the two pistons move by approximately equal amounts until they are both nearly completely out. Then you separate the two caliper halves, and the pistons can easily be removed by hand.