clarification on front brake piston

[Anonymous]

I have read a few things that seem to conflict and would like some clarification.

I have been having problems with my front brakes holding and not releasing. I cleaned the relief valve (lots of sediment), but still have problems. I was going to take apart the front calipers and clean out behind the piston. I can imagine that there would be lots of junk there. I have also read that the O ring channel may be filled up with gunk pushing the O ring out on the piston, and binding the piston wherever it may be.

My question is about removing the piston. I have read that to remove it you can use the brake fluid to pop it out while the caliper is removed from the bike, but still atttached to the brake line. To do this you just pump the brake. I have also read never to pump the brake handle when the caliper is not installed on the bike, but the break line is still connected.

So can I remove the caliper piston by simply pumping the brake while caliper is not installed, but still attached to the brake line? Or will this cause damage? Thanks.

[Hap Call]

You can remove the piston that way without damage to anything in the brake system. The reason they say don't pump the brakes with the caliper off is because most people will be only changing their brake pads and having the pistons pop out would not be something they would want.

Hap

[Anonymous]

Brake Piston

Hello U can use compressed air once u remove the caliper from the bike. BUT use low pressure it will come out with some force but no damage will occur if ur carfull. The O ring may B damaged causing the piston to bind. If u must clean up the piston surfaces U can use 1500-2000 grit water sandpaper using oil in place of water, This wil restor them to new condition. Remember to lube the caliper with brake fluide when installing the piston.
Best of luck! Archei

[Anonymous]

pump away

The reason it's said not to pump the handle while the caliper is removed is so you don't unintentionally pop out the piston. it's the best way to remove it. Be sure to have a container handy to catch the fluid, once the piston pops out of the bore it'll start running.
You can use air but you have to be careful the piston doesn't fly out.
Whatever you use to clean things out make sure it's compatale with the seals, use the wrong chemicals and you're up the creak.
A friend of mine worked at Canadian Tire and a car lord of kids came in complaining their brakes were not right. Upon further questioning he found out they had used engine oil instead of brake fluid. When he took the top off the master cylinder the rubber gasket looked like a stringy lump of snot. Ended up replacing all the rubber components of the system.....Mike

[Anonymous]

Brake Piston

Hello U can use compressed air once u remove the caliper from the bike. BUT use low pressure it will come out with some force but no damage will occur if ur carfull. The O ring may B damaged causing the piston to bind. If u must clean up the piston surfaces U can use 1500-2000 grit water sandpaper using oil in place of water, This wil restor them to new condition. Remember to lube the caliper with brake fluide when installing the piston.
Best of luck! Archei

[Anonymous]

Brake Piston

Hello U can use compressed air once u remove the caliper from the bike. BUT use low pressure it will come out with some force but no damage will occur if ur carfull. The O ring may B damaged causing the piston to bind. If u must clean up the piston surfaces U can use 1500-2000 grit water sandpaper using oil in place of water, This wil restor them to new condition. Remember to lube the caliper with brake fluide when installing the piston.
Best of luck! Archei

[Anonymous]

Brake Piston

Hello U can use compressed air once u remove the caliper from the bike. BUT use low pressure it will come out with some force but no damage will occur if ur carfull. The O ring may B damaged causing the piston to bind. If u must clean up the piston surfaces U can use 1500-2000 grit water sandpaper using oil in place of water, This wil restor them to new condition. Remember to lube the caliper with brake fluide when installing the piston.
Best of luck! Archei

[Hap Call]

Can you say that one more time Archie?

Hap

[KEITH KRAUSE]

brehill, be very careful if you use an abrasive to clean up the piston or the bore. On a typical bike like my 1000, the service wear limit is (-) or in other words, the piston and bore must remain their original sizes. Don't even remove .001" For light cleaning, you might want to try Blue Magic or Semi-chrome polishing paste. This works well for polishing carb slides and bodies. I think the pistons will just pump out, but I've always used compressed air. Be sure to use a rag so the piston can't hit anything and get scratched.
If you have the chromed caliper axle bolts, corrosion of the chrome plating can cause the calipers to not slide back and forth smoothly. They also have o-rings and need a special grease, according to Suzuki.