350X Front Brake Caliper-Pistons are "stuck" in there

[patblkwell]

Well as luck would have it, the front brake system on the X I am restoring was the only thing in poor condition when I got the bike. I need to replace the reservoir and may have to replace the front caliper if I can't get the pistons to come out. I soaked them in some brake fluid and wd40, I even took an air hose and blew some air in there where the brake line goes(like the manual says to do), but they still haven't come out. Anyone ever dealt with this before?

[Howdy]

Yep, I took a new front master cylinder I had and hooked it up. Once I bled the air out the one piston came loose. Then I put a C-Clamp on the freed piston and the other popped loose.
Howdy

[jeswinehart]

I was gonna see if those was frozen but didn't so I could get it back to you.
Not that it matters really ,,, you are doing the same efforts as I would.
The caliper from my X was a PITA to get them broke free.
Keep your fingers clear is my best advice ,,, I was holding mine in one hand and using a rubber tipped blowgun (like you use for baloons ) and whem my stuck piston decided to pop out I thought for sure my finger was broke.

john

[thefox]

I know the trick that worked on some old motorcycle calipers for my brother. He threaded the end of his grease gun into the thread for the brake line and then pumped away. It used a bunch or grease and you have to be careful or it will get all over but it worked great.

[patblkwell]

Yeah I may have to try some different methods, I put some brake fluid in there then put the air hose to it but nothing yet. OH John, I got the left front fork from a buddy over here today, it had the brake caliper, reservoir, and the rare brake line guide still on it! I really got hooked up I guess you could say. The pistons are stuck on the other caliper too...I'm sure they'll eventually free up.

[Jason Hall]

Well this might sound wrong but it worked like a charm. I just got done getting a piston out of my 250-R calipar. I drilled into the piston about an 1/8", with a 5/16 drill bit. I then used a 3/8" bottoming tap & threaded it into the hole, & twisted the piston around in the bore about 3 times then clampped a set of vise grips onto the tap & twisted & pulled the piston rite out. When I was done I welded the hole up. The pistons in the R calipar's are extremely thick. So I had no chance of drilling through it. I don't know how thick a 350X piston is so I would use the drill & tap as a last resort.

[whiteman350x]

I don't even play with those pistons. I hook up my compressed air tank from my paintball gun to the line hole. Be sure you point it away from anything important!!!! I set the reg at 850 pounds and shoot the air to it. Be sure to have something soft for the piston to hit when it comes out. It helps to wear earplugs at this step - the resulting pop is very loud. Then I put a soild bolt in the line hole. I put an adapter I have fixed into the hole from the first piston and clamp it in with vice grips. I hook the air to this adapter and shoot the air to it. I have never seen a piston that can stand 850 pounds of air. They will come out!!!

[3leggeddog]

i have always heard to soak them in kerosene.don't know if it work though