Stuck Caliper Piston

[cummins2014]

Well here goes again , a leaking tire on the fifth wheel got all this started, while the tire was off thought I would pull the hub to see what size grease seals I would need to pack the bearings. What I discovered was a broken plastic dust cap, and worn out disc brakes. Bought the four new grease seals ,and 2 new sets of disc brake pads.

All went well on the first one ,packed the bearings ,changed the pads ,I put a clamp on the caliper piston to push it back to give me enough room to get the caliper back on , no problems . Proceded on the second one, got to the part where I clamp the piston back for more clearance, and it will absolutely not move, even put a cheater on the clamp no go. Never had a caliper piston before that couldn't be pushed back in . Anyone have any suggestions how to get that piston to release ??

[ferndaleflyer]

My F350 is sitting in the garage right now after a piston froze and ruined the whole mess. Got a new caliper and pads and something is not right as the wheel won't turn free. It was late so I'll figure it out tomorrow after I get back from getting new tires on my DP.

[przao]

I second the motion to replace the caliper. I like to RV on the Oregon coast, and often stay right next to the water. I drive a 1-ton Diesel and always applied the emergency brake. A couple of years ago the dealer had to replace all my calipers because the pistons all were rusted to the point where they would not properly retract - never had anything like that in half a century of driving all over the country. The mechanics asked me if I was from Canada with their salted roads! Now I am careful not to leave the truck parked too long with the parking brake applied to reduce the probability of rust building up.

[John_Joey]

I would replace the caliper. Very possible the piston has rust on it. If the seal doesn’t look perfect,then that’s the problem. Might be able to push it in, but it won’t be right.

[cummins2014]

Cummins12V98 wrote:
Clamping the edge for sure can cause the piston to bind.

And I’ve pushed in more pistons then I can count , and that was a first pushing on the edge and binding . I’ll for sure never give one a chance again .

[Cummins12V98]

Clamping the edge for sure can cause the piston to bind.

[opnspaces]

94-D2 beat me too it. I always use an old brake pad to both center the pistons as well as protect them from damage.

[Tvov]

94-D2 wrote:
I always use the old brake pad to center the pistons to push in. Works every time....

LOL! After all these years, I never thought of that. I always seem to search for a more complicated solution!

[94-D2]

I always use the old brake pad to center the pistons to push in. Works every time....

[cummins2014]

All's good , more operator error then anything. I usually use some adjustable welders clamps or just a C-clamp. Putting pressure just on one side of the piston, has always worked, not this time . Well google is a wonderful thing , placed a piece of 1/4" plate across the piston .and put on the c-clamp in the center, and it went right in like it should, no froze piston after all.
Learned something today. Although I did the axle behind like I usually do without a problem.

[cummins2014]

Home Skillet wrote:
Just replace the caliper.
A sticking caliper will make the pads drag, causing over heated brakes.

Or, loosen the bleeder screw while pushing the piston in.

Thanks. I'll see if the bleeder screw will let it go, that was my next move, but thought there might be other ideas , but leaning toward a new caliper.

[Home_Skillet]

Just replace the caliper.
A sticking caliper will make the pads drag, causing over heated brakes.

Or, loosen the bleeder screw while pushing the piston in.