need help with ATV brake installation

[corndogggy]

On my 250EX, I was having trouble with my brakes, as the piston in the caliper seemed like it wouldn't retract, so the front right brake was about locked up all the time. I clean the caliper real good and put penetrating oil around the piston. It seemed to be working ok so I put some new pads on. I tried to install the caliper but it won't fit. Basically the caliper's installed position makes the rotor hit the outside non-movable brake pad barely past the metal backing. It's like the installed position on the caliper is 1/8" or 1/4" off. The entire caliper needs to move over to the outside a little but I can't figure out how. Maybe my knuckle is bent, I have no idea. I know there are those bolts behind those rubber plugs that you can adjust but it's cranked all the way in. Any help would be appreciated, it's unridable right now.

As I was typing this, I realized that theoretically a caliper has to float a little, because one brake pad doesn't move, but as it gets worn down the entire caliper has to travel to the inside a little to keep the pads centered. Maybe this functionality or whatever is locked up and needs some penetrating oil? Seems like that would make sense.

[barney]

corndogggy; Put a c-clamp on the piston and retract it a little?

[carpenterguy]

corndogggy; Put a c-clamp on the piston and retract it a little?

what he said!!!! usually works just fine

[C.L.Button]

corndogggy; Put a c-clamp on the piston and retract it a little?

I'll third that ! Tighten the clamp JUST enough to slide it over the rotor. ;)

[corndogggy]

No, it's not the piston. I could open them up enough so that the rotor would go in between the pads. The problem was that once I did this, I couldn't bolt the caliper to the knuckle, it was too far away. If I did it backwards and attached one bolt of the caliper to the knuckle then tried to pivot the whole thing back to attach the other bolt, the outside brake pad would hit the rotor. No amount of clamping the piston would fix that because the outside brake pad doesn't move with the piston, it's fixed.

I messed with it for a long time after posting this then reading the piston clamping suggestions and found that there was a corroded bolt like I suspected. There are two different pieces of the caliper... the caliper itself, then the mounting plate. The caliper itself should be able to float back and forth along a big bolt that holds these two parts together. It's pretty much the same thing as a car. The problem was that this bolt was really corroded so it was permanently fixed to the 100% inward position. I hosed it down with penetrating oil then took a big set of pliers to make it move back and forth to break it loose. It's tons better now. It still rubs a little, but it's nothing like it was. Maybe I need to tear it back apart and actually grease that bolt instead of just using penetrating oil?

[C.L.Button]

Yep, take it back apart but do not use grease ! Use some "emory cloth" and lightly sand off the rust/corrosion, apply a light coat of "anti seize" and re-assemble everything. This is a good thing to do twice a year especially if you ride in alot of mud/water. ;)

[corndogggy]

Yep, take it back apart but do not use grease ! Use some "emory cloth" and lightly sand off the rust/corrosion, apply a light coat of "anti seize" and re-assemble everything.

I'm not sure what emory cloth is. Also, the anti-seize stuff, you're talking about that real thick metallic silver junk? I just wouldn't have thought to use that in this situation. I guess grease may have a good chance of contaminating the brake pads though.

I got this answer from a four wheeler racing board, sounds pretty much like the same answer:

"What it sounds like is your floating pins are jammed up. Those "bolts" under the rubber boots is what makes your caliper "float"
You have to pull apart the caliper mount and slide or remove the caliper from the pins and then lightly emery the pins and lube them up."

[C.L.Button]

I'm not sure what emory cloth is. Also, the anti-seize stuff, you're talking about that real thick metallic silver junk? I just wouldn't have thought to use that in this situation. I guess grease may have a good chance of contaminating the brake pads though.

I got this answer from a four wheeler racing board, sounds pretty much like the same answer:

"What it sounds like is your floating pins are jammed up. Those "bolts" under the rubber boots is what makes your caliper "float"
You have to pull apart the caliper mount and slide or remove the caliper from the pins and then lightly emery the pins and lube them up."

Emory cloth is a VERY fine sanding paper specifically for metal. Make sure you spray off the bolt with brake cleaner & wipe clean after lightly sanding.

The grease will contaminate the pads, because it is that the grease MELTS & RUNS from the brake heat. Anti Seize will not melt or run. ;)

Trust me baby ! :D

[carpenterguy]

tell him cl!!!! emory and antisieze the 2 best tools you can have for a successful brake job.. the grease will actually cause that pin to stick again after it becomes hot.. this in conjunction with the contamination of the pads makes for a sucky day of redo....lol good luck