2004 electra glide classic front brakes locking up.tried another master cylinder and replaced fluid with new.what else could be causing it.
By "locked up", I'm assuming that once you release the front brake lever, the bike will not roll. As with all disc brakes, the brake pads do not withdraw away from the disc. They maintain light pressure on the disc to keep it clean and dry. When you pull the lever, they apply stopping force. When you relaese the lever the force is releaved but the pads still stay in contact with disc lightly and the wheel will turn.
If you've tired another master cylinder and the brakes are still locking up, there is something wrong with either the hose or the caliper itself. Usually, it's the caliper. You must take the caliper off and use compressed air to get the piston out. You must be very careful while doing this. If you must use high air pressure, the piston will come out of the caliper with extreme force. I use a small air pressure regulator to slowly increase the pressure starting at about five psi.
If you get to 25 psi or better, things can get dangerous. At this point, I quit using air pressure and go to a grease gun. By taking the end off the end of the hose on the grease gun, it will screw right into the place where the brake line goes most of the time. Now pump the grease in until the piston pops out. It's a nasty job but a lot safer than the air pressure method. Clean the caliper up completely free of grease. Use a wheel cylinder hone to hone the inside of the caliper's piston bore. Pay particular attention to the groove where the caliper top seal goes in. Lubritcate the piston and the inside of the piston bore of the caliper with the proper type of clean brake fluid and press the piston into the bore. The caliper is now ready to reinstall. Make sure you are using the proper type of brake fluid. Harley changed back to DOT 4 brake fluid but I can't remember what year. It should be on the top of the master cylinder cover. Do not mix DOT4 and DOT 5.
I have on a few occasions seen a rubber brake hose that would not allow the brekes to release. They get damaged on the inside. The very high pressure present when you apply the brakes can get past an obstrucion on the inside of the hose. But, once you release the pressure, as the pressure lowers, it gets to a point where it cannot get past the obstruction and thus holds this amount of pressure on the caliper. Replace the brake hose.
Make sure you bleed all the air out of the system. If you leave any in there, as the air heats up, it expands and applies pressure to the brakes and makes them drag. Alweys test the brakes before riidng the bike. Improperly serviced brakes can cause serious injury or death. Good Luck, Steve
Apr 25, 2010 |
2004 Harley Davidson FLHT - FLHTI Electra...