[slim]

i am a new rider and i have a cb450 k6 and the front brake keeps freezing up while riding, so i cant rid it anymore untell i get the problem fixed. if anyone might give me advice i would be very happy

 

[Psyco Diver 69]

assuming this is a disc brake front end it can be a bad caliper, bad master cylinder, or warped disc. If you don't have a disc brake front end then we need to know if its a drum brake set up and wether its hydaulic or cable operated

22/m
1980 Honda CB750
1972 Oldsmobile 442

 

[slim]

its a disk brake front end

 

[kenessex]

2 problems. 1 sticking piston and 2 sticking caliper pivot.
First remove the 3 bolts that hold the whole brake assembly on the fork leg and pull the 2 bolts from the caliper to take it off the bracket. Don't forget the stupid adjuster screw and spring. Next drive the pivot pin out of the bracket and clean all the corrosion off of it and lube up the pin and bracket with some grease( white lithium or any other medium viscosity grease). Next pump the piston out of the caliper with the brake lever. May need to add brake fluid to the resevoir to get the piston all the way out. Then remove the square section o-ring piston seal from the caliper. If you are careful you can get it out without damaging it and reuse it. Then get a small bent pick and clean all the corrosion and crystalized brakefluid out of the groove. Reassemble with clean fluid and you should be good to go. I would make sure you have the mastercylinder cleaned up good while you are at it. I neve replaace that little adjuster screw and spring on these. They will self center fine if the caliper is free to retract its piston and pivot freely. The spring just masks problems. While you are at it you might as well pull the disk and deglaze it too. A properly set up Honda front brake of this early style will work adequately. A poorly maintained one will lock up, drag and generally be dangerous.

Ken

AHRMA 412
Vintage racing - old guys on old bikes

 

[kenessex]

2 problems. 1 sticking piston and 2 sticking caliper pivot.
First remove the 3 bolts that hold the whole brake assembly on the fork leg and pull the 2 bolts from the caliper to take it off the bracket. Don't forget the stupid adjuster screw and spring. Next drive the pivot pin out of the bracket and clean all the corrosion off of it and lube up the pin and bracket with some grease( white lithium or any other medium viscosity grease). Next pump the piston out of the caliper with the brake lever. May need to add brake fluid to the resevoir to get the piston all the way out. Then remove the square section o-ring piston seal from the caliper. If you are careful you can get it out without damaging it and reuse it. Then get a small bent pick and clean all the corrosion and crystalized brakefluid out of the groove. Reassemble with clean fluid and you should be good to go. I would make sure you have the mastercylinder cleaned up good while you are at it. I neve replaace that little adjuster screw and spring on these. They will self center fine if the caliper is free to retract its piston and pivot freely. The spring just masks problems. While you are at it you might as well pull the disk and deglaze it too. A properly set up Honda front brake of this early style will work adequately. A poorly maintained one will lock up, drag and generally be dangerous.

Ken

AHRMA 412
Vintage racing - old guys on old bikes

 

[krapfever]

What Ken said. Twice.

If the brake is locked and you can't roll it,whack the caliper with a mallet or dead blow hammer a couple of times. This shoild loosen the pads a little. Not a fix but it will let you roll the bike/remove the caliper.

Honda go sideways!

 

[JB]

i will add that you should use brake cleaner while cleaning. i've had some problems with other "types of cleaners" i.e. carb cleaners and engine foam cleaners.

also, when putting your brake back together make sure that you prime every part of the brake system. for that you start at the lever, and keep working your way down the system with your finger on the line's end (airtight) and pump fluid through. make sure you bleed the thing when done.

CB650, FauxCatiFT500

 

[mikeo]

Another possibility that I've encountered on a 550 disk on a 360 race bike is a wedge shaped brake pad. It happens if you use the brake hard a lot. The caliper is not very strong and will flex and wear the pad unevenly. If you let it go long enough the pad will jam in the caliper (piston side) and hang up. I would just remove the pads and file them back so they were even again and use them till the next time it hung up.

Mike O.