Topic: 1978 CB550 Front Brake

[yellowjacket]

I am struggling with getting my front brake adjusted.  I bled the brake and tried to adjust following the directions of the manual.  The issue is, when I squeeze the brake and release there is still pressure on the pads not allowing the wheel to turn freely.  I have no leaks in the system.  What do I do next?

[flybox1]

Did you check the caliper piston/piston seal?
Could be issues in there causing the piston to not ride properly on the seal.
Did you service your MC piston/seal/bore, and that tiny return hole in the cup?
Old cruddy fluid can prevent fluid return.

[yellowjacket]

No to all of those.  I will check those all thanks.  Do you know of a link were I could watch some one do this?

[flybox1]

might be something in these vids by Dino

http://hackaweek.com/hacks/?p=1797
http://hackaweek.com/hacks/?p=1795

[DaveBarbier]

Is this sound? If you squeeze the brake lever and the wheel is locked that means the piston is not retracting. If you were to crack the bleeder and fluid shoots out, that means that the MC return hole is blocked.

Does that test hold water? I'm thinking if the piston seal wasn't springing back, the fluid pressure behind it still can go back to the MC once you release the lever, so fluid wouldn't squirt out the bleeder. Correct?

[Farley121]

Just a shot in the dark, is your caliper mounting arm adjusted properly?  Could be your inboard pad rubbing.

[redrider736]

might be something in these vids by Dino

http://hackaweek.com/hacks/?p=1797
http://hackaweek.com/hacks/?p=1795

+1 Hackaweek vids are full of great info....

[yellowjacket]

I took the front brake off to inspect it. It was full of grime.  I knew the piston was suppose to come out but could not figure out how to get it out.  While holding the brake in hand I squeezed the front brake until the piston virtually fell out in my hand.  Inside the cylinder was some nasty looking snotty stuff.  Cleaned it out.  Looked for the reported small return hole and could not see it.  Where is the return hole?

[Kenzo]

The "return hole" is located at the master on the handle bars. It just relieves the pressure applied by the master cylinder.

There is no mechanism to actually retract the piston/brake pads at the rotor. The system basically ends up with a clap when you apply the brakes and drag(pads floating on the disk) when you release the brake lever. Some drag is normal.

Cheers

[robvangulik]

Be sure to clean the seal and the groove it lives in very thoroughly, and make sure that hole (there are 2, one of those very small) in the bottom of the master cylinder is clean too.

[yellowjacket]

I got brakes now.  Thanks guys for the help.  Waiting for my tank, side covers, fenders to get painted. Got my seat and hoop the other day from harisuluv, the seat looks awesome.  Should be riding soon.