1977 honda cb750a brake problems?

Question

When i press the brake (front brake) it stays tight to the rotor and wont release. I have changed the brake pads, changed the brake fluid, removed, cleaned and inspected the piston. Any ideas?

Answer 1

i would try a diferent brake hose . sometimes they get old and collapse inside .

Answer 2

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Answer 3

Check the sensers they might be broken if not you should go to the machanic

Answer 4

should bleed brake lines to get all air out

Answer 5

The hose certainly could be swelled on the inside and isn't letting the fluid return.  Try this, apply the brake firmly, let up on the lever and then crack open the bleeder s***w.  Be careful that it doesn't squirt all over the place.  If it's under very high pressure, then the problem is in the master cylinder on the handlebar or the hose.  To determine which, pressure it up again and then loosen the banjo bolt at the master cylinder.  If it's under high pressure, then it's the master cylinder.  If not, it's the brake hose.  Be careful of spilling brake fluid onto painted surfaces, especially if your bike has the beautiful blue tank.  

If the bleeder s***w is not under high pressure, then the problem is the piston sticking.  When you removed the piston, did you make sure there was no corrosion on the piston or cylinder?  

Also make sure the caliper is adjusted correctly.  If memory serves me, you jack up the front wheel and loosed the locknut on the s***w on the caliper, turn the s***w until it starts to contact the disc and then back the s***w off 1/4 turn and tighten the locknut.  If the s***w it too tight, the piston can be backing off but the s***w is holding the opposing pad against the disc.

Answer 6

The caliper probably needs cleaned and new O-rings and dust caps installed. Sometimes years of oxidation behind them cause them to grip the piston.

Dismantle the calipers remove the dust cap and the O-rings.  Take a metal scribe and remove all the oxidation accumulated where the O-ring and dust cap fit.  Clean the inside of the caliper thoroughly and install new O-rings and dust caps