Front brake dragging

My front brake is dragging pretty bad. If I lift the front wheel and try to turn it, there is considerable resistance. Wheel won't free spin at all.

I removed the caliper to check the bearings and with the caliper off, the wheel free spins.

The front brake system has fresh fluid, was bled out recently, no air in the system at all.
Could this just be a case of a dirty caliper piston?
Anyone else have this issue?

Also, when I Colortuned the engine, the ambient outside air temp was 40 degrees, will I have to lean it out a little when the temp increases to say around 80 degrees?

Thanks

 

It could very well be the piston. A master cylinder rebuild may also be needed if squeezing the brake lever brings a mushy feeling. But if the brakes are working fine except for releasing then I would clean the piston and use a thin wire to clear the backbleed hole in the bottom of the master clyinder.

As long as the engine was at operating temp then no.

 

Thanks Blue,

BTW- when i colortuned, ended up with 4 turns out on the screws and then gave an extra 1/2 turn for good measure.

Is 4 turns about normal for these engines? It seems like I have read that 3.5 is about normal.

Thanks

 

Hey Tony, I don't know if the 550 is like the XJ650, but I had the same problem and found that the pivot pin that the caliper is retained by had lost all of its lubrication and this prevented the caliper from "floating" freely on the rotor. So I greased it up---inside and out with moly grease and some sprinkles of graphite, too---and re-torqued to proper specs and no more dragging!

 

Chacal, Excellent suggestion, never thought of that.
I'm going to work on this issue this weekend, I'll let you know what I come up with.
Thanks

 

My XJ700 used to adjust to 4 turns as well.
I have since made a modification and now I have to turn them in to about 2 turns.

 

If you got the caliper off without a fight I'll bet this is your problem. A stuck caliper would be hard to pull off the rotor.

 

Yup, Just tore into the front caliper and the piston is corroded and the seals are boogered up too. Corrosion all around the seal races and on the piston.
I'm not sure either is fixable.
I might be able to replace the seals BUT I'm not sure I want to do that then rely on this brake after all this. Are there aftermarket calipers available for these bikes?
The Mastercylinder is good. Lines are good too.

 

There is a very good chance you just need to do some maintenance.

You need to pull the whole caliper with it's mount and clean-out the cylinder that the caliper travels on.

The outer Dust Cover protects the Traveling Bushing. The Traveling Bushing employs O-Rings for seals and smooth the travel.

Non waterproof grease gets contaminated affecting this entire area making essential movement difficult and rebounding impossible.

Overhaul the expansion area; complete. Clean the parts with Brake Kleen. Use ScotchBrite's or 800 to clean the Cylinder. Twist thin strips of ScotchBrite. Roll -- tightly -- 800 ... or, "Tie-wrap" to a slender plastic tool and get after the housing cylinder. (Bic Pen)

Remove O-rings from small bushing-piston. Clean. Remove surface imperfections; complete. Shine. "Shoe-shine" to a near polished surface. 800 - 1000 - 1200 if needed. Put cleaned O-rings back on.

Lube and reassemble.

Use nothing but the highest quality waterproof grease sold at high-line bicycle stores. (Or ask for a sample)
One tub is enough for you, your son and grandson to enjoy for the years to come ... even if your son isn't born yet!

Wipe the cylinder with waterproof grease. Add a couple drops of Marvel Oil to the Cylinder. Smear the Piston and O-rings very lightly with waterproof and replace the Piston. Exercise the parts together. Once reassembled; the Mount should travel along the piston. Too much grease will "Air-lock" the travel movement.

A slight smear and a drop of oil will help prevent total pressure and vacuum lock. If it's acting like it's locking when you are assembling it; try to work-out the bubble. Reduce grease if necessary.

You can paint the mounts Porsche Brake Red while they're off. Hobby Shops stock miniature rattle-cans with just enough for two coats of one mount.

 

I've decided to replace the piston and seals together. Mainly because of my series of "unfortunate events" involving the piston.
I think I'll have more piece of mind also since the now damaged piston was corroded pretty bad anyhow.
BTW, after the unfortunate event involving the caliper piston, it took a good 40 yard flight into oblivion. -That'll teach it !

 

You didn't recycle it? Tony! Of course I understand the 40 yard hurl got a lot of steam out, but part of me cringes at the thought of a piece of recyclable material being wasted. Do the green thing man, give it a proper burial.