H2C Front Brake Binding/Jammed

[Nigel Thorpe]

Hi all. Bike has not been out recently, just moved around the garage but have noticed that it was heavy to push around. Turned out it was the front brake jamming on. Single front disc and caliper - all standard original. Master cylinder is aftermarket. First thing I noticed was a lot of slop/movement of the brake lever before it started moving the master cylinder piston - is this normal with aftermarket masters??
Now down to the disc and caliper. The bracket between the fork lugs and the caliper 'appeared ' hard up against the disc. There is a small mark where the paint has been rubbed off of the back of the bracket. Removed the caliper, after letting some fluid go, and all appears OK. Piston free and bracket slides on caliper bolts. Anyone any experience of this? And could someone please let me know what their clearance is between the disc and the back of the caliper bracket.
Thank you
Nigel

[skub]

Can you post up a pic?

[Triple Parts]

The aftermarket master cylinders behave exactly the same as original.
Have you fitted new pads recently? The EBC pads are quite thick and can cause some binding issues in some cases. Removing some pad material helps.

[Nigel Thorpe]

OK thanks both for response.
Tried to get a decent photo but almost impossible to get a good shot.
I had been looking down on the caliper to fork leg from above and now realise that, in way of the disc, the back of the bracket is relieved to give clearance to the disc. So the bracket not an issue. This morning, took the caliper off, split it and fitted the bracket by itself - wheel/disc rotates freely and I can see the clearance front and back. So why was the binding occurring? No new or EBC pads.
As I understand it, with the pistons, when brake is applied then let go the seal(s) distort and pull the pad/piston back slightly, to allow free running, so this wasn't happening. As mentioned the bracket slid in the caliper OK. I don't know. The bike hasn't been out for ages, I was just moving it around the garage and using the brake. Maybe everything needed a good clean.
Change of direction but I have been thinking about going for the zpower double disc conversion - does anyone have any experience of that kit?? Or ar ethere other options out there.
Thank you
Nigel

[Triple Parts]

If the pads aren't returning, you could have a blocked bleed in the Master cylinder.
In the bottom of the MC there are two small holes that allow air and fluid to pass between the brake fluid reservoir and the cylinder. If they are blocked they won't release pressure and allow the piston to return.

[Nigel Thorpe]

Hi. Yes checked the master cylinder holes as clear. Fluid looked clean/clear. I tried to simulate pressure release by draining some fluid from the caliper bleed nipple, which made no difference - disc still tight on pads. There was no sudden release of pressure. Took the caliper off, moving the pads clear a touch by twisting the caliper slightly after loosening fork lugs bolts, which moved the piston pad back a touch and allowed removal.
Thanks

[Wolfie]

If the pads aren't returning, you could have a blocked bleed in the Master cylinder.
In the bottom of the MC there are two small holes that allow air and fluid to pass between the brake fluid reservoir and the cylinder. If they are blocked they won't release pressure and allow the piston to return.

#2

[BIG H]

The thick pad must be a loose fit in the bracket.
The bracket is fixed to the fork leg & does not move, which means the pad must move freely.

[Nigel Thorpe]

OK thanks. Wheel away being rebuilt and going double disc so will check pad movement when I get it back together.