[GlennF]

Hi,

I have a 2011 B% and lately there is a loudish squeak/clunk from the front brakes but it only occurs at the point the bike comes to a full stop.  I even get this noise when pushing the bike and applying the brakes. Braking while riding is perfectly normal it only happens as the bike comes to a full stop.

Anyone had this issue, or any thoughts ?

[Guaire]

Hi Glenn F - your caliper's piston may be popping back out of its seat at that time. Sometimes the pistons get really sticky. I have a 2011 B5 myself. Each piston has a rubber seal ring around it. After 13 years it might be time for a brake job! The pistons are probably still perfect, but 13 years is a long time for rubber piston seals.
I was having to bop my front caliper with a hide mallet to get it to release. Hitchcock's suppled me with fresh pads and seals.
I had a terrible time getting one piston to release its seat in the caliper. I ended up using a plumber's tool! It's little ferruled concentric wheels that expand and grip the inside of the piston ---- like a plumber turning a pipe.
For fluid I send the fluid up from the bottom. After it's full, sealed and bled, I put a big rubber band on the front brake lever. This gets any air bubbles up to the reservoir.

[axman88]

For fluid I send the fluid up from the bottom. After it's full, sealed and bled, I put a big rubber band on the front brake lever. This gets any air bubbles up to the reservoir.

Thanks for the interesting tip!  I also have been bleeding moto brake lines by injecting fluid from the bottom.

What does the rubber band do to help the air move?  Is there a valve that is opened by squeezing the lever, or is this just a matter of holding pressure on the system which makes the air more motivated?

[Guaire]

axman88 - When the front brake lever is is pulled in, the reservoir of fluid is open to the fluid in the brake line. Overnight the tiny air bubbles will rise by gravity to the reservoir. Then you can check the fluid/reservoir level in the window. It probably won't need a fill up. Pumping fluid up from the bottom is very efficient. Still, there are tiny bubbles.
 
That's how I have an aged 2011 Bullet with a front brake that feels like showroom, not antique-y! Thanks to the light weight of a Bullet, the single disc has plenty of stopping power. Also, there's a payoff in weight loss as you have tossed your stock silencer for a custom one. That probably threw away around 20 pounds.

[Haggis]

Think you got confused.
When the lever is pulled the piston moves forward past the hole that allows fluid into the line.
This is how it compresses the fuid to actuate the calliper.
The reservoir is not open to the brake line.
I think the myth about tieing the lever back is that it compresses the smaller air bubbles and when the pressure is taken off they somehow make bigger bubbles or disappear?  No idea as cannot see how it would help in any way?

[Haggis]

Here is the master cylinder with the piston position superimposed.
Brake off, both fluid ports open.
Brake on only the larger piston lube port is open.
The front seal moves past the feed hole sealing the brake line off from the master cylinder.

[axman88]

it compresses the smaller air bubbles and when the pressure is taken off they somehow make bigger bubbles or disappear?  No idea as cannot see how it would help in any way?

Perhaps making the air bubbles smaller, reduces the surface area of the air in contact with stationary surfaces of the tubing and equipment, and those surfaces become wetted, so when pressure is released bubbles have less adhesion to surfaces and are more easily shed?

[GlennF]

Well I was hoping there was a solution that did not involve disassembly and bleeding the brakes but it what it is, thanks for the advice.

[Haggis]

Your squeak when you come to a halt is probably just your pads on the disc. Take them out a give the a clean. Make sure the calliper can slide freely on its sliding pins. You can exercise the pistons by pushing the calliper in towards the wheel, this will push the pistons back into the calliper. Then pump them back out with the lever. Do it two or three time to make sure they are moving freely.
As for the clunky noise.
Play in the steering head races  or wear on the fork slders are your likely source.

[Bexley55]

To fix the noise from your front brakes, try cleaning the pads, making sure the caliper moves smoothly, and pushing the pistons back into place. Also, check for any wobbling in the front wheel or wear on the fork.