Freeing Brake Bobbins

Fred W · Feb 27, 2015

A couple of random thoughts about this proposed maintenance:

One, when you put the bolt and nut on the bobbin, do not over tighten it or you may squish the sides of the spool inwards and change that dimension, making it harder to float.

Two, I would not spin the bobbin too fast as you may wear that interface. You want it to be clean and movable, but not sloppy and floppy. If your 3/8 driver will run at a slow rpm it may be OK, but not if it spins it fast.

Performing preventive maintenance on your bike should strive for the same standards as a doctor: Primum non nocere!

lonerider · Feb 27, 2015

Fred W said:
A couple of random thoughts about this proposed maintenance:
One, when you put the bolt and nut on the bobbin, do not over tighten it or you may squish the sides of the spool inwards and change that dimension, making it harder to float.

Two, I would not spin the bobbin too fast as you may wear that interface. You want it to be clean and movable, but not sloppy and floppy. If your 3/8 driver will run at a slow rpm it may be OK, but not if it spins it fast.

Performing preventive maintenance on your bike should strive for the same standards as a doctor: Primum non nocere!

Considering the vibration the impact will impart on the bolt, with a continuous jet of air directed at the edge of the bobbin, it shouldn't require much movement to clear any debris out. My impact is air powered; I can regulate the air pressure for the desired speed. I'd certainly hope the bobbins' metal isn't so soft that a maximum 75 ft lb. of torque would deform it, though I'll be sure to watch for that. If any problems arise doing it that way, I'll be sure to post on this thread.

hppants · Feb 28, 2015

This is what I figured regarding inner pad wear. The pins are always dirty. Every time I take my front wheel off, I clean them up, but it comes back often. My pistons are not stuck - I'm not the only one that is experiencing this issue.

stealth1 · Feb 28, 2015

You gotta figure if Yamaha spent the extra bucks to use floating discs, it can't be a good thing when they stop floating.

Canadian FJR · Mar 1, 2015

"

You gotta figure if Yamaha spent the extra bucks to use floating discs, it can't be a good thing when they stop floating."

This is one of the wiser comments I heard on this forum.

audiowize · Mar 1, 2015

hppants said:
This is what I figured regarding inner pad wear. The pins are always dirty. Every time I take my front wheel off, I clean them up, but it comes back often. My pistons are not stuck - I'm not the only one that is experiencing this issue.

I found on my '03 that one pad on the left side was wearing way down while the other pad looked new. I rebuilt the calipers, and sure enough, the dust seals were starting to come apart and had seized up a couple of the pistons.

When you're in there, go ahead and clean out the bobbins anyway.

rogdeb · Mar 2, 2015

Canadian FJR said:
"You gotta figure if Yamaha spent the extra bucks to use floating discs, it can't be a good thing when they stop floating."

This is one of the wiser comments I heard on this forum.

+ 1

Freed up the bobbins on mine yesterday. They were all seized ! Unlike in the original "how to" video though, I can't turn them by hand ! At least I know they're free of gunk and probably will act as they're supposed to under braking operation.

Canadian FJR · Mar 9, 2015

Did my front last night. None of the bobbins (buttons) were seized but the do move better now.

Not a big job but one of those little piece of mind ones.

Canadian FJR

bluesdog · Mar 9, 2015

Why isn't this procedure mentioned in the FSM? Or is it, and I missed it?

I mean, I think it's cool, and being somewhat OCD I'll probably do it to my feej, but I'd like to hear from a brake maintenance expert about the practical value.

The FSM has some pretty absurd stuff already, such as requiring removal of the throttle bodies if the rad needs repairing, or taking off the entire fairing when servicing the front forks, so I'm a little surprised there isn't an official, overly complex procedure for the disc spools.

jeremyr62 · Mar 9, 2015

The fact that the bobbins aren't loose/don't spin doesn't mean they are not functioning. If you are going to check them, you really need to check them when the disc is hot, not stone cold. The disc will expand when hot away from the bobbin. This is the function of the bobbin/rivet. The disc is not clamped tight. Thermal expansion of the rotor will expand the rotor ID out. If the disc were clamped tight you would run a bigger risk of distorting/cracking the disc.I really doubt this kind of maintenance is necessary myself.

Freeing Brake Bobbins

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