caliper mount process

[Randy Grein]

Nope. The most important thing is to get the calipers/pads parallel to  
the rotors. There seems to be a fair bit of slop in the caliper  
mounts; if those mount bolts are loose the pads, and by extension  
calipers should line up with the rotors. Another way of looking at it  
is that the 'immobile' parts really aren't immobile at all. I use this  
process routinely to snug up the brakes and have zero problems.

I was talking with Dan Zlock today about many things engine related -  
one of which was the 'immobile' nature of engines. We like to think of  
that big, beefy crank being infinitely stiff, cases likewise, but they  
really do move around quite a bit. At speed the crank flexes all over,  
the main bearing bosses elongate with each engine revolution, walking  
the main bearings into the crank. Seems they never walk away, but  
always to the center because of the way the crank flexes.

Randy Grein, WMRRA #41

On May 27, 2008, at 12:23 PM, matthew patton wrote:

> I think Randy said:
>
>> If all that works put the bike on stands, loosen the caliper bolts,
>> spin the wheel a few times tapping the brakes then clamp down.
> Tighten
>> the caliper bolts. This seems to align the calipers to the rotors,
>> reduces drag and gives much better feel.
>
> This seems wrong to me. If you tighten the pads/pistons first then you
> end up applying a twisting force to the rotor and the pistons+pads are
> now out of kilter wrt to the rotor when you tighten the calipers
> against the immovable fork leg. Shouldn't all "immobile" parts be  
> tight
> before adjusting those that are designed to move/flex?
>
> Aside from the rotor cleaning/reconditioning steps mentioned I've  
> found
> that sometimes getting the air out of the brake lines can be a
> bugger-all task. And other times I get it done within a few minutes.
> Once I'm reasonably sure the lines are clear, I'll barely loosen the  
> MC
> banjo with the system under pressure and let it weep and retighten
> before removing pressure. I've been surprised at how much air was  
> still
> in the junctions.
>
>
>