Topic: Brake caliper swinger question

[buffalogt750]

I'm in the process of updating my front brake on my CB550. I've installed a Nissin 1/2 inch bore master cylinder and just got some semi-sintered EBC pads that I need to install and I've ordered a one piece braided stainless brake line. I also have a drilled rotor. I'll be using the brake light switch built into the new master cylinder. I'm curious about the caliper swinger and why it is spring loaded. I understand how to adjust it but it seems to me the spring does nothing but add some extra drag (although probably just a little) to the brake. All calipers float to allow for brake pad wear but I know of no other that uses a spring to pull the caliper against the rotor. If the spring is supposed to help retract the piston, isn't that the job of the caliper seal? Has anyone removed this spring? Can anyone tell me why it's even there?

[MCRider]

The spring positively pushes the B pad away from the disc by the amount of the adjustment, usually 5 thou or so. The A pad will gently slide on the disc making a shusch sound, but the B pad should be clear of the rotor.

The spring does not add drag. It postively makes sure there is less drag.

[flybox1]

the spring is there to keep the stationary pad OFF the rotor when the brake is not engaged.
It is to be gapped per the manual during tuneups, and when gapped properly, it will not drag.

yeah...what MC said 

[buffalogt750]

 I don't have a problem with the brake dragging (I guess I should have said I feel that the spring could theoretically add drag by pulling one of the pads against the rotor) and I know how to adjust the swinger and check it often but I was curious as to why this is the only spring loaded caliper around. Lots of other older bikes as well as a lot of cars have a single piston caliper with no spring to keep the stationary pad off the rotor, the piston side pad simply retracts and the caliper is self centering with equal contact of both pads on the rotor when brakes are released. It just seems like the spring positively keeps the stationary pad off the rotor at the expense of letting the moving pad drag on the rotor a little.

[MCRider]

I don't have a problem with the brake dragging (I guess I should have said I feel that the spring could theoretically add drag by pulling one of the pads against the rotor) and I know how to adjust the swinger and check it often but I was curious as to why this is the only spring loaded caliper around. Lots of other older bikes as well as a lot of cars have a single piston caliper with no spring to keep the stationary pad off the rotor, the piston side pad simply retracts and the caliper is self centering with equal contact of both pads on the rotor when brakes are released. It just seems like the spring positively keeps the stationary pad off the rotor at the expense of letting the moving pad drag on the rotor a little.

You're probably right. I'd just say this was the first disc brake ever on a production motorcycle, and one of the first ever on anything. So they had some trial and error in design to wade through. Properly adjusted it causes no problem.

IF it weren't there, and the rest of the design was unaltered, the A pad would keep moving into the caliper and the B pad clearance would get greater and greater until it takes 2 pumps of the lever to restore the clearance. This would be a dangerous condition in an emergency.

[754]

I always remove the springs, other say its not the best idea..
 Sure makes removing wheel on dual disc..alot more pleasant..

[buffalogt750]

IF it weren't there, and the rest of the design was unaltered, the A pad would keep moving into the caliper and the B pad clearance would get greater and greater until it takes 2 pumps of the lever to restore the clearance. This would be a dangerous condition in an emergency.
[/quote]
I don't understand why pad A would keep moving into the rotor without the spring. It seems to me the opposite would be true. Since the spring pulls pad A against the rotor, wouldn't this tension tend to push the piston into the caliper?

[MCRider]

IF it weren't there, and the rest of the design was unaltered, the A pad would keep moving into the caliper and the B pad clearance would get greater and greater until it takes 2 pumps of the lever to restore the clearance. This would be a dangerous condition in an emergency.

I don't understand why pad A would keep moving into the rotor without the spring. It seems to me the opposite would be true. Since the spring pulls pad A against the rotor, wouldn't this tension tend to push the piston into the caliper?
[/quote]
First line of your quote. I did say the A pad would move into the caliper not the rotor. You switched it on me.  Without the spring, the A pad will bang its way into the caliper from road irregularities. Believe me, people here have tried to run witout the spring and that's what happened. I ran one time with the spring way out of adjustment, and same result. Needed nearly 2 pulls on the lever to get the pads back where they should be.

With the spring AND the stop setting screw, the A pad retreats into the caliper but only as far as the stop screw wiill allow. 5-8 thou.

[MCRider]

IF it weren't there, and the rest of the design was unaltered, the A pad would keep moving into the caliper and the B pad clearance would get greater and greater until it takes 2 pumps of the lever to restore the clearance. This would be a dangerous condition in an emergency.

I don't understand why pad A would keep moving into the rotor without the spring. It seems to me the opposite would be true. Since the spring pulls pad A against the rotor, wouldn't this tension tend to push the piston into the caliper?

First line of your quote. I did say the A pad would move into the caliper not the rotor. You switched it on me.  Without the spring, the A pad will bang its way into the caliper from road irregularities. Believe me, people here have tried to run witout the spring and that's what happened. I ran one time with the spring way out of adjustment, and same result. Needed nearly 2 pulls on the lever to get the pads back where they should be.

With the spring AND the stop setting screw, the A pad retreats into the caliper but only as far as the stop screw wiill allow. 5-8 thou.

You're right, I meant to say caliper, not rotor. I guess I'll just have to accept the design and appreciate it for what it is.
[/quote]
Yeah, I call it a Garden Gate. It really was a revelation when I fully grasped how the whole brake works. Including how the square section ORing in the caliper  actually draws back the A pad when the lever is released. Like you I discovered later that other systems were more elegant, less moving parts. But, it really does work good when it's all right.