Vintage sidepull caliper brakes misaligned
 

I got a used pair of Shimano 105 BR-1050 sidepull caliper brakes to try out. I have the matching brake levers too.

They work great, but I noticed that the front brake shoes are pretty dramatically offset from each other when viewed from the top.

I don't see any issue with the braking power. The rear brakes don't have this issue (the 2 brake shoes line up when viewed overhead).

What might cause this? One of the arms is slightly bent perhaps? Is it an issue that should be addressed? Or a common issue that can be lived with?

https://cimg2.ibsrv.net/gimg/bikefor...f33a8a9272.jpg
https://cimg3.ibsrv.net/gimg/bikefor...a221aba95e.jpg

Front brakes can be bent if the fork swings around and the brake hits the frame. Could be the arm, could be the pivot bolt. At first glance I'd say the bolt is bent slightly to the left, but you'd really need to pull it apart to be sure. Yours doesn't look bad enough to worry about.

That one pad is slightly "ahead" of the other is not in its self a problem. Lots of calipers have this whether intended or from some insult the caliper saw (like in the front when the fork/bars swing around so far and forcibly that the caliper's cable casing stop/adjuster arm hits the down tube and gets bent. This bending can bring the other branch of that arm, the pad holding portion, along with it. Not common with nice short reach calipers but can happen. Sometimes I can point out the paint damage on the down tube to the customer as proof of my theory.

Sometimes this pad arrangement can be from the central pivot being so loose/sloppy that the arms flop about. But this usually is easy to see and feel for.

How do the rear pads align WRT each other?

It's hard to tell completely but is the front wheel centered in the fork? Andy.

Yep, the front wheel is centered in the fork. I had a Campagnolo caliper on here prior and the pads were aligned, so I don't think it's anything with the bike itself.
Here's a pic of the rear. The pads look fine there.
https://cimg3.ibsrv.net/gimg/bikefor...51416cda24.jpg

Ahh, that's a good point about the bolt being bent. I hadn't considered that. Next time I disassemble it to clean it, I can check. Maybe hold it against a right-angle speed square? If it is bent, is it even worth trying to straighten, or just try to find a replacement bolt? Or like you said, just leave it be.

Just roll it on a flat surface, a slight wiggle should be fairly obvious. Depending on where the bend is, it might be as simple as clamping it in soft jaws and tapping with a soft-face hammer. But it's really not enough to worry about.

I AM rubber, you are (tubular) glue!...

the Wheels are not centered in the frame or fork correctly.
the slight misalignment of the pads (front to rear) you see is not an issue on the rear brake, but is an issue on that front brake/fork.
check to verify one of the pads is not upside down... and yes, brake caliper arms do get bent sometimes... the alignment of the vertical pad adjust slots can be eyeballed to find a bent arm... wheel out, possibly remove the pads, and compare the slots.
Front calipers are the most susceptible to getting bent... from impacts or storage mistakes.

the wheels not being centered is an issue to be concerned about.
did you install the front wheel with the bike upright? if so, the axle is not fully seated in the dropouts.
the rear wheel is only slightly out of align... a slightly smaller axle diameter can cause that much of a misalignment, or an incorrectly centered hub/rim, or poorly done "truing" job can do that.

You have play in the caliper?

I've owned these calipers, along with the Shimano 600 versions. I suspect the main pivot bolt is bent. I'm not a fan of bending or straightening threaded bolts or rods, due to the risk of cracking and failure, at perhaps the most critical part of the bike. If the threaded bolt fails here, the front brake comes shooting off of the front of the bike, dangling around on the end of the brake housing, until it gets caught up in the wheel, and then things get fun.

Second issue, having owned these brakes, I can testify that even with great pads and perfect setup, they were among the most underwhelming calipers I've every used. Flexy arms and low mechanical advantage due to the short arms. I don't know what Shimano was thinking with these. Any dual-pivot caliper on the front will be an improvement, such as the next generation Shimano 105, RX100 or RSX or whatever.

I suggest you proceed directly past any fixes or further diagnosis on this, and get yourself a better caliper.

I don't understand the assessment? The overhead misalignment is still visible when I take the caliper off the bike, as shown here:
https://cimg2.ibsrv.net/gimg/bikefor...568e574e8e.jpg

Yeah these probably won't be on there for long. I just wanted to try the 1050 levers and calipers together to see what the "Shimano Linear Response" felt like and why Sheldon Brown was so keen on it.
I have a pair of Shimano BR-7800 dual pivots waiting in the wings to be installed in a couple of weeks.

Definitely no play. The back and front feel the same.

It doesn't look "as bad" though.

You might want to disassemble the brake to check the arm alignment. If I remember the 1050 caliper correctly, there are two outside nuts to adjust the arm play. And a ring of tiny bearings lies between them.

https://cimg2.ibsrv.net/gimg/bikefor...c2c4fa49a9.jpg

When I look at other pics of 1050 calipers on the web, they don't all use two nuts, which is always so confusing for me to adjust (like my Modolo calipers).

You could toe in that right arm a little and left arm out. The pads should adjust enough to bring them inline. That right pad does look worn more towards the back.

Another thought based on this photo ...

https://cimg3.ibsrv.net/gimg/bikefor...8cb026ffbd.jpg


The pads are the same, but maybe the holders are different versions? :foo: Is that possible? You can sorta tell at the end of the holder (in yellow) that it looks like a different design. At least switch the two pads between the arms to see what effect that has. Check the rear brake to see if those holders also are slightly different. Obviously, the Dura pad itself didn't change in overall length, but maybe this particular KS holder did change. This could just be partly the issue and not the complete answer. The earlier pics weren't very clear about a perfectly centered wheel.

As far as I know, all of these Dura holders are specifically L or R, not both.

It does seem like it should have a 2nd nut on the front, right? Like how Campagnolo brakes do.
But on the Shimano exploded diagram, I don't see one, so maybe this is the way it's supposed to be.
You're right about the ball bearings. I took it apart and held the arms together. I'm pretty sure one of them is bent, though the odd thing is I don't see any wrinkle marks or anything where the metal got bent. Is it possible it was just defective?
I know this is more trouble than it's worth at this point, but I'm getting obsessed in a detective way.
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https://cimg2.ibsrv.net/gimg/bikefor...30819ac093.jpg
https://cimg3.ibsrv.net/gimg/bikefor...245215f15a.jpg
https://cimg4.ibsrv.net/gimg/bikefor...104bff91f5.jpg
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"You couldn't stop a three-year-old's tricycle!

"Your mother was stamped steel!"

"Short reach? How about NO reach!"

:)

(honestly, I'm surprised my own brakes haven't decided to just up and quit on me. Perhaps they're plotting something...

That was an interesting thought on the holders. I took the pads out and held them against each other. They're definitely a match.
I think the arms are both bent in the same direction. I held it up against a switch to use as a straightedge, and drew the red box, and you can see how both arms seem to angle to the left.

https://cimg6.ibsrv.net/gimg/bikefor...d212d41d88.jpg
https://cimg4.ibsrv.net/gimg/bikefor...b1847016e2.jpg
https://cimg4.ibsrv.net/gimg/bikefor...6f43d7c3a4.jpg

They do look the same. But are they possibly a match in a bad way? Meaning they're both the same side? Not L/R, but R/R or L/L? The guides under the holder may tell you or they may not. Does it read L or R inside the holder where the pad fits? It might say forward left or forward right.

These don't have any indicator inside (1st pic), but I know what you're talking about, because I have an older KoolStop holder on another bike and those do have side indicators (2nd/3rd pics).
https://cimg6.ibsrv.net/gimg/bikefor...9c3d898698.jpg
https://cimg7.ibsrv.net/gimg/bikefor...c6c0c42972.jpg
https://cimg8.ibsrv.net/gimg/bikefor...843b160198.jpg

Yeah, it sounds like the holder is not the issue. Switch the calipers between front and rear to see if there's any difference there. And that pretty much exhausts my knowledge. I don't know much about actually bending arms, outside the little I've done towing-in brake pads. Good luck!

Thank you! I appreciate you taking the time to examine it. That's a good idea about reversing the front and back. I think I'll disassemble the back one and compare the arms. It's interesting you mention towing-in brake pads....I wonder if that's how this happened? Maybe the person was trying to bend the arms to create slight toe-in and got overzealous?

You can bend those a little. Probably bent trying to install inflated tires with the quick release closed.

That is probably the most likely cause as it was standard practice years ago to twist the arms for toe-in and some ham-fisted folks would get carried away but it really doesn't matter at this point as it just needs bending back. You just need to determine which arm is the bent one.