Caliper brake lubrication

Question

Good day all, I have a question about caliper brake maintenance. Occasionally, my caliper brakes remain a little "stuck" closed, in that I have to manually open them/spread them back out in order to drive away the brake pads from the braking track.

I have temporarily remedied this condition just by pouring some water on the calipers (at the location the blue arrow is pointing to):

the brakes' correct functionality is restored for a while when I add the water there. This makes me think that they just need to be lubricated to make the "fix" longer lasting/permanent.

So, my question is: is lubrication allowed (and advised) in correspondence of the blue arrow? Are there some specific products? Some people told me to avoid WD-40, firstly because it's too volatile, and then because it's highly aggressive towards plastic parts. So, I wish to know what products I have to search, and if it's a common maintenance to do.

Answer 1

As you surmised already, you are suffering from a sticky caliper, and have diagnosed the solution, that is, a little lubrication.

I think most any lubricant would do, but some suggestions would be:

• Silicone-based - usually this comes in a spray can, so you would need to protect the braking surfaces (pads, rims) in the general area to avoid any overspray from getting on these friction surfaces. The spray product should have a small tube for use in directing the silicone lubricant into the location you need even better. Silicone-based lubricants tend to not attract dust/dirt so they are pretty ideal for this location.

• Teflon-based - Teflon is pretty slick too, similar to silicone. Many chain lubricants have this carried in the liquid. Just a single drop (or two) might be all you need. Just apply it sparingly and allow gravity to draw the drop of lubricant to flow to the pivot point that is sticking.

Tips:

• for spray lubricants, do a test spray away from the location first to judge the amount of lubricant that will be administered, and to get a little feel for how to deliver a small, directed shot of lubricant. Think of it as practice. You only want to get lubricant at the pivot point, not everywhere else.

• Protect and cover the rims and brake pads from getting lubricant on them while applying lubricant - ESPECIALLY with sprays. Lubricant on the friction surfaces (pads, rims) is a safety concern. So do not rush the job, especially if you are unfamiliar with the process.

• After care: once you have applied lubricant to the pivot, make sure you watch out for the lubricant travelling past the pivot, down the arms and towards the pads. It would be good to wipe the area below the pivot down with a clean, dry rag or paper towel soon after applying lubrication, and for a few days after, just to be sure.

You mentioned WD-40 in your question. WD stands for "water displacement" and the 40 represents the 40th formulation they tried during formulation while the product was being developed. It is not considered a lubricant as much as it is a water displacement product. But many have used it as a light lubricant, although its lubricant properties are not long lasting.

Answer 2

How confident are you with hand tools?

I've had several sticky rim calipers, and one longer-lived solution is to disassemble and clean the insides of the pivot.

Downside, there's a lot of parts and you don't want to loose any of them. Dual pivot as pictured are more complex than single pivot, but tend to reassemble easier because of the multiple springs. A single pivot caliper also has to have the right torque levels applied to even-out the spring tension on both sides.

You might get some improvement dunking the assembled caliper in an ultrasonic cleaner, but disassembly is the way to go. You can also identify any burrs and stone/sand/file them. Every small improvement adds up.

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Another possibility is that your cables have a small amount of sticktion from rust, or a lay of wire is broken and digging in somewhere, adding just a little resistance but enough to overcome the spring in the brake caliper.

It may require a new inner/outer cable fitted, which is a wear item. You can test this by releasing the wire from the pinch bolt on the caliper, and test individually.