“Caliper pin stuck” isn’t a phrase that rolls off the tongue, but thanks to Google it’s probably why you’re reading this. People googled that phrase and similar ones, like “stuck brake caliper pin,” over 30,000 times last year. So a stuck caliper pin and its nasty sibling, a seized caliper pin, are things lots of people deal with. They’re problems that can come from reusing old parts during brake jobs, or using the wrong brake grease. Here’s a link to the Carlson sales support page, if you need to order new caliper pins and dust boots.  — Motor City Mitch

THE SIGN

Years ago, I was driving north on Highway 101 in California, half-listening to Dr. Dean Edell on the radio, when I fell asleep. I woke up going full-speed on the gravel shoulder and panicked. I jerked the steering wheel left. My car popped onto the highway, crossed both lanes and went into the median. Then I over-corrected, veering back across the highway and into a grass field, heading straight towards a large highway sign reading: VANDENBERG AFB NEXT RIGHT. I slammed my brakes and my Toyota began bouncing, like a stone skipping across a pond. As it came to a stop, it slowly rolled over and leaned upside down against the sign. It was almost elegant. Later, the only evidence of the accident (other than my buckled car roof) was a bit of paint on one of the sign’s wooden posts.

That experience left me with admiration and gratitude for the disc brake system.

Thank you, brakes.

THE GENIUS OF DISC BRAKES

My old Toyota had “floating caliper” disc brakes. They’re commonplace these days, having replaced drum brakes during the 1970s and 1980s as the go-to way of stopping a car. In my view they won for the right reason: simple, ingenious design. You press a pedal and friction pads squeeze spinning discs attached to your wheels. Simple.

The genius is the design of a disc brake caliper, a crescent-shaped assembly of parts next to your wheel. When you brake, you push fluid into into the caliper, forcing a piston into a brake pad, and the pad into the spinning disc, known as a rotor. That’s when the magic happens. As the rotor blocks the piston’s movement, the caliper itself slides back towards the car along two little rails called guide pins. That sliding pulls a second brake pad against the outside of the rotor. The upshot? You’re squeezing the rotor from two sides equally. It’s a great way to stop a car.

I found this animation in a YouTube video that does a nice job showing how the caliper slides…

A STUCK BRAKE CALIPER

A stuck brake caliper means the caliper isn’t sliding right. Or it’s not sliding at all. And as you drive, you may hear squeaking when you brake, or just feel like something isn’t right.

There are several possible causes. Something could be wrong with the brake line or piston. But often the problem is a stuck caliper pin. One or both of the little rails the caliper slides along — the caliper guide pins — get sluggish or seized. And that means your caliper won’t slide, and the outside brake pad won’t fully squeeze your rotor.

That’s “caliper pin stuck.”

A STUCK CALIPER & UNEVEN BRAKE PAD WEAR

One sign that you’ve got a stuck or seized caliper is that your brake pads aren’t wearing evenly. The outer pad isn’t squeezing hard against the rotor, so it’s not wearing out as fast as the inside pad.

In the video below, ChrisFix, a hugely popular mechanic on YouTube, shows the uneven wear on pads he took from a 2008 Honda Accord. He explains how the unevenness could, in theory, be caused by a crooked piston. But as he shows, the problem isn’t a piston, but a stuck brake caliper pin.

REPLACING A STUCK BRAKE CALIPER

Before we dive into the nitty gritty of dealing with “caliper pin stuck,” there’s an option worth mentioning up-front: Replace the whole caliper.

In the next video, Brian of South Main Auto — another popular YouTube mechanic — deals with some nasty-looking brakes on a Prius. Rather than repairing the calipers, he just replaces them, along with the rotors and pads. In other words, a complete brake job. By doing that, he makes everything new, from seals to pre-lubricated guide pins. The cost? On RockAuto, a new caliper for a 2015 Prius, including the bracket with new pre-lubricated caliper pins starts at 53 bucks.

HAMMERING OFF A SEIZED CALIPER

To deal with a stuck or seized caliper pin, the first thing is to get access to it. There are various ways of doing that. Perhaps the simplest is to take a sledge hammer and knock the caliper off the caliper bracket — the bottom part of the caliper that’s bolted to the car.

In the video below, Scott Kilmer, another popular mechanic on YouTube, uses a 3-pound Estwing hammer to do just that. He’s working on the rear brake of a Toyota. Note that he first removes a bolt behind the caliper to get the brake hose out of the way.

PULLING OUT A STUCK CALIPER PIN

Another way to get access to a “caliper pin stuck” is to pull it out although this probably won’t work on a frozen or seized caliper pin.

In 2013, the YouTube mechanic Fixbook posted a “how to” video that has close to half a million views. In it, he uses a socket wrench to twist the end of the stuck caliper pin back and forth. Then he does the same with vise-grips, intermittently using a hammer and screwdriver. Although he eventually resorts to a propane torch (something we’ll cover in a moment), his video shows the pulling technique in action.

REMOVING A SEIZED CALIPER PIN WITH ITS OWN BOLT

The next idea is both clever and simple. It uses the bolt that goes into the end of the caliper pin as a lever to simply force it out.

A YouTube mechanic going by the name Alpha G Male has a video in which he puts washers and a coupling over the end of a stuck caliper pin on a Nissan Altima. Then he tightens the slide pin’s bolt, screwing it into the pin. The washers and coupling create a lever — and he just cranks the stuck caliper pin out. Simple and effective.

TORCHING A STUCK BRAKE CALIPER PIN

“Heat is the way to get these out,” says Brian of BriansMobile1, referring to a seized caliper pin in a YouTube video with over 200,000 views.

In the video, he deals with a stuck brake caliper pin from a GMC Sonoma. He clamps the caliper bracket into a vise and heats it up the area surrounding the pin with a Bernzomatic propane torch. After about five minutes, he’s loosened the pin enough to pull it out with vise-grips.

REPLACING A STUCK BRAKE CALIPER BRACKET

The YouTube auto repair channel CarsNToys shows another way to go: replace the bracket (which contains new pins).

“After 20 minutes of having zero success,” the mechanic says, “I decided to purchase a new caliper mounting bracket, caliper pins, and the pin boots for $30.”

In the video, he tries to knock out a seized caliper pin with a flat-head screwdriver and a sledge hammer. He pounds, and the pin bends but won’t budge. Next he shows the new bracket he bought from AutoZone. The new bracket contains new slide pins and rubber seals.

If you’re interested in getting new slide pins and boots yourself (more on boots in a moment), here’s a link to the Carlson sales support page.

CLEANING OR REPLACING SEIZED CALIPER PINS

Every mechanic in this story who cleans a caliper pin does so using either a wire brush or a wire wheel, basically buffing off any rust or gunk they see. Some of them also clean the inside of the bores that hold the pins.

As an alternative, a YouTube mechanic that goes by the moniker innocuous_name has a video with over 100,000 views on “How to Remove a Frozen Caliper Pin in Less Than 5 Minutes.” He removes the pin using a torch. But he has no intention of cleaning it.

“I’m assuming I’m going to ruin this pin,” he says. “I’m going to replace it. Replacing the pair is only going to be five and half bucks.”

“It’s going to be a lot of trouble to get it buffed out. It’s not worth your time or risking your safety.”

LUBRICATE SLIDE PINS WITH SILICONE

To lubricate slide pins, two types of brake grease are proven to work — silicone and PAG (Polyalkylene Glycol). That’s according to Gary Weber of Dow Corning. (For details, check out his presentation Smart NVH Solutions for Next Generation Brake Design and look at the 11th slide.)

Silicone and PAG are synthetic greases — two of the six types of synthetic grease. What Weber is saying, and a number of mechanics agree, is that some brake greases don’t work well on pins. That includes petroleum-based greases and several types of synthetic grease.

One issue is how grease impacts rubber seals. A caliper slide pin has a rubber boot that seals out dirt, and often has a rubber bushing for movement and support. If you’re not using silicone or PAG, these rubber parts can swell.

[For more, check out Larry Carley’s article on Brake & Front End). To see an example of swelled slide pin boots and bushings because of using the wrong grease, check out this YouTube video by dialtofast.]

A second issue is spelled out nicely by a hugely popular YouTube mechanic, Eric the Car Guy: “If you use regular grease, it will dry out and cause the pins to seize.”

Here’s an excerpt from his video, where he lubricates his guide pins with 3M Silicone Paste…

INSTALLING CALIPER PIN BOOTS

As mentioned above, caliper pins have rubber boots that protect them and keep them clean. And often they have rubber bushings to help with movement and support. The cost to replace the rubber parts during a brake job? For all the brakes on a 2015 Toyota RAV4, the cost at RockAuto is less than $6.

So how do you put a caliper pin boot onto a pin? The YouTube mechanic Kowyn has a video that shows how. Because he’s filming and doing the work one-handed, he struggles a bit, and that ironically makes his explanation more effective…

CONCLUSION

I hope that you found what you were looking for on this page. What a “caliper pin stuck” is and how to deal with it. How to remove it. How to clean or replace it. And what kind of grease to use on it.

According to YourMechanic, brake pads last between 25,000 and 70,000 miles, depending where you live and how you drive. In other words, when you get your next brake job, the distance you’ll have driven since your last one will be, on average, equivalent to 18 trips from New York to LA. That’s two trips around the earth. By that time, your brake pads are shot and other parts of your brake system are worn too, so replace the hardware on your next brake job.

On that California day years ago, I had to climb straight up and out the passenger door of my Toyota to get out. By the time my feet hit the ground, a fire truck had arrived. A fireman looked me up and down and saw I was fine. Then he helped me push my car off the Vandenberg AFB sign, which was as easy as shoving a refrigerator a few feet across a kitchen floor. He paused before leaving, looked at me and said, “It’s your lucky day.”

I’ll say it again: Thank you, brakes.