How to Test Brake Caliper Guide Pins

Image Gallery: Brakes It's important to keep all parts of your brakes in proper working order. See more pictures of brakes.
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There are some car problems you simply shouldn't ignore. Brake problems are perhaps chief among them. A car that can't stop, or has trouble stopping, is dangerous for the driver and everyone else on the road. That's why it's important to keep all parts of your brakes in proper working order.

First, let's talk about brake calipers and what they do. On a disc-brake-equipped car, the caliper sits over the brake rotor (the circular metal disk inside your wheel) like a clamp. Inside the caliper is a brake pad, a small block of friction material backed with a metal plate. When you step on your brake pedal, pistons inside the caliper cause it to apply pressure to the brake pad which squeezes the rotor, causing the car to slow or stop.

That's the idea, anyway. But if one or more parts of your brake calipers aren't working correctly or if they're installed improperly, you could experience trouble with stopping. When you're performing work on your brakes, you have to ensure there aren't any problems with your caliper guide pins.

The caliper guide pins are two round metal pins on each brake caliper where the brake piston assembly sits. They're called guide pins because they're responsible for guiding the proper angle for how the brake pad meets the rotor.

On the next page, we'll explore how to determine whether or not your brake caliper guide pins are causing problems, and explain how to fix them if they are.

Diagnosing Brake Caliper Guide Pin Problems

It's a good idea to check the pins whenever you're changing the pads yourself.
It's a good idea to check the pins whenever you're changing the pads yourself.
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If you're having issues with your brakes, the culprit could be the guide pins, but a careful inspection is the only way to know for sure.

When you're changing your brake pads yourself, part of the job will be removing the guide pins. But what happens if you put the pins back improperly? Then you could experience noises or problems stopping. The brakes could stick or grab when you're driving, or you could hear a grinding noise if the calipers aren't meeting the rotor at the proper angle.

So how do you know if the guide pins are at fault? You'll need to inspect the brakes like you're about to change the pads. In fact, it's a good idea to check the pins whenever you're changing the pads yourself. Lift the car, remove the tires, take the caliper off and look at the caliper housing. See those pins at the top of the housing? Those are the guide pins. Most cars have two guide pins with a rubber housing surrounding each [source: Dan's Garage].

Problems to look for include caliper pins that are corroded, or ones that aren't properly lubricated. Also, the pins could be stuck in the rotor or they won't go in all the way after the pads have been replaced.

The pins should be easy to take out with a screwdriver and a few light taps from a hammer. Caliper pin removal tools are also available at auto parts stores. If the guide pins are really stuck in there, or if they're rusted in place, you may have a problem on your hands. In that case, you'll need to find an experienced mechanic to discuss your options.

Next, let's discuss the proper way to re-insert the guide pins.

Greasing Brake Caliper Guide Pins

Brakes generate a tremendous amount of heat because they're essentially a piece of metal used to slow down another piece of metal moving at highway speeds.
Brakes generate a tremendous amount of heat because they're essentially a piece of metal used to slow down another piece of metal moving at highway speeds.
iStockphoto/Thinkstock

Before we re-insert the caliper guide pins into the caliper housing, they need to be properly lubricated. But remember, it's always best to check your vehicle's service manual before doing this kind of work.

You're going to need some high-temperature grease. This is a synthetic lubricant designed for machinery that can withstand temperatures of several hundreds of degrees Fahrenheit. Brakes generate a tremendous amount of heat because they're essentially a piece of metal used to slow down another piece of metal moving at highway speeds. The last thing you'll want is for the lubrication on your brake caliper pins to be unable to take the heat.

First, thoroughly clean the brake caliper guide pins, removing any excess grease or dirt leftover from when they were inside the caliper. Coat them in a layer of the high temperature grease. From there, you can re-insert the pins back into the caliper housing. They should slide right in if you used enough grease. Once those are back in place, you can complete the rest of your brake work -- like replacing the pads and reinstalling the caliper.

Some auto repair shops will skip the step of lubricating the guide pins. But while some say it's not essential, it's a good step in keeping your brakes operational and making sure they can stand up to the wear and tear they'll face on the road.

For more information about brakes and other related topics, follow the links on the next page.

Related Articles

Sources

  • AutoZone.com. "Repair Guide - Front Caliper." (Dec. 2, 2010) http://www.autozone.com/autozone/repairinfo/repairguide/repairGuideContent.jsp ?chapterTitle=Front+Disc+Brakes&partName=Brakes &pageId=0900c1528006e0c0&subChapterTitle=Front+Caliper&partId=0900c1528006e0b0
  • Danoland.com. "Changing Front Brake Pads." (Dec. 2, 2010) http://www.danoland.com/nsxgarage/brakes/frontpads/frontpads.html
  • McGovern's Auto Repair. "Brake Inspections." (Dec. 2, 2010) http://www.mcgovernsauto.com/auto_tips_brake_inspection.html
  • RepairPal.com. "Auto Repair Encyclopedia: Brake Caliper Pins." (Dec. 2, 2010) http://repairpal.com/brake-caliper-pins