Checking brake pads is one of the most important and luckily easiest maintenance chores. Pads are not something you want to run out of and so keeping tabs on how worn they are is critical for brake performance and for preventing brake component damage.
I’m a mechanic for over two decades and in this post, I’ll show how to nail measuring your pads the easy way.
To check brake pad wear use a brake pad inspection tool to estimate brake pad lining wear.
In this post you’ll learn how to inspect your brake pad wear the easy way, I’ll also share top mechanics tips for fitting pads.
Brake systems are designed to give you the heads up on brake pad wear, some brake pads have a built-in metal tang that’s positioned at the min pad material (2-3mm). When the tang makes contact with the rotor, it’s like nails on a blackboard, effective but irritating.
More sophisticated makes use of a brake pad mounted sensor and a more subtle warning light on the dashboard.
Tools to Check Brake Pads
To check brake pad wear like a pro you’ll require a tool known as a brake pad inspection tool.
A small LED light would be great too or your smartphone will do the job.
A brake pad inspection tool is as cheap as chips and a real-time saver, you can check out the type I use here on the brake tool page.
Pad Checking Process
Modern cars have us mechanics spoiled, or at least when it comes to brake inspection. Older cars required jacking up and wheel removal to inspect the pad lining, not so with most modern cars. Generally, the latest model vehicles won’t require that much work thanks to the modern open-spoked wheel design.
The inspection process is as follows:
- Park the vehicle on a level surface
- Use the inspection light to light the outer brake pad lining (or use a phone light)
- Estimate the correct tool blade size by eye and offer it up to the brake pad
- Now select the blade size closest to the pad lining – that’s your pad wear, easy right?
Measure the lining material, but don’t include the backing plate.
The pad inspection tool employs measuring blades which are conveniently color coded using the traffic light system:
- Red – replace imminently 3mm or less
- Orange (yellow) – advise replacing soon between 4 and 6mm
- Green – all good between 8 and 12mm
Now this way of checking the pads isn’t foolproof, as you may have noticed, the tool can only access the outer brake pad. The inner pad is canceled by the rotor.
The trouble is, floating calipers by their nature tend to wear the outer less than the inner pad. The difference shouldn’t be huge if it is you have a caliper or slide pin issue.
Anyhow, the point is if the outer pad measures orange verging on red, you can bet the inner pad is in the red and so pads are required, like right now.
The other shortcoming of this inspection tool is it results in fewer wheel-off full brake inspections and that presents issues like wheel-to-hub corrosion which often causes a wheel to stick to the hub……a right royal pain in the hiney when you’re changing a flat.
The fix is a little brute force in the right spot and some copper paste, I’ve covered the complete fix here in this post “Wheel won’t come off.”
Mechanics Brake Pad Tips
- Buy the best quality brake pads the budget allows
- Use anti-squeal on pads and caliper rail
- Clean and lube (synthetic grease) caliper slide pins
- Copper grease hub to wheel hub interface
- Before commencing rear pad replacement, check if you require a scan tool and a wind back tool
- Use a torque wrench to tighten road wheels in a star sequence
You may find the following posts helpful:
- Brake system resources page
- Brake pad replacement stepped guide
- About the Author
- Latest Posts
John Cunningham is an Automotive Technician and writer on Rustyautos.com. He’s been a mechanic for over twenty-five years and has worked for GM, Volvo, Volkswagen, Land Rover, and Jaguar dealerships.
John uses his know-how and experience to write fluff-free articles that help fellow gearheads with all aspects of vehicle ownership, including maintenance, repair, and troubleshooting.