Diagnosing and Fixing a Seized Brake Caliper

When cars are running smoothly, everything is well. But from time to time they can throw up all sorts of problems leaving motorists stranded at the worst possible time. Would you know how to carry out a vehicle inspection in Perth if your car pulled to one side or you smelt burning? It could be that one or more of your brakes could be binding or seized. If the sheer thought of being left scratching your head with a broken car leaves you in a panic because Spot on Vehicle Inspections can help you diagnose and fix the problem with these expert tips for when carrying out either a pre-purchase car inspection or a used car inspection.

How to spot symptoms of a seized brake caliper

There can be any number of reasons why brakes drag or bind. It’s commonly because something in the system has become stuck. It could be that the piston sticks within the calliper or the brake pads may have skewed or seized. In other situations the slide pins seize on single-piston calipers. And if a vehicle has been left to sit in a damp environment for a long time, the pads can become stuck to the disc.

vehicle inspection checking brake disc and caliper in Perth

The symptoms are obvious to spot if a brake seizes when the vehicle is not in use. The brakes will feel like they are still on when you try to drive it. In some occasions it’s so bad, the car doesn’t move at all. But if it’s the caliper slide pins, which are the culprit, the car may appear to drive normally but the pads will only be pushed onto the disc from the piston side.  This results in reduced braking ability on one wheel while wearing the pad on the piston side quicker. In such circumstances, the vehicle may pull to the opposite side when hitting on the brakes. In other cases, if the pad is stuck, the car can feel low on power as if the parking brake is on. In this situation the car may also pull to the side when cruising despite not even applying the brake.

Other symptoms to look out for when carrying out your own used car inspection is when seized brakes get extremely hot. The smell of brakes overheating gives off a distinctive acrid smell and in some cases possible smoke. If this happens during either your pre-purchase car inspection or indeed used car inspection, stop. Driving with a badly binding brake can start a small fire. But even in the absence of a fire, discs can be severely damaged at the very least. Having said that, in many cases brakes binding on one wheel will happen gradually over time making it harder to notice especially when carrying out a pre-purchase inspection. The fault may not be diagnosed until the annual inspection when brakes are tested for proper function.


Why do brakes seize?

Put simply, inactivity alongside corrosion are the main reasons why brakes seize. It’s not uncommon for a car’s brakes to seize if it has been left sitting idle for months – especially if it is parked outside. Brake discs can rust resulting in pads to become stuck to them or a caliper piston. Slider pins can get stuck in the same way. Brakes are subject to easy corrosion because they are subjected to a huge range of temperatures, are constantly exposed to the elements and are hardly ever serviced or inspected between pad changes.

When checking the rear brakes during a used car inspection, the calliper or cylinder may not always be the cause. Sometimes the handbrake cable or mechanism can just pack up resulting in the brakes to remain on. To prevent this from happening, both should be regularly lubricated.  It is also a good idea to flush the fluid in your entire brake system every two years. Moisture from the water absorbed by the brake fluids can cause corrosion from within the caliper itself.

brake disc and caliper for pre purchase car inspection

How to unstick a seized brake calliper

The solution to your brake issue is straightforward if the cause is either the parking brake cable, a skewed pad or pads are stuck to the disc. When doing your own used car inspection, the problem can be fixed by lubricating the parking brake system. Removing the pads and rubbing some grease to the edge should fix skewed pads. Resurfacing the disc and replacing the pads should be done once stuck pads have been freed from a disc.

However, a special tool is needed to retract the pad when it comes to seized calliper pistons or slide pins. This tool is often a C-clamp. Seized caliper pistons can be removed with the hydraulic pressure off the brake system itself. After removing the caliper from the disc, pump the brake pedal to move the piston past the corroded section. You will then be able to disassemble and rebuild it.


Should you rebuild or replace a brake caliper?

When you free a stuck brake after carrying out a used car inspection, there is a chance of it seizing again if the caliper piston caused it or slide pins. The corrosion responsible for it to get stuck will still be there. Replacing the faulty caliper is an option but rebuilding can be a lot more cost effective. A competent person can rebuild it at home. The process involves disassembly and cleaning before replacing rubber parts and even the piston itself. A rebuild is worth considering when you discover during your used car inspection that the internal corrosion is not that bad. The only special tool you may need is a brake hone to clean the internal bore of the calliper.  But if your budget stretches, buying a brand new caliper is a good and easy option to go for which will save you all the hassle.

If you’re looking for a friendly thorough car-inspection in Perth, do not hesitate to contact Spot on Vehicle Inspections on 0407 193 506. Alternatively, you can fill out a form on their ‘Contact Page’ and one of the team members will be in touch.