How to Fix Sticky Brakes: Causes, Remedies and a Step-by-Step Diagnostic Guide
Brake calliper sticking isn’t that common, but it is important to have it diagnosed and fixed right away because it affects the safety of your vehicle. It is also widely referred to as a “seized calliper”
How to Diagnose Sticky Brakes
Do you find that your vehicle pulls more to one side when braking? Or perhaps the brakes don’t seem to release all the way after you let go of the pedal?
Here are some more steps to diagnose a seized calliper:
- Test drive the vehicle. A sticking or dragging caliper will not allow the brake pad to disengage from the surface of the brake rotor. Not only does this cause excessive premature brake pad and rotor wear, but the vehicle will be literally driving with the brakes slightly applied all the time. A telltale sign of a severely sticking caliper piston is the vehicle pulling to one side when driving. If you constantly have to hold the steering wheel in place, it may not have anything to do with steering or wheel alignment. This can also stress the transmission of the vehicle.
- Test the heat coming off the wheels after the test drive by placing your hand near the wheel without touching it. Sticking calipers will cause brake pads to constantly drag on the rotors of the braking system and this will create a tremendous amount of heat. The heat will then transfer to the wheel/rim of the tire. Be careful not to directly touch the tire rim as the heat can cause severe burns.
- Lift the vehicle with a floor jack and secure it on jack stands to visually inspect the difference in brake pad wear from one side to the other. While pads wearing more on one side may simply mean that pads are improperly lubricated and stuck in the bridge of a caliper, it could also indicate the onset of a sticking caliper piston.
- Remove the lug nuts with the lug wrench and remove the wheels.
- Place the top of a large C-clamp over the inboard caliper housing and the bottom of the clamp onto the outboard pad and tighten the clamp to ascertain if the caliper piston is sticking or stuck. A properly functioning caliper will allow you to tighten the C-clamp and compress the caliper piston. A sticking caliper is going to be very difficult, if not impossible, to compress. Compare one caliper on the same axle to the other. Be careful when applying this procedure to rear calipers on certain vehicles as some caliper pistons (on some imports) require a screw-in caliper piston and will not compress by squeezing with a C-clamp.
- Remove the caliper mounting bolts and attach the caliper to the chassis of the vehicle with mechanics wire. Do not allow the caliper to dangle precariously from the rubber brake hose.
- Remove the pads from the bridge of the caliper, but mark them or position them after removal in order to remember how to replace them in their exact, original position. If the pads are stuck in the bridge and need to be forced or pried out with a screwdriver, this may be the root of the problem and not the caliper piston sticking. Clean the caliper bridge surface using a wire brush or an angled die grinder and a reconditioning disk. Remove and clean the metal hardware and then replace it. Apply a liberal coat of brake lubricant to the pad contact points of the hardware and the bridge. This could revive the braking system if the problem has not done too much damage to the brake pads already.
- Take an overall measurement of each brake pad’s thickness using a tire tread depth gauge or a micrometer. Take several measurements of each pad in different locations and compare the measurements to the other pads. While there will be some variance in wear, perhaps even on the same pad, an obvious visual variance in pad thickness may be an indication of a sticking caliper. A front brake pad wearing down below 4/32 of an inch is getting close to needing replacement. A rear brake pad wearing down below 3/32 is getting close to needing replacement. Rear disc brakes do not work as hard as the front pair, so less friction material on the pad is more acceptab
If you experience any of this, then you may indeed have a stuck brake calliper. Before you take your vehicle down to a repair shop, learn what causes brake callipers to stick and how you can fix them.
What Causes A Seized Calliper?
The main cause of brakes seizing is inactivity, coupled with corrosion. If a vehicle is left sitting for months it’s not uncommon for the brakes to seize, especially if it is parked outside. Brake discs can rust causing the pads to become stuck to them, or a caliper piston, or slider pin can get stuck for similar reasons. Brakes are subjected to a huge range of temperatures, are permanently exposed to the elements, and are rarely serviced or inspected between pad changes. As a result, corrosion can build up in key areas and cause failure.
In the case of the rear brakes binding, it may not be the caliper/cylinder. Sometimes the handbrake cable or mechanism can just hang up, causing the brakes to remain on. To prevent a seized handbrake cable or mechanism, both should be lubricated periodically.
Also, remember to flush the fluid in your entire brake system every other year. Most brake fluids absorb water over time, and moisture can cause corrosion from within the calliper itself.
How to Fix a Sticky Brake
Even if you free a stuck brake, there is a high likelihood of it seizing again if it was caused by the calliper piston, or slide pins. The corrosion that caused the unit to get stuck is still there, and it is only a matter of time before it sticks again. Replacing the bad calliper is always an option, but often it can be rebuilt for less money.
A rebuild is something a competent DIYer can do at home, and involves disassembly and cleaning, then replacing rubber parts and sometimes the piston itself. As long as the internal corrosion isn’t too bad, a rebuild is worth considering. A brake hone to clean the internal bore of the caliper is the only special tool you may need.
You may want to buy a good used caliper and rebuild it with new seals instead, if yours is badly corroded. But remember, a junkyard caliper could even be worse than the one you’re replacing!
If your wallet allows, the simplest, and wisest option is always a brand new caliper! Ultimately it comes down to budget.
Why not get a competitive quote from us at Astro Brake? Click here to get in touch with us today!
Credit to sources: