The hydraulic part of a drum brake system is the wheel cylinder which receives brake fluid under pressure from the master cylinder when the brake is applied. It has two cups inside that seal and hold pressure and two pistons that move out under that pressure; pushing the rear brake shoes against the drum.
Drum brakes were very common on older vehicles and are becoming less common as ABS has become almost universal (it was required in the EU as of 2004 and in the US as of 2013). While disk brakes apply and released very quickly, drum brakes act more slowly and with less precise control of stopping power, so they are less suitable for use in an ABS system.
Cost of Wheel Cylinder Replacement
For some estimates on wheel cylinder replacement cost on some common vehicles, using $100 an hour as a labor rate:
- For a 1999 Chevrolet Tahoe, the labor time for wheel cylinder replacement is approximately 1.4 hours. A factory wheel cylinder costs around $80 on average (there are four different brake options for this vehicle) and a Raybestos replacement part costs around $8. The total job cost would be about $220 using OE parts and about $148 using aftermarket parts.
- For a 2008 Toyota Corolla, the estimated labor time for wheel cylinder replacement is around 1.4 hours. A factory wheel cylinder costs about $60 and a Beck/Arnley replacement part costs around $10. The total job cost would be around $200 with OE parts and about $150 with aftermarket parts.
- For a 2004 Dodge Neon, the wheel cylinder replacement will take about 1.5 hours. A factory wheel cylinder costs approximately $64 and a Centric replacement part costs about $8. The total job costs around $214 using OE parts and around $158 using aftermarket parts.
- For a 2008 Suzuki Grand Vitara, the labor time for this vehicle is around 1.6 hours. A factory wheel cylinder costs around $119 and a Wagner replacement part costs around $15. The total job costs around $279 using factory parts and around $175 using aftermarket parts.
It is worth adding that wheel cylinders can often be rebuilt, though the cost in parts and labor is usually about the same as replacement. Whether to rebuild or replace can depend more on convenience, what parts are available, than on the cost of either choice.
Saving costs on a wheel cylinder replacement often comes down to what else is wrong with the vehicle. Usually the work is done in conjunction with other brake work, and sometimes a wheel cylinder will be treated as a small add-on parts cost to a package brake job. This is more common at shops that specialize in brake work. Given the relative rarity of drum brake systems on modern cars, it isn’t always a safe assumption that a general mechanic will have expertise in drum brakes these days; it’s not a bad idea to inquire beforehand.
Wheel Cylinder Replacement
Some economy vehicles still use drum brakes on the rear and many light trucks still use them the same way.
Replacing a wheel cylinder is usually a simple matter. The wheel and brake drum are removed, the brake line is detached, and the wheel cylinder pistons are retracted from the shoes.
Then, the bolts holding the wheel cylinder to the backing plate are removed; allowing the wheel cylinder to be removed. Installation is the reverse and then, the new cylinder is bled.
Other Things to Consider
Once in a blue moon, a wheel cylinder will fail due to the piston seizing in the cylinder bore. However, the great majority of the time, they are replaced either because they are leaking or as a matter of maintenance during a normal brake job.
If the wheel cylinder is replaced during a brake job, usually, the wheel cylinder and labor will be included in a package price. If it’s added on to the job, the majority of the labor times above include removing brake shoes which makes most of the time over-lapping. A wheel cylinder replacement, then, would be a small additional labor charge to a brake job price rather than the 1.5 hours or so if replaced by itself.
If a wheel cylinder leaks badly, there is a good chance that the brake shoes wind up soaked with brake fluid. Sometimes if it’s minor, it is possible to clean brake shoes up and reuse them as brake fluid itself isn’t corrosive or generally harmful to friction material.
But if the shoes are fully saturated, it may not be possible to effectively clean them. As with most things on a safety-related repair, if there is doubt about the brake shoes being reliable, they will probably be recommended to be replaced.
As mentioned, the wheel cylinder labor includes removing the brake shoes, so it would normally be done as an additional parts charge with no labor added.
Sometimes a wheel cylinder seal will fail and leak simply due to age. The seals are rubber which hardens up and loses flexibility over time.
The other thing that causes them to leak is wear from accumulated debris in the system. The wheel cylinder sits at a low point so that’s where it tends to go. Flushing the brake system to ensure clean good fluid is a common recommendation at the time of wheel cylinder replacement and usually a good idea.