An In-Depth Look At Inboard Brakes

10 August 2015
 Categories: , Blog


The automotive world has seen some pretty unusual brake setups, but the most unusual is the inboard rear disc brake. Unlike conventional disc brakes that are mounted behind the rear wheels, these brakes are located alongside the vehicle's rear differential. Inboard brakes were commonly found on British and European vehicles throughout the 1960s and 1970s.

The Reason for Inboard Brakes

Few unconventional systems are used without a tangible benefit, and inboard brakes are no exception to this rule. Moving the braking hardware further inward along the axle helps lower the vehicle's unsprung weight (weight that's not supported by the vehicle's suspension). Keeping a car's unsprung weight low improves overall suspension performance, allowing for better cornering and overall handling capability.

Inboard brakes are commonly mounted directly onto the differential casing or another rigid mounting point on the axle. This also helps lower unsprung weight, since the weight of the braking hardware is no longer carried directly by the wheels.

Changing Inboard Brakes

Unfortunately, inboard brakes offer a few challenges when it comes to serviceability. To access the braking hardware, you'll have to raise the rear of the vehicle with floor jacks and support the weight of the vehicle with jack stands. In most cases, this will give you access to the brake calipers and the pads therein. Beyond that, the process for changing the brake pads is relatively similar to outboard-mounted brakes.

Changing the brake rotor usually requires the drive axles be disconnected from the differential, adding an extra step that's usually avoided on vehicles with outboard-mounted brakes. For this reason, changing the rear brake rotors can be a time-consuming experience in comparison to changing the brake pads.

On some vehicles, the entire rear axle subframe can be dropped for better access to the inboard brakes. This step may even be mandatory for vehicles that would otherwise offer relatively poor access to the braking hardware.

Other Considerations

Air flow can also be an issue for inboard brakes, since there's not as much air flowing underneath the vehicle compared to the rear wheels. The unique placement of the rear brakes also puts them in close proximity to the vehicle's exhaust pipes. This not only causes heat dissipation issues, but the added heat can also harden various seals within the brake calipers and axle shafts over time.

For this reason, vented discs are a popular upgrade for vehicles that originally came with solid discs. Vented brakes not only cool down faster after hard braking, but the vents also increase air flow throughout the immediate area.

For more information about brakes, contact Elkhart Auto Center or a similar location.