* Proportioning Valve: This is the most likely candidate if you're referring to something regulating brake pressure. The proportioning valve reduces brake pressure to the rear wheels to prevent rear-wheel lockup during braking, especially on a vehicle's rear drum brakes. It's a crucial part of the braking system, but not a "block" in the literal sense. It's usually located near the rear axle, but its exact location varies slightly by year and trim.
* T-fitting or Junction: The rear brake lines may have a T-fitting or similar junction where the lines split to go to each individual rear wheel. This isn't a "block" but a connector.
* Restriction (rare and unlikely): There might be a very rarely used internal restriction in some components, but it wouldn't be a standalone, externally identifiable block.
* Obstruction (problem): If you're experiencing brake problems, the "block" might refer to a clog, corrosion, or other obstruction *inside* a section of the brake line. This is a serious problem requiring immediate attention.
To find out what you're looking for, you'll need to be more specific about *why* you're asking about a block. If you're experiencing a brake issue, consult a qualified mechanic immediately. Don't attempt brake repairs yourself unless you have extensive automotive experience.
