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Old 11-29-2012, 02:22 PM
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floydarogers floydarogers is offline
Pedant and Curmudgeon
Location: Renton, WA
Join Date: Oct 2010
Posts: 5,398
Mein Auto: 335d, 328d, Toyota T100
Originally Posted by SD Z4MR View Post
Also, brakes are not "powered off the engine". Brakes are a mechanical device with hydraulic assist. The hydraulic pump used in the brake system is powered by the engine.
This is not correct. Although a few braking systems (old BMW 7-series) use a hydraulic pump, virtually every one uses vacuum from the engine manifold to drive the brake assist diaphram. There is a small reservoir that runs out after a stop or two (whereupon the brakes still work, but you have to "stand on them".)

Even my 335d uses vacuum from an electric pump (as diesels don't have a throttle to create vacuum.)
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