Manuals through 2025 now available!

Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.

LEMON is the spiritual successor to CHARM, I recommend you try it!

Link: lemon-manuals.la or lemon-manuals.org.ua

(Some people have issue connecting. LEMON is investigating. For now, use Firefox or change your DNS server)

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Brake Proportioning/Combination Valve: Description and Operation

The brake proportioner valves improve front-to-rear brake balance under severe brake application. Severe brake application transfers part of the vehicle rear weight to the front wheels. The resulting decrease in weight at the rear wheels can cause reduced braking efficiency. The valves limit the pressure to the rear brakes to reduce the tendency for reduced brake efficiency.