UAZ PATRIOT Operation Manual page 146

Proportioning valve. The motor vehicles without ABS are
equipped with the proportioning valve (Fig. 9.33), which ensures
the optimal distribution of braking forces between the axles of
motor vehicle and prevent the rear wheels from blocking earlier
than the front wheels. When servicing the motor vehicle check
the proportioning valve and clean it from dirt and check its
attachment. Make sure by visual inspection that the valve and its
drive details are not damaged, the brake fluid does not leak and
the coupling of the pillar with the flexible arm and the bracket
on the rear axle has no play.
When pressing the brake pedal, proportioning valve piston 17
should move out from the housing for 1.7-2.3 mm. If the piston
has no stroke, as well as poor or excessive stroke, the valve or
its drive have malfunctions.
When inspecting the hydraulic drive pay attention to protective
boot 1, to the position of gauge plug 15 and to brake fluid leaks
from it. The plug should normally be sunk into the housing
orifice of the valve up to the stop. If the plug comes out and
the brake fluid leaks, the valve must be replaced.
The protective boot should be tightly installed in the seat of
the piston and the housing should have no damages.
During the operation and during rear springs replacement,
adjust the force of flexible arm 4 (Fig. 9.34) to the valve piston.
For adjustment do the following:
1. Install the motor vehicle on even level ground.
2. Loosen the locknut of adjusting bolt 3 and unscrew the
bolt for 2-3 turns.
1 — proportioning valve; 2 — drive lever; 3 — adjusting bolt; 4 — flexible arm;
5 — arm pillar
Fig. 9.34. Proportioning valve drive:
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