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516

BRAKE SYSTEM

VACUUM LEAK TEST

Run engine to medium speed. Release accelerator

and turn Engine OFF. This builds up the vacuum.

Wait for 90 seconds and then apply brakes. Two or

more applications should be vacuum assisted.

IF APPLICATIONS ARE NOT VACUUM

ASSISTED disconnect vacuum hose from

vacuumsource or NRVwhichever is easier.

If disconnected from NRV, attach short

length of hose to valve.

IF APPLICATIONS ARE

VACUUM ASSISTED there is

no vacuum leak.

Perform the HYDRAULIC LEAK

TEST.

Blow into hose attached to NRV. If air

passes through, valve is defective.

IF NRV or CHECK VALVE IS

DEFECTIVE install new NRV

and repeat VACUUM LEAK

TEST.

IF NRV OR CHECK VALVE IS

OK, vacuum booster is leaking

and should be replaced

.

HYDRAULIC LEAK TEST

Depress and release brake pedal several

times. Then hold pedal depressed with

medium pressure

.

IF PEDAL FALLS AWAY hydraulic system is

leaking. Check for external leakage at wheel

cylinders, brake pipes, hoses or joints.

If there is no external leak, there may be an

internal leak (master cylinder seals). Repair

or replace parts needed to correct leak.

IF PEDAL DOES NOT

FALLS AWAY hydraulic

system is not leaking.