S 500 Sedan (140.051) V8-5.0L (119.980) (1996)
Vacuum Brake Booster: Testing and Inspection
Check Brake Booster
Inspect
1
Operate brake pedal several times until vacuum in brake booster is reduced
2
Disconnect tester from brake booster
3
Connect, disconnect pressure tester (051) to connection at brake caliper
NOTE: After testing, only bleed the brake caliper to which the pressure tester was connected.
4
Fit, remove pedal force measuring instrument (060) at brake pedal
5
Start the engine and create a vacuum of 0.75 - 0.80 bar by pressing and then suddenly releasing the accelerator pedal.
NOTE: If a considerably lower vacuum is achieved or if the vacuum decreases immediately, the O-ring between the brake booster and tandem
master brake cylinder may be damaged, or the check valve in the vacuum line may be defective, Check non-return valve
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Vehicle with diesel engine - check vacuum pump:
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Model 202 with Engine 601
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Model 202 with Series 604, 605 engine
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Model 140 with Engine 603
6
Supply brake pedal with specified force and read line pressure (see line pressure under Adjustments)
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To cover measurement errors as far as possible (wrong force on brake pedal, wrong vacuum) and measurement scatter of the gauges, a
tolerance of ± 10 bar on the specified value is permissible.
7
Bleed brake system.