Checking check valve - AR43.10-P-0023V

MODEL 171.442/ 456/ 473 

Fig 1: Checking Check Valve

Courtesy of MERCEDES-BENZ USA

	Check
1	Reduce vacuum in BAS brake booster (A7/7)	To do this, press the brake pedal several times with the engine switched off.
2	Open engine hood and raise to vertical position		AR88.40-P-1000V
3	Connect vacuum tester (030) with test connection (031) to BAS brake booster (A7/7)		AR43.10-P-0024-01V
		Vacuum tester	Fig 2
		Test connection	Fig 3
4	Start the engine and produce a vacuum of 0.75 to 0.8 bar by pressing and suddenly releasing the accelerator pedal	Reduce vacuum >0.8 bar by pressing brake pedal.
5	Turn off engine	The vacuum must not reduce by more than 0.2 bar within 30 seconds. In the event of a vacuum loss > 0.2 bar: Replace vacuum line (8) with check valve (17).
		Model 171.442	AR43.10-P-0355V
		Models 171.456/473 ↓ If necessary.	AR43.10-P-0355VA
		Checking brake booster	AR43.10-P-0325V
6	Detach vacuum tester (030) with test connection of BAS brake booster (A7/7)

Fig 2: Identifying Vacuum Tester (201 589 13 21 00)

Courtesy of MERCEDES-BENZ USA

Fig 3: Identifying Test Connector (168 589 08 63 00)

Courtesy of MERCEDES-BENZ USA