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

MODEL 211, 219 with Adaptive Brake (ABR) 

Fig 1: Locating Check Valve

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

	Remove/install
1	Operate the brake pedal several times when the engine is switched off	In order to reduce the vacuum in the brake booster (1).
2	Remove left cover (2) in engine compartment
3	Connect vacuum tester (01) to brake booster (1)		AR43.10-P-0024-01V
4	Start the engine and produce a vacuum of 0.75 to 0.8 bar by pressing and suddenly releasing the accelerator pedal	If the vacuum is above 0.8 bar, reduce it by depressing the brake pedal.
5	Turn off engine
	Checking
6	Check check valve (3) and brake booster (1) for pressure loss	The vacuum must not drop by more than 0.2 bar within 30 seconds. With vacuum loss >0.2 bar: Replace the vacuum line (4) with check valve (3):
		Model 211 with engine 273 Model 211 except engine 273 Model 219 with engine 156, 272, 273, 642 Then repeat the pressure loss test; if necessary: ↓	AR43.10-P-0355T
		Check brake booster (1).	AR43.10-P-0325T
7	Install in the reverse order