Checking brake booster - AR43.10-P-0325NKB

MODEL 117, 156, 176, 242, 246 

Shown on MODEL 246 

Fig 1: Checking Brake Booster - Shown On Model 246

Courtesy of MERCEDES-BENZ USA

	Risk of injury  due to fan starting unexpectedly	Do not reach into the rotation or hazard area of the fan. Wear closed and close-fitting work clothes.	AS20.40-Z-0001-01A
	Risk of poisoning  from swallowing brake fluid. Risk of injury  from skin and eye contact with brake fluid	Only pour brake fluid into suitable and appropriately marked containers. Wear protective clothing and eye protection when handling brake fluid.	AS42.50-Z-0001-01A
	Brake fluid notes		AH42.50-P-0001-01A
	Check
1	Depress brake pedal several times with engine switched off to reduce the vacuum in the BAS brake booster (A7/7)
2.1	Remove cylinder head cover trim	Model 117, 156, 176, 246 with engine 607 Model 117, 156, 176, 246 with engine 651
		Model 117, 156, 176, 246 with engine 651 Model 117, 176, 246 with engine 607	AR01.20-P-5014-02OLB
2.2	Remove engine cover	Model 117, 156, 176 with engine 133 Model 117, 156, 176, 242, 246 with engine 270
3	Remove charge air pipe	Model 117, 156, 176, 246 with engine 651	AR09.41-P-8620OLB
4	Connect vacuum tester (030) with test connection (031) to BAS brake booster (A7/7)		AR43.10-P-0024-01V
		Brake booster Ø	*BE43.10-P-1001-01D
		Boost factor	*BE43.10-P-1002-01D
		Vacuum tester	Figure
		Test connection	Figure
5	Connect pressure tester (051) to brake caliper using connection fitting
	000 588 07 21 00 Test equipment		WS42.00-P-0014B
		Use correct connection fitting (pitch, cone etc.). Otherwise leaks and measurement errors can occur.
		Bleed screw on brake caliper	*BA42.10-P-1001-10N
		Bleed screw to brake caliper	*BA42.10-P-1002-12J
6	Connect pedal force measuring instrument (060) at brake pedal
	000 588 05 21 00 Roller brake test stand		WS42.00-P-0006B
7	Start engine and by opening the throttle produce a vacuum of 0.75 to 0.80 bar	If this vacuum is not reached or it drops immediately, the seal between the BAS brake booster (A7/7) and master brake cylinder may be damaged or the check valve (17) in the vacuum line (8) may be defective. In this case: ↓
		Check the check valve (17)	AR43.10-P-0023NKB
8	Replace seal between BAS brake booster (A7/7) and master brake cylinder	If a vacuum of 0.75 to 0.80 bar is not reached or drops immediately and the check valve (17) is not defective.
			AR42.10-P-0300NKB
9	Apply the specified force to the brake pedal and read off the line pressure on the pressure tester (051)	In order to cover measurement errors (incorrect force on the brake pedal, incorrect vacuum) and scatter of the measuring devices, a tolerance of 10 bar on the specified value is permissible. The measured value must be within the value range.
		Brake line pressure	*BE43.10-P-1003-01D
10	Detach vacuum tester (030) with test connection (031) from BAS brake booster (A77)
11	Detach pressure tester (051) with connection fitting from brake caliper
12	Install charge air pipe	Model 117, 156, 176, 246 with engine 651	AR09.41-P-8620OLB
13.1	Install trim panel of cylinder head cover	Model 117, 156, 176, 246 with engine 607 Model 117, 156, 176, 246 with engine 651
		Model 117, 156, 176, 246 with engine 651 Model 117, 176, 246 with engine 607	AR01.20-P-5014-02OLB
13.2	Reinstall engine cover	Model 117, 156, 176 with engine 133 Model 117, 156, 176, 242, 246 with engine 270
14	Remove pedal force meter (060) from brake pedal
15	Bleed brake system		AR42.10-P-0010NKB
		Only bleed the brake caliper to which the pressure tester (051) was connected.
	Risk of accident  from vehicle starting off by itself when engine running. Risk of injury  (bruises and burns) resulting from working on the engine while it is being started or when it is running.	Secure vehicle to prevent it from starting off by itself. Wear closed and snug-fitting work clothes. Do not touch hot or rotating parts.	AS00.00-Z-0005-01A
16	Check brake system for leaks		AR42.10-P-0100-01V

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

Courtesy of MERCEDES-BENZ USA

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

Courtesy of MERCEDES-BENZ USA