Checking braking system for leaks using pressure gauge - AR42.10-P-0015GX

MODEL 463.270/ 271 

Fig 1: Identifying Braking Pedal Winch And Pressure Tester

Courtesy of MERCEDES-BENZ USA

	Check
	Risk of accident  caused by vehicle starting off by itself when engine is running. Risk of injury  caused by contusions and burns when working in engine during starting procedure	Secure vehicle to prevent it from moving. Wear closed and snug-fitting work clothes. Do not grasp hot or rotating parts.	AS00.00-Z-0005-01A
	Risk of poisoning  caused by swallowing brake fluid. Risk of injury  caused by brake fluid coming into contact with skin and eyes.	Pour brake fluid only into suitable and appropriately marked containers. Wear protective clothing and eye protection when handling brake fluid.	AS42.50-Z-0001-01A
	Brake fluid notes	All models	AH42.50-P-0001-01A
	Notes on repairs to brake system	All models	AH42.00-P-0003-01A
	Notes on externally invisible brake fluid loss	Models 129, 140, 163, 168, 170, 202, 203, 208, 209, 210, 215, 220, 452.3/4, 414, 460, 461.217/219/223/227/229/238/239/ 249/266/267/302/321/322/323/ 326/327/328/329/332/335/336/ 337/338/341/342/345/365/366/ 367/368/401/402/403/404/405/ 450/451/452/454/455/456/458/ 459, 463.200/204/206/207/208/209/ 220/221/224/225/227/228/230/ 231/232/233/240/241/244/245/ 247/248/249/250/254/270/271/ 300/304/307/308/309/320/321/ 322/323/324/325/327/328/330/ 331/332/333, 639	AH42.10-P-9406-02A
1	Take off left front wheel
	Remove/install wheels, rotate if necessary		AP40.10-P-4050G
2	Unscrew bleed screw at front left brake caliper and connect pressure tester (051).	Pressure testers (051) for hydraulic oil systems must not be used for systems with brake fluid otherwise the brake fluid is mixed with mineral oil which can lead to failure of the brake.
		Pressure tester (single and dual-circuit hydraulic brake systems)	*WH58.30-Z-1012-15A
3	Bleed pressure tester (051).
	High pressure test
4	Allow engine to run for 10 s at medium speed
5	With the engine running, depress brake pedal as far as possible using the brake pedal jack (080).	The pressure loss during the test duration of 5 minutes must not exceed 5 % of the regulated value. If the value is greater, this may result in failure of the brake system.
		Brake pedal winch	Fig 2
	Low-pressure check
6	Switch off engine and depress brake pedal until the vacuum is reduced.
7	Turn back brake pedal winch (080) until a line pressure of approx. 3 bar overpressure is still indicated on the pressure gauge	The line pressure must not fall during the test duration of 2 minutes. Loss of pressure may result in failure of the brake system.
		Brake pedal winch	Fig 2
8	Bleed brake system	After checking, only bleed the brake caliper or wheel brake cylinder to which the pressure tester (051) was connected.	AR42.10-P-0010GX

Fig 2: Identifying Brake Pedal Winch (000 589 18 31 00)

Courtesy of MERCEDES-BENZ USA

COMMERCIALLY AVAILABLE TOOLS

Number	Designation
WH58.30-Z-1012-15A	Pressure tester (hydraulic single / dual circuit brake systems)