Remove/Install Master Brake Cylinder - AR42.10-P-0300FR

Model 257 

Model 290 

Shown on model 257 

Fig 1: Master Brake Cylinder Components Location - Model 257

Courtesy of MERCEDES-BENZ USA

	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
Notice	Notes on externally invisible Brake fluid loss		AH42.10-P-9406-02A
Notice	Notes on repairs to Brake system		AH42.00-P-0003-01A
Notice	Brake fluid notes		AH42.50-P-0001-01A
	Notes on safety-relevant components		AH00.00-Z-0019-01A
	Remove/install
1	Remove vacuum in BAS Brake booster (A7/7) by depressing Brake pedal several times.
2	Remove Brake fluid reservoir.		AR42.10-P-0301FR
3	Clean master Brake cylinder (1) in the area of the connections of the Brake lines (2).	Thoroughly clean area around connecting points before opening Brake system. Otherwise minute dirt particles in the hydraulic component parts can result in malfunctions and total failure of the Brake system. Use clean, lint-free rag only. Do not use any compressed air for cleaning when the Brake system is open.
		Assembly cleaner	*BR00.45-Z-1028-04A
4	Remove Brake lines (2) from master Brake cylinder (1). Note on calculation of tightening torque when using insertion or socket tools with various effective lengths		AH00.00-P-0015-01CW
		Retaining screw, Brake line to master Brake cylinder	*BA42.10-P-1003-04P
		Box wrench bit	Fig 2
5	Seal connection fittings on master Brake cylinder (1) and Brake lines (2).	Record plug	Fig 3
6	Unscrew nut (3) and nut (arrow)
Notice	Notes on self-locking nuts and bolts		AH00.00-P-0001-01KOA
		Replace nut (3) and nut (arrow).
		Nut, Brake master cylinder to Brake booster	*BA42.10-P-1001-05L
7	Guide master Brake cylinder (1) out under the strut (4) out of BAS Brake booster (A7/7) and subsequently remove towards rear.	Collect Brake fluid which runs out with an absorbent rag. Otherwise, the paint will be damaged. Do not tilt the master Brake cylinder (1); pull it forward and in a straight line out of the BAS Brake booster (A7/7). The push rod will otherwise be pressed out of its axial position. Replace seal between master Brake cylinder (1) and BAS Brake booster (A7/7).
8	Install in the reverse order.
9	Bleed Brake system.		AR42.10-P-0010FR
	Check
10	Perform Brake test on test stand.
			AP42.00-P-4290BA

MASTER BRAKE CYLINDER

Number	Designation		Model 257	Model 290
BA42.10-P-1001-05L	Nut, Brake master cylinder to Brake booster	Nm	25	25

BRAKE LINES, BRAKE HOSES

Number	Designation		Model 257	Model 290.658/659/661 except code B07/U69
BA42.10-P-1003-04P	Retaining screw, Brake line to master Brake cylinder	Nm	16	16

BRAKE LINES, BRAKE HOSES

Number	Designation		Model 290.658/659/661 with code B07/U69, model 290.679/688/689
BA42.10-P-1003-04P	Retaining screw, Brake line to master Brake cylinder	Nm	16

Fig 2: Identifying Box Wrench Bit (140 589 00 03 00)

Courtesy of MERCEDES-BENZ USA

Fig 3: Identifying Record Plug (129 589 00 91 00)

Courtesy of MERCEDES-BENZ USA

REPAIR MATERIALS

Number	Designation	Order number
BR00.45-Z-1028-04A	Assembly cleaner	A 000 986 56 01